GEOGRAPHY-ENGLISH-SEM-VI-PAPER-8-munotes

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INTRODUCTION TO BIOGEOGRAPHY
Unit structure:
1.0 Objectives
1.1 Introduction
1.2 Biogeography -Concept, definition, nature, and Scope
1.3 Historical Development and Branches of Biogeography
1.4 Approaches in Biogeography
1.5 Importance of Biogeographic Studies
1.6 Summery
1.7 Exercise
1.0 OBJECTIVE
1. understand the Concept, definition, nature, and Scope of biogeography
2. know the Historical Development and Branches of Biogeography
3. Learn about Approaches in Biogeography
4. understand the Importance of Biogeo graphic Studies
1.1 INTRODUCTION
Geography is the scientific study of the earth’s surface. As we know there
is no informality in the earth’s surface in world. Because the climate factor
is a prominent factor that makes difference from region to region.
Geography is divided into two main branches physical geography and
human geography. Physical geography deal with natural phonemical
factors. physical geography is divided into other branches that are -
Geomorphology, climatology, Environment Geography, Ocean ography
and Biogeography. We are going to know about biogeography.
Biogeography means the study of living things and non -living things in a
particular area. The focus of biogeography is how a species origin,
develops and disperses to our area. We will lea rn in this unit about
branches of biogeography. An important study of biogeography etc.


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2 1.3 BIOGEOGRAPHY - CONCEPT, DEFINITION,
NATURE, AND SCOPE
Biogeography is a branch of geography that studies the past and present
distribution of the world's many a nimal and plant species and is usually
considered to be a part of physical geography as it often relates to the
examination of the physical environment and how it affected species and
shaped their distribution across the world. Alfred Russel Wallace studie d
the distribution of flora and fauna in the Amazon Basin and the Malay
Archipelago in the mid -19th century. His research was essential to the
further development of biogeography, and he is considered the "father of
Biogeography".
Biogeography is the stud y of the geographic distribution of plants,
animals, and other forms of life. It is concerned not only with habitation
patterns but also with the factors responsible for variations in
distribution.Strictly speaking, biogeography is a branch of biology, but
physical geographers have made important contributions, particularly in
the study of flora. Modern advancements in the classification of vegetation
and the preparation of maps of vegetation began in the 20th century with
the work of American botanists For rest Shreve, Homer L. Shantz, Hugh
M. Raup, and others.Biogeographic studies divide Earth’s surface —
primarily the continents and islands —into regions exhibiting differences
in the average composition of flora and fauna. It is thought that the
present -day d istribution patterns of plant and animal forms, as reflected in
such biogeographic regions, are the result of many historical and current
causes. These causes include present climatic and geographic conditions,
the geologic history of the landmasses and th eir climates, and the
evolution of the taxon (e.g., genus or species) involved. Investigators have
found that rate of dispersal, adaptability to prevailing environmental
conditions, and the age of the taxa being studied also have a significant
impact on th e pattern and extent of distribution.
What is biogeography?
“Biogeography, the study of the geographic distribution of plants, animals,
and other forms of life. It is concerned not only with habitation patterns
but also with the factors responsible for va riations in the distribution”
Buffon proposed a mechanism to explain biogeographic patterns: that
species 'improve' or 'degenerate' according to their environment. Given
generality and often incorporating multiple facets, a theory may emerge
that explains the patterns well (e.g. evolutionary theory)
- by Buffon
Alfred Russel Wallace studied the distribution of flora and fauna in the
Amazon Basin and the Malay Archipelago in the mid -19th century. His
research was essential to the further development of bioge ography, and he
was later nicknamed the "father of Biogeography".
by - Alfred Russel Wallace munotes.in

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Introduction t o Biogeography
3 “Biogeography as the branch of physical geography;geography of organic
life, the study of spatial distribution of animate nature, includingboth
plants and animals and the processes that produce variations in the
patterns ofdistribution”.
By - According to Browne,
“Biogeography, as the term indicates, is both a biologicaland a
geographical sci ence. Its field of study is the biologically inhabited part of
thelithosphere, atmosphere and hydrosphere - or, as it has become known -
the biosphere”.
By According to J. Tivy,
Biogeography refers to the distribution of various species and ecosystems
geograp hically and throughout geological time and space. Biogeography is
often studied in the context of ecological and historical factors which have
shaped the geographical distribution of organisms over time. Specifically,
species vary geographically based on l atitude, habitat, segregation (e.g.,
islands), and elevation. The subdisciplines of biogeography include
zoogeography and phytogeography, which involve the distribution of
animals and plants, respectively.
SCOPE AND NATURE OF BIOGEOGRAPHY
Biogeography is c losely related to ecology which is the study of the inter -
relationships between organisms and their habitat. The organism home or
habitat could vary from a small micro habitat such as under a stone or a
leaf to Biomes which could be a tropical rainforest o r desert. However,
biogeography is a broad discipline but has two main branches
Ecological Biogeography which is the present distributions and
geographic variation in diversity, how biotic and abiotic interactions
influence species distributions, interacti ons between species (e.g.,
predation and competition).
Historical Biogeography which is the second deals with continental drift,
glaciation, evolutionary lineages reconstructing the origin, dispersal and
speciation and extinction of species.
However, the t erm biogeography is the study of the geographic patterns of
species distribution; it is an aspect of physical geography that examines
the physical environment and the way it affects the distributions of various
species on the earth surface. The discipline is related to biology, ecology,
evolution studies, climatology, and soil sciences as they are relate to
animal populations and the factors that allow them to flourish in particular
regions of the globe. In that case, we are unable to separate biogeography
from its related fields, since biogeography is relying heavily on theory and
data from other related subjects.
In the late nineteenth and early twentieth centuries, biogeography was a
focus of analysis across disciplines such as geography, anthropology and
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Biogeography
4 societies and for those concerned with the distribution and viability of
animal or plant populations.
Biogeography seeks to describe and analyze distributional patterns
exhibited by organ isms at present and in the past. To enable it to
comprehend distributional patterns, biogeography needs to study physical
and organic factors as they are now and how they were in time past. To
acquire this knowledge, it must use information drawn largely f rom the
natural and earth sciences. It is an interdisciplinary subject within these
domains.
1.4 HISTORICAL DEVELOPMENT AND BRANCHES
OF BIOGEOGRAPHY
To better understand the current field of biogeography, it is important to
explore the foundations and hist ory of the science. Biogeography is a
synthetic study, which is based in part on the subjects of community
ecology, geology, systematics, evolutionary biology, and palaeontology.
The development of the subject of biogeography may be broken into four
histor ical periods.
1600 –1850: The Age of Reason
Early studies of organisms’ geographic distributions were focused on
descriptive studies with historical explorations. These scientists focused
on documenting spatial patterns of organisms, emphasizing on the effe cts
of climate, latitude, and altitude. Comte de Buffon (1707 –1788), also
known as Georges -Louis Leclerc, determined that distant regions with
similar climate and similar -appearing vegetation have different animal
species. This is now referred to as Buffon 's Law. He is also the author of
Histoire Naturelle, a 44 -volume natural history encyclopedia. Carl
Linnaeus (1707 –1778) studied the plants and animals spread from Mount
Ararat in Turkey to explore the idea of the biblical flood. As a result of
documenting elevational zones of Ararat, he came up with the idea of
biomes defined as major ecological communities. In addition, Carl
Linnaeus is considered the father of the science of taxonomy, which is the
science of classification.This time period is also known as a great age for
exploration. Johann Reinhold Forster (1729 –1798) was the naturalist on
James Cook's second Pacific voyage in 1778. He advanced biogeography
by creating global biotic regions for plants. Forster noted the higher -
species diversity in the t ropics, as well as species diversity being
correlated with island size. Alexander von Humboldt (1769 –1859) created
a botanical geography that was foundational to the field of biogeography.
He determined that plant vegetation types are strongly correlated w ith
local climate to create latitudinal belts of vegetation. Moreover, he
developed elevational vegetation zones for the Andes in South America.


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Introduction t o Biogeography
5 1850 –1900: Evolution by Natural Selection
The idea of evolution based on natural selection greatly altered t he way
species distributions were explained. Charles Darwin (1809 –1882) is most
famous for publishing The Origin of Species, outlining his idea of
evolution through natural selection. Natural selection occurs when
individuals in a population either do not survive equally well or do not
breed equally well, or both due to inherited differences. Evolution in turn
can be thought of in two ways: (1) microevolution and (2) macroevolution.
In microevolution, evolution is considered as changes in the genetic
compos ition of a population with the passage of each generation. For
macroevolution, evolution is the gradual change of organisms from one
form into another, with the origins of species and lineages from ancestral
forms. For an example, Darwin studied the variat ions in mockingbirds on
different Galapagos Islands. This divergent evolution is a diversification
over evolutionary time of a species into several different species,
commonly referred to as adaptive radiation.
Alfred Russel Wallace (1823 –1913) is also fam ous for independently
developing the idea of evolution by natural selection, based on his work in
Indonesia. He found that the species on Sumatra and Java were very
different from nearby New Guinea, even though the climates were similar.
Wallace's study of biota in Southeast Asia showed geographic distance is
not equal to taxonomic similarity, and the boundary area between these
islands is now referred to as Wallace's Line. Wallace is also considered to
be the originator of zoogeography, which is the biogeo graphy focused on
animals. Wallace integrated geological, fossil, and evolutionary
information to consider paleoclimate influences distributions, developing
six great biotic regions.
Other notable contributions to biogeography during this period include
mapping biotic regions and understanding limiting factors. Philip
LutleySclater (1829 –1913) advanced the subject of biogeography with his
defining terrestrial biotic regions for birds and marine regions for marine
mammals. Justus Liebig (1803 –1876) changed t he way scientists viewed
restrictions on organisms away from a focus on total resources available
with his law of the minimum. The law of the minimum states that the
scarcest resource (or limiting factor) in the environment makes it difficult
for a species to live, grow, and reproduce.
1900 –1950: Continental Drift and Ecology
Themes in biogeography in the first half of the 20th century focused on
links to paleontology, centers of species origins, and the biological species
concept. The emphasis in the scien ce of biogeography was on evolution,
history, dispersal, and mechanisms of survival. The greatest impact on
biogeography in this period was the theory of continental drift in 1912 and
1915 by the German geologist Alfred Wegener (1880 –1930). Before the
theory of plate tectonics, it was difficult for biogeographers to explain
certain patterns of species distributions with the assumption that land
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Biogeography
6 actually not widely accepted until the 1960 s when proof of continental
drift came from a series of linear magnetic anomalies on either side of the
Mid-Atlantic Ridge. With the acceptance of the continental drift theory,
biogeographers could now explain the disjunct biogeographic distribution
of pre sent-day organisms found on different continents but having similar
ancestors.
Species can interact as continents collide. Subsequently, when the
continents separate, they take their new species with them.
Biogeographers now ponder how plate tectonics may have affected the
evolution of life. In turn, biogeographers offer evidence for plate tectonics
such as dispersal of species via such corridors as the Bering land bridge or
widely separated (“disjunct”) species distributions that can't be explained
by dis persal; for instance, Nothofagus (southern beech) trees, which only
occur in Southern South America and in New Zealand.
In addition to historical explanations of organism distributions,
biogeographers also examined ecological reasons for spatial patterns.
Theories on ecological succession were formally developed in the late
1800s and early 1900s to show predictable and orderly changes in the
composition or structure of ecological communities. In 1899, Henry
Cowles published his study of stages of vegetation development on dunes
along Lake Michigan. In 1916, Frederic Clements published his famous
theory of vegetation development focusing on gradual changes over time
to best fit the local conditions. His climax theory of vegetation -dominated
plant ecology was later largely replaced by other models, notably by
Henry Gleason's 1926 concept of distribution of plants depending on the
individual species rather than Clements's idea of plant associations. In
1934, Christen Raunkiaer (1860 –1938) helped change the way
biogeographers classified species with life forms based on ecological
rather than taxonomic classification. In 1935, Sir Arthur Tansley (1871 –
1955) refined the term ecosystem to mean the whole complex natural unit
in a system consisting of all plants, anima ls, and microorganisms (biotic
factors) in an area functioning together with all the nonliving physical
(abiotic) factors of the environment.
1950 –Present: Ecological and Historical Theories Since 1950, the field of
biogeography has been revitalized with a dvances in ecological and
historical theories focused on phylogenetic classification to related
different species, mechanisms limiting geographic distribution, and
distances and size influencing number of species in an area.
During this period, the concep t of new species arising due to geographic
isolation was developed by Ernst Mayr (1904 –2004). Mayr is also well -
known for defining the “biological species concept” as potentially
interbreeding to produce fertile offspring. In addition, Mayr helped define
the term cladistics to refer to classifications, which only take into account
geneology, based on evolutionary ancestry. Cladistics, or phylogenetic
classification, views a species as a group of lineage -connected individuals,
compared with the traditional L innaean taxonomy, which focused on the
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Introduction t o Biogeography
7 which different groups branched off from their common ancestors,
arranged with the most closely related species on adjacent branches of the
phylogenetic tree.
Theories also expanded during this time period on how a species can occur
in widely geographically separated areas and the mechanisms that limit
these distributions. In 1958, Leon Croizat (1932 –1982) published his
concept of “vicariance bi ogeography” to explain disjunction of multiple
species due to the growth of barriers instead of via dispersal. Croizat's
works include . Manual of Phytogeography (1952), Panbiogeography
(1958), and Space, Time, Form (1964). Robert Harding Whittaker (1920 –
1980) proposed a new method to analyze limits to plant distributions by
comparing species abundance with environmental gradients. His gradient
analyses approach focuses on abiotic factors such as light, water,
temperature, and soil nutrients in plant communi ties.
Biogeography during this period moved from observational to predictive
studies with the theory of island biogeography. In 1963, R. H. MacArthur
and E. O. Wilson hypothesized that species richness of an area could be
predicted to explain distributions . The theory states that if one knows the
rates of colonization and extinction of an island, then it is possible to
predict the number of equilibrium species that area could support. They
based the species richness prediction on two factors: (1) distance o f the
island from a mainland source of species for a colonization pool and (2)
the size of the island for available habitat and its variety of ecological
niches. With these two factors, MacArthur and Wilson predicted the
number of species the area could ma intain, as well as the turnover rate for
the area. According to island biogeography theory, small and distant
islands have a lower number of species that can be maintained compared
with large and near islands. The theory also states that there would be a
turnover of the species as new species colonize and old species go extinct,
but the number of species overall should achieve an equilibrium number.
This theory has been applied to other non -island areas that act like islands
due to habitat fragmentation, su ch as nature preserves and national parks.

BRANCHES OF BIOGEOGRAPHY:
The main branches of biogeography are
1. Historical Biogeography,
2. Ecological Biogeography, and
3. Conservation Biogeography.
There are three main branches in biogeography
1. Historical Bi ogeography:
This branch studies the evolutionary history of species and their
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Biogeography
8 It researches that past geological events, such as continental drift, have
influenced the distribution of species and their diversity.
2. Ecological Biogeography:
This branch studies the current distribution patterns of species and their
relationships with their physical and biotic environments.
3. Conservation Biogeography:
This branch is about the principles of biogeography to conserva tion
biology, focusing on the protection and management of endangered
species and ecosystems.
1.5 APPROACHES TO BIOGEOGRAPHY
Historical Biogeography – Reconstruct the origins, dispersal, and
extinctions of taxa and biotas
Ecological Biogeography – Account s for the present distributions in
terms of interactions between organisms and their physical and biotic
environments Paleoecology – Bridges the gap between these two fields,
investigating the relationships between communities (abundance,
distribution, an d diversity of species) and abiotic conditions (climate,
soils, water quality, etc.).Analytical Biogeographers - Develop general
mathematical rules of how geography affects the evolution and
distribution of plants and animals
Conservation Biogeography - Work on the protection and restoration of
natural environments
1.6 IMPORTANCE OF BIOGEOGRAPHIC STUDIES
1. Through observing the geographic distribution of species, we can see
associated variations in sea level, river routes, habitat, and river
capture. Addition ally, this science considers the geographic constraints
of landmass areas and isolation, as well as the available ecosystem
energy supplies.

2. Biogeography is one of the Life sciences which deal with the study of
distribution of species and ecosystems in ge ographic area and through
geological time. Organisms and biological groups regularly differ in a
common fashion along geographic gradients of latitude, elevation,
isolation and habitat region. Phytogeography is the department of
biogeography that studies t he distribution of plants.

3. Zoogeography is the department that studies the distribution of
animals. Mycogeography is the department that studies the fungi
distribution like mushrooms. Biogeography is an integrative subject of
inquiry that unites ideas an d facts from ecology, evolutionary biology,
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Introduction t o Biogeography
9 climatology. Modern biogeographic studies combine ideas and
information from many fields, from the physiological and ecological
constraints on organismal d ispersal to geological and climatological
phenomena running at worldwide spatial scales and evolutionary time
frames. The short -period interactions within a habitat and species of
organisms describe the ecological application of biogeography.

4. Historical biogeography describes the longtime period, evolutionary
durations of time for broader classifications of organisms. Early
scientists, starting with Carl Linnaeus, contributed to the development
of biogeography as a life science. The scientific principle o f
biogeography grown out of the work of Alexander von Humboldt
(1769 –1859), Francisco Jose de Caldas (1768 - 1816), Hewett Cottrell
Watson (1804 –1881), Alphonse de Candolle (1806 –1893), Alfred
Russel Wallace (1823 –1913), Philip LutleySclater (1829 –1913) and
other biologists and explorers. The patterns of species distribution
throughout geographical regions can generally be defined through a
mixture of historical elements like: speciation, extinction, continental
drift, and glaciation. Through observing the g eographic distribution of
species, we can see related versions in sea level, river routes, habitat,
and river capture. Additionally, this science considers the geographic
constraints of landmass regions and isolation, as well as the available
ecosystems en ergy supplies.

5. Modern biogeography regularly employs the usage of Geographic
Information Systems (GIS), to recognize the elements affecting
organism distribution, and to predict future trends in organism
distribution. Often mathematical models and GIS ar e employed to
clear ecological troubles which have a spatial aspect to them.
Biogeography is most keenly observed on the world's islands. Islands
are best places due to the fact that they enable scientists to observe and
study the habitats which are new in vasive species that are currently
colonized and can be examined how they disperse through the island
and modify it. Islands are very diverse in their biomes, starting from
the tropical to arctic climates. This diversity in habitat enables for a
wide variet y of species study in various parts of the world.
Biogeography includes many different fields but not only limited to
physical geography, geology, botany and plant biology, zoology,
general biology, and modelling. Biogeography is being implemented
in biodi versity conservation and planning, projecting global
environmental modifications on species and biomes, projecting the
spread of infectious diseases, invasive species, and for supporting
planning for the establishment of crops. Technological evolving and
advances have allowed for producing an entire suit of predictor
variables for biogeographic analysis.



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Biogeography
10 1.7 SUMMERY
Biogeography is the study of the geographic distribution of plants,
animals, and other forms of life. It is concerned not only with habitat ion
patterns but also with the factors responsible for variations in
distribution.Strictly speaking, biogeography is a branch of biology, but
physical geographers have made important contributions, particularly in
the study of flora. Modern advancements in the classification of vegetation
and the preparation of maps of vegetation began in the 20th century with
the work of American botanists Forrest Shreve, Homer L. Shantz, Hugh
M. Raup, and others.Biogeographic studies divide Earth’s surface —
primarily the c ontinents and islands —into regions exhibiting differences
in the average composition of flora and fauna. It is thought that the
present -day distribution patterns of plant and animal forms, as reflected in
such biogeographic regions, are the result of many historical and current
causes. These causes include present climatic and geographic conditions,
the geologic history of the landmasses and their climates, and the
evolution of the taxon (e.g., genus or species) involved. Investigators have
found that rate of dispersal, adaptability to prevailing environmental
conditions, and the age of the taxa being studied also have a significant
impact on the pattern and extent of distribution.
1.8 EXERCISE
1. what is Biogeography? explain the nature and scope of Biogeogra phy.
2. discuss the development stages of B Biogeography.
3. explain all branches of Biogeography.
4. explain the importance of Biogeography.

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11 2
ECOSYSTEM AND BIOSPHERE
Unit structure:
2.0 Objectives
2.1 Introduction
2.2 Ecosystem: Concept, meaning and Types
2.3 Components of Ecosystem and Ecosystem productivity
2.4 Biosphere: Concept, meaning and components
2.5 Biogeographic processes
2.6 Summery
2.7 Exercise
2.0 OBJECTIVE
1. understand the Ecosystem: Concept, meaning and types
2. know the Components of ecosystem and ecosystem productivity
3. Learn about Biosphere: Concept, meaning and components
4. understand the Biogeographic processes
2.1 INTRODUCTION
Down the ages humans have learnt to exist in a variety of locations on the
earth. The interaction of humans with the environment (surroundings) in
these locations has often brought major changes in that environment.
Some changes were good, s ome were bad. Many times, the bad changes
were caused by humans making too much of a change in the environment,
by using or abusing the natural resources. Every location where people
have lived contained a community of plants, animals, insects, and other
natural resources. A community of organisms, other natural resources, and
their influence on each other is called an ecosystem. The plants and
animals existing in an ecosystem are those most adapted to that
environment.
A growing human population presents i ncreasing environmental
challenges around the world. The study of Environment and Ecosystem
helps in understanding the dynamics of ecology, environmental science,
and conservation management of natural resources, wildlife and
sustainable ecosystems and lan dscapes so that applicable solutions can be
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12 2.2 ECOSYSTEM : CONCEPT, MEANING AND TYPES
Ecosystems can be of different sizes consisting of a community of
organisms together with their physical environment. They can be marine,
aquatic, or terre strial. Broad categories of terrestrial ecosystems are called
biomes. In ecosystems both matter and energy are conserved. Energy
flows through the system usually from light to heat. But matter is recycled.
Ecosystems with higher biodiversity tend to be mor e stable with greater
resistance and resilience in the face of disturbances, disruptive events. In
an ecosystem each organism plays its own role.
2.2.1 Meaning of Ecosystem :
According to Woodbury, “Ecosystem is a complex in which habitat, plants
and anima ls are considered as one interesting unit, the materials and
energy of one passing in and out of the others”. An ecosystem includes all
the living things such as plants, animals and organisms in a given area,
interacting with each other, and also with thei r non -living environments
like weather, earth, sun, soil and climate. Ecosystems are the foundations
of the biosphere and they determine the health of the entire earth system.
Although a complete self -sufficient ecosystem is rarely found in nature but
all the ecosystems of the earth are very well connected to each another
such as river ecosystem is connected with the ecosystem of ocean.
The term ecosystem was coined by A.G. Tansley in 1935, who defined it
as “the system resulting from the integration of al l the living and non -
living factors of the environment”
According to R. L. Lindeman (1942), the term ecosystem applies to “any
system composed of physical -chemical -biological processes within a
space -time unit of magnitude.”
According to Monkhouse and Smal l, “ecosystem is an organic community
of plants and animals viewed within its physical environment or habitat”.
From the above definitions of ecosystem, the following basic properties
emerge:
 Ecosystem of any given spatial - temporal unit represents the sum of all
living organisms and physical environment.
 It is a well -defined area.
 It is an open system characterized by continuous input and output of
the energy.
 It is mainly powered by solar energy.
 It is a functional unit.
 There is a complex interaction bet ween the biotic and abiotic
components.
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Ecosystem and Biosphere
13 Components and Function of Ecosystem
Components of Ecosystem
An ecosystem is a functional and structural unit of Ecology. This implies
that each ecosystem has a defin ite structure and components where each
component part of the system has a definite role to play in the functioning
of the ecosystem. Ecosystems have two major components. The living or
biotic components like plants and animals; and the nonliving or abioti c
components like water, air, nutrients and solar energy. These two parts of
the ecosystem continuously interact with one another.
 From the structure point of view all ecosystems consist of the
following basic components:
1. Abiotic components
2. Biotic compone nts
1. Abiotic Components :
Abiotic component of ecosystem includes all the physical and chemical
factors that influence living organisms, like air, water, soil, rocks etc.
Thus, it is an assemblage of organic and inorganic substances present in an
ecosyst em. Basic inorganic elements and compounds are soil, water,
oxygen, calcium carbonates, phosphates and a variety of organic
compounds such as by -products of organic activities. The physical factors
and ingredients like moisture, wind currents and solar rad iation are also
included in abiotic components. The various climatic factors that affect the
ecosystem functioning are also a part of this. Without sunlight, water, air
and minerals, life cannot exist. Hence the non -living components are
essential for the living world.
2. Biotic Components:
The biotic components include all living organisms present in the
environmental system. These can be classified as either producers or
consumers, depending on how they get their food. From nutrition point of
view, the b iotic components can be grouped into two basic components:
a. Autotrophic components - The autotrophic components include all
green plants which with the help of the radiant energy of sun
manufacture food from inorganic substances.
b. Heterotrophic components -The heterotrophic components include non -
green plants and all animals which take food from autotrophs.
 Thus biotic components of an ecosystem can be classified as under:
I. Producers (Autotrophic components)
II. Consumers
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Biogeography
14 I. Producers (Autotrophic elements) :
Producers can make the organic nutrients they need, using simple
inorganic compounds in their environment: for instance, the green plants
on land and the small algae in aquatic ecosystems produce their food by
the process of photosynthesis. For this the radiant energy of sun is used in
photosynthetic process whereby carbon dioxide is assimilated and the light
energy is converted into chemical energy. Oxygen is evolved as by -
product in the photosynthesis and used in respira tion by all living things.
II. Consumers :
Those living members of ecosystem which consume the food synthesized
by producers are called consumers. Consumers directly or indirectly
depend on food provided by producers. All kinds of animals that are found
in an ecosystem are called consumers. Depending on their food habits
consumers can be further classified into four types such as:
a. Consumers of the first order or primary consumers
b. Consumers of the second order or secondary consumers
c. Consumers of the third or der or tertiary consumers and Parasites,
scavengers and saprobes.
d. Decomposers and transformers
a. Primary consumers :
These are purely herbivorous animals that are dependent for their food on
producers or green plants. In a food chain, herbivores are refe rred to as the
primary consumers. The herbivores serve as the chief food source for
carnivores. Insects, goat, cow, rabbit, deer, buffalo are some of the
common herbivores in the terrestrial ecosystem, and small crustaceans,
molluscs, etc. in the aquatic h abitat.
b. Secondary consumers :
These are carnivores and omnivores. Carnivores are flesh eating animals
and they feed on herbivores (primary consumers). Examples of carnivores
are lions, tigers. Whereas the omnivores are the animals that eat both
plants and herbivores, e.g. pigs, rats, cockroaches and humans.
c. Tertiary consumers :
These are the top carnivores which prey upon other carnivores, omnivores
and herbivores. Lions, tigers, hawk, vulture, etc. are considered as tertiary
or top consumers.
Besid es different classes of consumers, the parasites, scavengers and
saprobes are also included in the consumers. The parasitic plants and
animals utilize the living tissues of different plants and animals. The
scavengers and saprobes utilize dead remains of a nimals and plants as
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15 d. Decomposers and transformers :
Decomposers digest the complex organic molecules in dead organic
matter (detritus) into simpler inorganic compounds. They absorb the
soluble nutrients as their food. Some examples are bacte ria, fungi, and
mites. The decomposers and transformers play very important role in
maintaining the dynamic nature of ecosystems.
The most important part of each ecosystem is that it will have certain
representative organisms playing each of the above ment ioned roles.
Function of Ecosystem
Functions of Ecosystem
An ecosystem is a functional and life sustaining environmental system.
The technical term 'Ecosystem function' is generally used to define the
biological, geochemical and physical processes and com ponents that take
place or occur within an ecosystem. In other words it relate to the
structural components of an ecosystem (e.g. vegetation, water, soil,
atmosphere and biota) and how they interact with each other, within
ecosystems and across ecosystems. Sometimes, ecosystem functions are
called ecological processes. An ecosystem is a functional and life
sustaining environmental system.
 In an ecosystem there are three functional components.
1. Inorganic constituents
2. Organism
3. Energy input
These three compone nts interact with each other to form an environmental
system. The primary producers convert inorganic constituents into organic
components by photosynthesis using the energy from the solar radiations.
The herbivores make use of the energy from the producer s and they
themselves serve as a food for the carnivores. Animals of different types
accumulate organic matter in their body which is taken as food. They are
known as secondary producers. The dead organic matters of plants and
animals are decomposed by bac teria and fungi which break the complex
molecules and liberate inorganic components. These are known as
decomposers. During this process some amount of energy is released in
the form of heat. The ecosystem of different habitats is interrelated with
one ano ther.
Maintaining ecosystem function is important to maintaining the capacity
of the region to supply ecosystem services. Those areas with high
ecosystem function have the potential to contribute to a wide range of
ecosystem services. But those areas showi ng few ecosystem functions are
also important as they may provide important contributions to specific
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16 2.3 COMPONENTS OF ECOSYSTEM AND
ECOSYSTEM PRODUCTIVITY

Ecological Pyramid Defini tion
An ecological pyramid is a graphical representation of the relationship
between different organisms in an ecosystem. Each of the bars that make
up the pyramid represents a different trophic level, and their order, which
is based on who eats whom, repr esents the flow of energy. Energy moves
up the pyramid, starting with the primary producers, or autotrophs, such as
plants and algae at the very bottom, followed by the primary consumers,
which feed on these plants, then secondary consumers, which feed on the
primary consumers, and so on. The height of the bars should all be the
same, but the width of each bar is based on the quantity of the aspect being
measured.
Types of Ecological Pyramids
Pyramid of numbers :
This shows the number of organisms in each t rophic level without any
consideration for their size. This type of pyramid can be convenient, as
counting is often a simple task and can be done over the years to observe
the changes in a particular ecosystem. However, some types of organisms
are difficul t to count, especially when it comes to some juvenile forms.
Unit: number of organisms.
Pyramid of biomass :
This indicates the total mass of organisms at each trophic level. Usually,
this type of pyramid is largest at the bottom and gets smaller going up, but
exceptions do exist. The biomass of one trophic level is calculated by
multiplying the number of individuals in the trophic level by the average
mass of one individual in a particular area. This type of ecological
pyramid solves some problems of the p yramid of numbers, as it shows a
more accurate representation of the amount of energy contained in each
trophic level, but it has its own limitations. For example, the time of year
when the data are gathered is very important, since different species have
different breeding seasons. Also, since it’s usually impossible to measure
the mass of every single organism, only a sample is taken, possibly
leading to inaccuracies. Unit: g m -2 or Kg m -2.
Pyramid of productivity :
The pyramid of productivity looks at th e total amount of energy present at
each trophic level, as well as the loss of energy between trophic levels.
Since this type of representation takes into account the fact that the
majority of the energy present at one trophic level will not be available f or
the next one, it is more accurate than the other two pyramids. This idea is
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17 of the energy in a trophic level will go towards creating biomass. In other
words, only about 10% of the en ergy will go into making tissue, such as
stems, leaves, muscles, etc. in the next trophic level. The rest is used in
respiration, hunting, and other activities, or is lost to the surroundings as
heat. What’s interesting, however, is that toxins are passed up the pyramid
very efficiently, which means that as we go up the ecological pyramid, the
amount of harmful chemicals is more and more concentrated in the
organisms’ bodies. This is what we call biomagnification.
The pyramid of productivity is the most wid ely used type of ecological
pyramid, and, unlike the two other types, can never be largest at the apex
and smallest at the bottom. It’s an important type of ecological pyramid
because it examines the flow of energy in an ecosystem over time. Unit: J
m-2 yr-1, where Joule is the unit for energy, which can be interchanged by
other units of energy such as Kilojoule, Kilocalorie, and calorie.
While a productivity pyramid always takes an upright pyramid shape,
number pyramids are sometimes inverted, or don’t tak e the shape of an
actual pyramid at all. To demonstrate, let’s take an oak tree, which can
feed millions of oakworms. If we consider this ecosystem as our focus,
then the producers’ level (one tree) will end up much smaller than the
primary consumers’ leve l (millions of insects). This is less likely to occur
in biomass pyramids, but is not impossible. The pyramids below show the
different types of pyramids and the shapes they can have in different
ecosystems.
Ecological Pyramid Examples :
The diagram below is an example of a productivity pyramid, otherwise
called an energy pyramid. The sun has been included in this diagram, as
it’s the main source of all energy, as well the decomposers, like bacteria
and fungi, which can acquire nutrients and energy from all trophic levels
by breaking down dead or decaying organisms. As shown, the nutrients
then go back into the soil and are taken up by plants.
The loss of energy to the surroundings is also shown in this diagram, and
the total energy transfer has been calcula ted. We start off with the total
amount of energy that the primary producers contain, which is indicated
by 100%. As we go up one level, 90% of that energy is used in ways other
than to create flesh. What the primary consumers end up with is just 10%
of th e starting energy, and, 10% of that 10% is lost in the transfer to the
next level. That’s 1%, and so on. The predators at the apex, then, will only
receive 0.01% of the starting energy! This inefficiency in the system is the
reason why productivity pyramid s are always upright.
FUNCTION OF ECOSYSTEM: FOOD CHAIN & WEB, ENERGY
TRANSFER
Food Chains :
All living organisms (plants and animals) must eat some type of food for
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18 photosynthesis. Using the e nergy from the sun, water and carbon dioxide
from the atmosphere and nutrients, they chemically make their own food.
Since they make or produce their own food they are called producers.
Organisms which do not create their own food must eat either plants or
animals. They are called consumers. Some animals get their energy from
eating plants while other animals get energy indirectly from plants by
eating other animals that already ate the plants. Animals that eat only
plants are called herbivores. Animals tha t eat both plants and other
animals are called omnivores. Animals that eat only other animals are
called carnivores. Some animals eat only dead or decaying materials and
are called decomposers. In the marine food web, special producers are
found. They are tiny microscopic plants called phytoplankton. Since the
water is the home for these special tiny plants; it is also the home for tiny
microscopic animals called zooplankton. And of course, zooplankton eat
phytoplankton. Sometimes zooplankton and phytoplank ton are
collectively referred to as plankton. Food chains show the relationships
between producers, consumers, and decomposers, showing who eats
whom with arrows. The arrows show the movement of energy through the
food chain. For example, in the food chain shown below, the small fish
(silverside) gets its energy by eating the plankton and the large fish
(bluefish) gets its energy by eating the small fish. Finally, the bacteria eats
the fish after it dies, getting its energy from the large fish. The bacteria
also returns nutrients back to the environment for use by the
phytoplankton.
Thus the food chain becomes a complete circle. Animals may eat more
than one type of food. They may eat many different types of plants or
many different animals. This makes ever ything more complicated and the
food chain becomes a food web.
Food Webs :
A food web is made up of interconnected food chains. Most communities
include various populations of producer organisms which are eaten by any
number of consumer populations. The gr een crab, for example, is a
consumer as well as a decomposer. The crab will eat dead things or living
things if it can catch them. A secondary consumer may also eat any
number of primary consumers or producers. This non -linear set of
interactions which sho ws the complex flow of energy in nature is more
easily visualized in the following diagram. In a food web nutrients are
recycled in the end by decomposers. Animals like shrimp and crabs can
break the materials down to detritus. Then bacteria reduce the det ritus to
nutrients. Decomposers work at every level, setting free nutrients that
form an essential part of the total food web.
ENERGY LOSS IN THE FOOD CHAIN AND FOOD WEB
In a food chain, energy is lost in each step of the chain in two forms: first
by the organism producing heat and doing work, and second, by the food
that is not completely digested or absorbed. Therefore, the food web
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19 are recycled by the decomposition of organisms. A s food is passed along
the food chain, only about 10% of the energy is transferred to the next
level. For example, 10% of the energy phytoplankton received from the
sun can be used by zooplankton at the next level. From one level to the
next about 90% of t he energy used by the previous level is lost. This
means that there has to be a lot more organisms at the lower levels than at
the upper levels. The number of organisms at each level makes a pyramid
shape and is called a food pyramid. To better understand this energy loss,
it is helpful to look at a food pyramid.
Energy Transfer :
Energy is transferred between organisms in food webs from producers to
consumers. The energy is used by organisms to carry out complex tasks.
The vast majority of energy that exis ts in food webs originates from the
sun and is converted (transformed) into chemical energy by the process of
photosynthesis in plants.
TYPES OF ECOSYSTEM :
There are many types of ecosystems and it is not possible to classify all of
them. There are essent ially two kinds of ecosystems; Aquatic and
Terrestrial. Any other sub -ecosystem falls under one of these two
headings.
2.3.1 Forest Ecosystem
Large group of trees shrubs, the leaf mulch on the floor and the plants that
live in tandem with the trees belong to the forest ecosystem. It also
includes the animals that live in the forest. For example, birds nest in the
trees of a forest, members of the fungus kingdom grow on the forest floor,
and a variety of insects and mammals also take up their homes in a fo rest.
Thus a forest ecosystem is a community of organisms that lives within a
forest. Forest ecosystems are very important as they are the lungs of the
world. The forests release oxygen. Forest ecosystems are very rich and
diverse.
There are various type s of forest ecosystem throughout the world. Types
of forest ecosystem are as follows:
i. Rainforests:
Rainforests is one of the most biodiverse ecosystems on the planet.
Rainforests are often based around rivers. Amazon is an important
example. The north -eastern part of India is rich in rainforests.
ii. Mangroves:
Mangroves are a unique mix of trees and tidal swamps.
iii. Inland forests:
Innumerable mainland animals and birds like foxes and owls are found in
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20 iv. The Taiga:
The taiga is the name for the sparse forest right towards the polar regions
of the world.
v. Lakeside forests:
Lakeside forest ecosystems are very humid. Water birds and other water
wildlife can be found here.
vi. Mountain forests:
The forests that grow on mountains like mountain pines create Mountain
forests ecosystems like the Himalayan mountain forests in India.
 Characteristics of forest ecosystem are discussed below.
a. Seasonality: In countries that have seaso nal climates, forest
ecosystems will change with the seasons.
b. Deciduous or evergreen: A forest may be deciduous or evergreen,
or it may be a mix of both deciduous and evergreen trees.
c. Different levels: Some forest ecosystems feature several distinct
levels – such as the forest floor, the lower canopy, the upper
canopy and the tree tops, such as rain forests.
d. Attractive to birds and insects: as they make their homes in forests.
e. Homes for humans.
f. Protect the Earth from desertification by providing a shield ag ainst
winds.
2.3.2 Grassland ecosystems
The grassland ecosystems are composed largely of wide swathes of grass
rather than trees or shrubs. A grassland ecosystem is a community of
creatures such as various types of grasses, insects, and animals, etc. livi ng
together within a grassy space. Grassland ecosystems are extremely bio -
diverse and are home to thriving communities of plants, animals, insects
and mammals. Grassland ecosystems are present in every single continent
on this planet with the sole exceptio n of Antarctica, which is too cold to
sustain a grassland ecosystem.
 Grassland ecosystems can be found throughout the world, for example:
a. In the tropics near to the equator.
b. In the temperate zones of the earth, between the equator and the polar
Regions.
Grassland ecosystems are found in many shapes and sizes. However,
climate change, intensive farming and urban sprawl are all threatening our
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21 2.3.3 Desert ecosystem
A desert is a place that is difficult to inhabit. A desert e cosystem is a
community of organisms that live together in an environment that seems
to be deserted wasteland. Desert ecosystems can be hot as found in the
sandy Sahara or cold as on the peaks of mountains. Both in hot and cold
deserts it is difficult for organisms to inhabit. A desert ecosystem
generally witnesses little rainfall, resulting in less vegetation.
 In a desert ecosystem following things may be observed.
i. Numerous insects living in communities.
ii. An abundance of plant life.
iii. Mammals an d birds.
iv. Micro organisms such as bacteria are also present in this ecosystem.
 There are so many different types of desert ecosystems. Types of
desert ecosystems are stated under.
1. Hot deserts :
Hot deserts, for example Sahara, are found close to the equator. The plants
and animals that live here have evolved in order to adapt to very hot
conditions present over there.
2. Cold deserts :
When desertification exists at high altitudes the desert will be cold. A cold
desert may be sandy or rocky. Here org anisms have adapted the harsh
environment to survive.
3. Ice deserts :
Ice deserts are another type of cold desert. This is an uninhabited region
that is composed of ice. Ice deserts can be found towards the north and
south poles of the planet.
2.3.4. Fre shwater Ecosystems
Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They
include lakes and ponds, rivers, streams, springs, and wetlands.
 Freshwater ecosystems include:
a. sluggish waters of lakes and ponds
b. moving waters of rivers and s treams
c. Wetlands which are the areas of land periodically covered by water.
a. Ponds and Lakes Ecosystems – Lakes are large bodies of freshwater
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22 by land. Lake Baikal is the biggest la ke on Earth and contains about one
fifth of the Earth’s freshwater. Most of the time they include various types
of plants, amphibians and insects and fishes.
b. River Ecosystems – Rivers always link to the sea so they are more
likely to contain fish alongs ide the usual plants, amphibians and insects.
These sorts of ecosystems can also include birds because birds often hunt
in and around water for small fish or insects.
 There are 3 main groups of organisms in the freshwater ecosystem:
i. Plankton - organisms that float near the surface of the water
ii. Nekton – free-swimming organisms
iii. Benthos – bottom -dwelling organisms
Freshwater ecosystems are the smallest of the three major classes of
ecosystems, accounting for just 1.8% of the total of the Earth’s su rface.
The smallest living part of the food web of these sorts of ecosystems is
plankton, a small organism that is often eaten by fish and other small
creatures.
Marine Ecosystem
Earth’s largest aquatic ecosystems are the Marine ecosystems. Salt
marshes, intertidal zones, estuaries, lagoons, mangroves, coral reefs, the
deep sea, and the sea floor are included in the Marine ecosystems. They
can be contrasted with freshwater ecosystems, which have a lower salt
content. Marine waters cover two -thirds of the surface of the Earth and it
is the complex of living organisms in the ocean environment. Moreover
such places are considered ecosystems because the plant life supports the
animal life and vice versa. Marine organisms are not distributed evenly
throughout t he oceans. The availability of light, water depth, proximity to
land, and topographic complexity all affect marine habitats.
2.4 BIOSPHERE : CONCEPT, MEANING AND
COMPONENTS
What is Biosphere?
The Biosphere includes all the living components of the Earth. I t consists
of all plants and animals, including all the micro Organisms that live on
Earth and their interactions with the surrounding environment.
Most of the organisms exist in the lithosphere, the hydrosphere, and the
atmosphere. Many organisms move fre ely from one realm to the other. All
these together constitute the Biosphere.
What is Biosphere Conservation?
Since 1986, the Government of India has been implementing a programme
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23 propo rtions of 90:10 to the Northeastern Region States and three
Himalayan states and 60:40 to other states for the upkeep, improvement,
and advancement of certain components. The Central MAB Committee
reviews and approves the Management Action Plan drafted by the State
Government.
Zoning Schemes of Biosphere:
The zonation of each biosphere reserve in India or any other Biosphere
reserve should include:

Core area
Human int erference in the core area is restricted.
The core area of Biosphere Reserves generally consists of national parks
and sanctuaries protected under the wildlife protection act 1972.
Core areas of the biosphere reserve are securely protected sites for
conse rving biological diversity. Monitoring these minimally disturbed
ecosystems and undertaking non -destructive research and other low -
impact uses such as education.
In addition to its conservation function, the core area of the reserves
contributes to a rang e of ecosystem services, e.g. carbon sequestration,
supply of clean water and air, soil stabilization.
Buffer zone
Buffer zone generally surrounds or adjoins the core regions and can be
used for activities compatible with sound environmental practices, suc h as
environmental education, recreation, Ecotourism applied and basic
research.
The buffer zone of the biosphere reserve also has a critical connectivity
function in a larger spatial context as they connect biodiversity
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24 Buffer zones also have intrinsic functions of maintaining anthropogenic,
biological, and cultural diversity in the biosphere reserves.
Transition area
It is the outermost area of the Biosphere Reserves.
Transition Area plays a c entral function in sustainable development.
Transition Areas may contain a variety of agricultural activities,
settlements, and other uses.
Local communities, management agencies, scientists, NGOs, cultural
groups, and other stakeholders work together to manage and sustainably
develop the area’s resources.
2.5 BIOGEOGRAPHIC PROCESSES
Biologists and geographers come to biogeography from a broad
range of fi elds, naturally bringing with them discipline -specifi c
methods, assumptions, and goals, plus language, usually in the form
of jargon. Systematists have applied cladistics, one method used to
discover phy -logenetic relationships among organisms, to analyses of
area relation -ships using an array of methods, called by a v ariety of
names: vicariance biogeography, cladistic biogeography, historical
biogeography, phyloge -netic biogeography, phylogeography, and
comparative phylogeography, among others. Other systematists, in
contrast, document and interpret distribution patter ns without relying
necessarily on cladistic hypotheses, particularly in panbiogeography,
although these systematists rely.

(BIOGEOGRAPHIC PROCESSES)
invasion: when a species establishes itself in area that it was not found
previously.
modification: the change which takes place to an ecosystem as a result of
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25 succession: the change of species structure of an ecosystem over time.
A stable ecosystem that is functioning effectively and has a high level of
biodiversity could be said to be a climax community. This is an ecosystem
in its ideal state. The ecosystem is in stable equilibrium. This might mean
that even if there are small changes in the composition and number of
species, the ecosystem will continue to function more or less the same.
When ecosystems are disturbed or disrupted they are said to be in
disequilibrium. This means that the ecosystem will change in an attempt to
achieve the most ideal functioning. This process of ch ange involves the
process of invasion, modification and succession.
Intertidal wetlands provide an excellent example of invasion, modification
and succession.
Succession is a cumulative (build up of) change in the types of plants that
occupy in a particu lar place over time. Succession is a process of change.
There are a series of associated processes: colonisation, establishments
and extinction.
Colonisation is when a species spreads into new areas. It is also called
immigration.
Establishment refers to when a species becomes part of an ecosystem on a
permanent basis.
Extinction refers to the end of an organism or a group of organism. When
a species "dies out".
For succession to occur there usually has to be some kind of disturbance in
the environment. Th is disturbance will wipe out the majority of vegetation
in an area. A typical disturbance could be fire, logging or disease (these
may be relevant for mangroves) or severe flooding, pest infestation, or
climate change (these might be relevant for sea grass es). The disturbance
is a catalyst for change (this means it causes the change).
2.6 SUMMARY
The environment is the source of life on the earth and determines the
existence, growth and development of mankind and all its activities. The
interaction of human s with the environment (surroundings) in these
locations has often brought major changes in that environment. Some
changes were good, some were bad. The environment is a complex of
many variables which surrounds man as well as all living organisms. The
environment is complex, dynamic and systematic in nature. The biotic
components and abiotic components together make up the environments.
There exists man made environment that is helping man to lead a smooth
life.
Environmental geography is broadly experien tial so students have more of
a diverse learning experience. It will also help the students to understand
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26 to the environment. Thus they will develop cultural awareness. No matter
how modern and manufactured world we live in mankind will forever rely
on the environment.
The term ecosystem was coined by A.G. Tansley in 1935, who defined it
as “the system resulting from the integration of all the living and non -
living factors of the envi ronment”. Ecosystems maintain themselves by
cycling energy and nutrients obtained from external sources. There are
different trophic levels that exist in an ecosystem. The ecosystem of
different habitats is interrelated with one another. Important differen ces
among the various components that make up an ecosystem like of Forest,
grasslands, Desert, Fresh water and Marine tell us that ecosystems are not
just habitats for animals. Many human communities live in there all over
the world.
2.7 EXERCISE
1. Explain the types of ecosystems.
2. Discuss the concept of the Biosphere and explain the zones of the
Biosphere.
3. Discuss in detail the process of Biogeographic.
4. Explain the components of the Ecosystem.


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27 3
PLANT COMMUNITY
Unit Structure :
3.0 Objectives
3.1 Introduction
3.2 Concept of plant community and Classification of Plants
3.3 Biotic succession and climax vegetation
3.4 Major plant formation and biomes ­ Tropical
3.5 Major plant format ion and biomes ­ Temperate
3.6 Summary
3.7 Exercise
5.0 OBJECTIVE
1. Understand the Concept of plant community and Classification of
Plants .
2. know the Biotic succession and climax vegetation .
3. Learn about the Major plant formation and biomes ­ Tropical .
4. Understand the Major plant formation and biomes ­ Temperate .
5.1 INTRODUCTION
The association or group of plant communities of any region is called
vegetation. In other words, ‘all the plants which grow together in any area
form its vegetation, the character of which depends not just on the
different species present but on the relative propor­tions in which their
members are represented’. For example, two habitats may have similar
floras but their vegetation may vary from one another and two habitats
having diffe rent floras may have similar vegetation.
For instance, if there are two simi­lar habitats wherein both have grasses
and sal trees but there is overwhelming dominance of grasses and sparse
distribution of sal trees in the first habitat whereas the second ha bitat is
characterized by dense sal trees and sparse distribution of grasses, the
vegetation of the first habitat will be grasses whereas the vegetation of the
second habitat will be sal forest.
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28 3.2 CONCEPT OF PLANT COMMUNITY AND
CLASSIFICATION OF PLANTS
Meaning and concept of plant community:
The group or association of plants growing together in a particular habitat
is called plant commu­nity. In other words, ‘those plants which grow
together in a particular habitat are referred to as a plant commu­nity, by
which something more than a mere collection or assemblage is implied’.
‘A group of populations of different species living in the same local areas
and interacting with one another is called ecologi­cal community Plants
play very dominant role in the bi osphere because these are primary
producers in the biosphere and provide directly or indirectly food to all
terrestrial and aquatic animals including man. The social group­ings of
plant species are called plant community of which plant is the fundamental
basic unit. Plants directly receive and trap solar energy (light energy) and
prepare their own food with the help of sunlight through the process of
photosynthesis.
Thus, solar energy converted into the food or chemical energy is
transferred to differ­ent a nimals and micro ­organisms through different
trophic levels of food chain. Thus, plants are intermediary between biotic
and abiotic components of the environment/ecosystems/biosphere. On the
basis of importance and dominant role of plants in the biosphere the study
of plants is given more significance.The study of plants has been
developed as an important branch of geography which is called as plant
geography which includes the study of classification of plants, their
spa­tial distribution, origin and devel opment, dispersal and extinction and
functions.
The main functions of plants are to trap solar energy and prepare their
food with the help of photosynthesis and to circulate and transfer energy
and nutrients among the organisms of different trophic levels of the food
chain.
CLASSIFICATION OFPLANTS
Annuals :
Annuals are plants that complete their life cycle in one year. They
germinate, grow, bear fruits and die off within an year. Generally, all
herbs and plants belonging to the grass family exhibit this typ e of life
cycle. Mustard, watermelon, corn, lettuce wheat, are a few examples of
annual plants.
Lifespan of Rice Plant :
Rice is a type of grass and is the staple food for millions of people across
the world. It is an annual crop with an average lifespan o f 4 – 8 months. It
goes through three main stages before it is harvested – vegetative stage,
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29 Biennials :
Biennials are plants that complete their life cycle in two years. They
germinate, develop a root system, stem an d leaves in the first year. Later
in their second year, they yield flowers and bear fruit. A few herbs are also
classified as biennials, including spinach. Along with spinach and other
herbs, biennials also include carrot, cabbage, petunias radish, onions, etc.
Perennials :
Perennials are plants which complete their life cycle in more than two
years. Once they grow, they start to bear flowers, produce fruits, seeds and
the cycle continues for a longer period of time. They do not die after
bearing fruits bu t renew their parts, season after season. Along with a few
shrubs, trees are all classified into perennials. For Eg., tomatoes, ginger,
banana, mango, coconut, palm, banyan, etc.
3.3 BIOTIC SUCCESSION AND CLIMAX VEGETATION
1. Primary Biotic Succession:
Primary succession refers to developmental se­quence of vegetation in
those bare areas where there were no vegetation and animals earlier. Such
areas or sites may be newly emerged sea floor, cooled and solidified
basaltic surfaces due to recent lava flows, ex posed lake bed due to drying
of water, newly formed sand dunes, flood plains formed by recent alluvia,
heaps of debris accumulated by man, the areas of exposed rocks due to
melting of ice from the glacial areas, etc.
The initial sites for the primary succe ssional development of vegetation
may be of various types having varying environmental conditions as
referred to above but for convenience such site is being selected which is
of bare rock surface and does not have any earlier vegetation for the
explanatio n of primary suc­cession of vegetation.
Thus, primary succession of vegetation on a bare rock surface having no
prior vegetation and animals starts and is completed through the following
stages:
(i) The initial plant ­free site has relatively dry environment. I t does not
mean that the climate of this site is dry because the rocks of the
concerned site are bare and are devoid of any plant and therefore the
environment becomes relatively dry due to excessive evaporation
though the climate may be even humid.
The pi oneer plants are established upon the bare rocks of the initial
plant ­free site. The initial pioneer plants include mainly algae and
lichens because they easily stick to the bare rocks and can easily
adapt to the environmental conditions of the initial sit es whether
these may be hot, dry or cold.
(ii) Dust particles blown by wind settle down in the concerned habitat.
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30 lichens. Some of the lichens secrete acids which react with the
minerals of the rock s of that habitat resulting into dissolution of
some minerals. This process starts the process of pedogenesis (soil ­
forming processes) and thin veneer of soil is formed in due course of
time. The soil zone, though very thin in the beginning, is colonized
by micro ­organisms.
(iii) The formation of soils through rock weath­ering and soil ­organisms
continues and the thickness of soils continues to increase with time.
Consequently, a few soil ­living animals like mites, ants, spiders etc.
are evolved. This ‘sere’ of s uccessional development of plant
community is characterized by more soil ­living organisms, sporadic
plants and wide open areas devoid of any plant. This type of plant
community is called open community or pioneer community.
(iv) Secondary community of mosses re places the pioneer community of
algae and lichens in due course of time. The mosses spread over the
soils like thin sheets and thus soils are covered by the mosses.
Consequently, the moisture content of the soils is increased because
the moss ­cover retards evaporation.
New dense matting of mosses also provides organic matter to the
soils and thus the soils are enriched by the addition of organic
nutrients. Gradually and gradually seasonal and perennial grasses are
developed along with new groups of animals like nematodes, spring ­
tails etc. which are able to obtain their food from the seasonal and
perennial grasses.
The gradual develop­ment of grasses covers the whole area of the
concerned habitat and thus is developed a dense vegetation cover
which changes and modifies the micro ­climates of the concerned
habitat. The dense vegetation cover de­creases ground temperature
and sunlight at the ground surface but increases moisture content of
the soils because evaporation of moisture from the soil surface is
effec tively decreased due to shade provided by dense vegetation
cover.
The open community is now changed to closed community (which
means that no part of the concerned habitat remains without
vegetation, in other words, whole area of the habitat is covered with
vegetation). This is possible only when the environ­ment of the
concerned habitat is wet but if the environ­ment of the concerned
habitat is dry and the surface is of sandy desert, much area is still
open and devoid of vegetation.
(v) After the development of sere of closed community there begins the
competition among the plants for space, sunlight, water and
nutrients.

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31 There may be two alternative routes of competition among the plants e.g.:
(a) If the plants of the concerned habitat are of the same species, th ere is
competition for the aforesaid elements among the different members
of the same species and only the fittest plants survive during the
competition. Thus, the principle of survival of the fittest becomes
effective in the community develop­ment of plan ts. Such competition
is called intraspecific competition which means survival of the
strongest plants and elimination of weaker plants but the preser­vation
of species is maintained.
(b) If there are more than one species in the concerned habitat,
competition for getting space, sunlight, water and nutrients takes place
among the individuals of different species wherein the strongest and
most aggressive species establish dominance over the entire vegetation
community.
But if all the species of the concerned habi tat are equally powerful,
there is maintained a balance of power among different species inspite
of competition and the result is that all species are preserved and
maintained. Such competition is called interspecific competition. This
phase (sere) of comm unity development is domi­nated by herbaceous
plants and thus by herb commu­nity.
(vi) With the march of time there is developed large shrubs in the
concerned habitat and the herb community is dominated and replaced
by scrub com­munity. At this stage a very sig nificant development
takes place in that the seeds of flowering plants (phanerogams) are
brought from the neighbouring areas to the concerned habitat by
winds and given birth to trees in the otherwise shrub ­dominated
habitat.
The canopy of these scattered trees is much higher than the stratum of
shrubs. Thus, the vegetation community upto this stage (sere) is
mixed with lichens, mosses, grasses, shrubs and trees. This is called
forest commu­nity and the sere of this successional development of
vegetation co mmunity is called preclimax.
(vii) The final stage or ‘sere’ of the successional development of
vegetation community is character­ized by the development of giant
and very tall trees; the density of which increases rapidly and the
whole of the concerned habitat is covered with dense and tall trees.
The roots of such tall trees penetrate far deeper in the ground. The
soil zone attains its maximum depth and different horizons of the soil
profiles are well devel­oped. The soil zones are colonized by various
micro­or ganisms which decompose the organic matter and help in
the process of energy transfer.
The vertical stratification of plant community is well developed.
This final phase or ‘sere’ of the successional develop­ment of
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32 succession, climatic climax vegetation etc. which represents mature
ecosystem.
2. Secondary Biotic Succession :
Secondary succession refers to the develop­mental sequences of
vegetation in those areas which had vegetation cover earlier but now have
been ren­dered nude or bare due to destruction of vegetation (either partly
or completely) either by natural proc­esses (like lava flow, prolonged
drought, glaciation, natural widespread forest fires through lightning,
se­vere storms, catastrophi c floods etc.) or by human interferences (like
intentional burning of vegetation, massive land use changes, mass felling
of tress and overgrazing etc.).
It may be pointed out that such disturbed ecosystems or habitats still
contain mature soils and some or iginal vegetation and therefore the initial
stage or sere of secondary succession of plant community is quite different
from the initial stage or ‘sere’ of primary succession which starts on a bare
rocky surface, having no earlier plants and animals.
The t otal time required for the development of climax vegetation or
climax succession in the secondary succes­sion is much less than the time
taken for the develop­ment of primary succession.
An example of secondary succession may be given from the hill areas o f
north ­east India where jhuming or shifting cultivation is a common
practice. Under this cultivation, first forest is cleared from small areas
through burning and then the soil is cultivated for agricultural crops for a
few years. When the soil loses its fertility, that area is left out and new
areas are cleared of vegetation for cultivation.
The abandoned area or the old clearance is again colonized by vegeta­tion
through various stages and it attains climax veg­etation or climax
succession in a short per iod of time (a few years), because the sequence of
secondary succes­sion is more rapid than the primary succession due to
availability of mature soils.
When the vegetation community of any region is disturbed before
reaching its climax sere by human interf erences (through slow but long ­
term activities like deforestation or burning of vegetation etc.), the
resultant vegetation is called sub ­climax vegetation.
When the disturbances in the successional develop­ment of vegetation
continue for long time, stages of normal sere of the development of
vegetation do not take place but these ‘sere’ are deflected by those factors
which bring in disturbances in the successional development of vegetation.
The vegetation developed during the deflected sere persists so long as the
factors responsible for the disturbance remain active. Such deflected
climax is called plagioclimax and its various stages are called plagio sere.
After some time if the factors causing disturbances in the successional
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33 ineffective, then the environmental conditions of the concerned site or
habitat are changed, with the result new environmental conditions of the
habitat are unable to support and preserve the plagioclimax veg­etation.
Thus, new vegetation develops under new changed environmental
conditions in place of plagioclimax vegetation and the successional
develop­ment of vegetation community takes place under nor­mal sere.
3.4 MAJOR PLANT FORMATION AND BIOMES -
TROPICAL
What is Biom e?
The definition of a biome is best explained as a collection of all the plants
and animals living in an environment that shares common characteristics.
Biomes, however, not only include only plants and animals. They can also
be defined in terms of microo rganisms as well. The term used for
microorganisms is the microbiome. For microorganisms, the area
considered need not be as large as that considered for plants and animals.
They can be defined on a much lesser scale. For example, the term 'human
microbiom e' refers to all bacteria, viruses, parasites, fungi, and other
microorganisms living inside the human body.
A biota is defined as the complete collection of all the organisms living in
a geographical region or a defined time scale. The scale of the regio n or
the time considered can be as small as a local region or instantaneous time
scales. It can also be as large as the whole planet or complete span of life
on earth. All the biotas living on the earth build up the earth's biosphere.
Tropical Rain Biomes/ Forest:
Tropical rain forests are home to more species than all other land biomes
combined. The leafy tops of tall trees – extending up to 70 meters above
the forest floor – form a dense covering called a canopy. In the shade
below the canopy, a second l ayer of shorter trees and vines forms an
understory. Organic matter that falls to the forest floor quickly
decomposes and the nutrients are recycled.
 Abiotic factors: hot and wet year ­round; thin, nutrient ­poor soils
 Dominant plants: broad ­leaved evergre en trees; ferns; large woody
vines and climbing plants; orchids and bromeliads
 Dominant wildlife : herbivores such as sloths, tapirs, and capybaras;
predators such as jaguars; anteaters; monkeys; birds such as toucans,
parrots, and parakeets; insects such as butterflies, ants, and beetles;
piranhas and other freshwater fishes; reptiles such as frogs, Caymans,
boa constrictors, and anacondas
 Geographic distribution: parts of South and Central America,
Southeast Asia, parts of Africa, southern India, and nor theaster
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34 Tropical Dry Biomes / Forest:
Tropical dry forests grow in places where rainfall is highly seasonal rather
than year ­round. During the dry season, nearly all the trees drop their
leaves to conserve water. A tree that sheds its leaves dur ing a particular
season each year is called deciduous.
 Abiotic factors: generally warm year ­round; alternating wet and dry
seasons; rich soils subject to erosion • Dominant plants: tall, deciduous
trees that form a dense canopy during the wet season; drou ght­tolerant
orchids and bromeliads; aloes and other succulents
 Dominant wildlife: tigers; monkeys; herbivores such as elephants,
Indian rhinoceros, hog deer; birds such as great pied hornbill, pied
harrier, and spot ­billed pelican; insects such as termit es; reptiles such
as snakes and monitor lizards
 Geographic distribution: parts of Africa, South and Central America,
Mexico, India, Australia, and tropical islands.
Tropical Savanna Biomes :
Receives more seasonal rainfall than deserts but less than tropi cal dry
forests, tropical savannas, or grasslands, are characterized by a cover of
grasses. Savannas are spotted with isolated trees and small groves of trees
and shrubs. Compact soils, fairly frequent fires, and the action of large
animals such as rhinoce ros prevent some savanna areas from turning into
dry forests
 Abiotic factors: warm temperatures; seasonal rainfall; compact soil;
frequent fires set by lightning • Dominant plants: tall, perennial
grasses; sometimes drought ­tolerant and fireresistant trees or shrubs
 Dominant wildlife : predators such as lions, leopards, cheetahs,
hyenas, and jackals; aardvarks; herbivores such as elephants, giraffes,
antelopes, and zebras; baboons; birds such as eagles, ostriches, weaver
birds, and storks; insects such as t ermites
 Geographic distribution: large parts of eastern Africa, southern
Brazil, northern Australia
Desert Biomes :
All deserts are dry –­ in fact, a desert biome is defined as having annual
precipitation of less than 25 centimetres. Beyond that, deserts vary greatly,
depending on elevation and latitude. Many undergo extreme temperature
changes during the course of a day, alternating between hot and cold. The
organisms in this biome can tolerate extreme conditions.
 Abiotic factors: low precipitation, vari able temperatures; soils rich in
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35  Dominant plants: cacti and other succulents; creosote bush and other
plants with short growth cycles
 Dominant wildlife: predators such as mountain lions, grey foxes, and
bobcats; herb ivores such as mule deer, pronghorn antelope, desert
bighorn sheep, and kangaroo rats; bats; birds such as owls, hawks, and
roadrunners; insects such as ants, beetles, butterflies, flies, and wasps;
reptiles such as tortoises, rattlesnakes, and lizards
 Geographic distribution: Africa, Asia, the Middle East, the United
States, Mexico, South America, and Australia
3.5 MAJOR PLANT FORMATION AND BIOMES -
TEMPERATE
The term Biome was first used by Frederic E. Clements to represent plants
and animals of a given region or habitat.
Over time, scientists expanded and refined the definition of biomes and
related different concepts in new areas of ecology, and in 1963 Shelford
characterized the following biomes: tundra, coniferous forest, Deciduous
forests, grassland s, deserts. Later, ecologist Arthur Tansley created
another definition of the ecosystem, including biological processes, rather
than the definition of biome.
Common to all biome definitions is that biomes are distinguishable
according to the organisms and climate in which they live and that the
organisms within the biome share an adaptation to this particular
environment. Climate is one of the important factors that determines
which organisms can be found in which biome, and the factors that affect
climate are Latitude, geographic features, and atmospheric processes that
diffuse heat and humidity.
Temperate Grassland Biomes:
Characterized by a rich mix of grasses and underlaid by some of the
world's most fertile soils, temperate grasslands – such as plains and
prairies – once covered vast areas of the midwestern United States. Since
the development of the steel plough, however, most have been converted
to agricultural fields. Periodic fires and heavy grazing by large herbivores
maintain the characteristic pl ant community.
 Abiotic factors: warm to hot summers; cold winters; moderate,
seasonal precipitation; fertile soils; occasional fires
 Dominant plants: lush, perennial grasses and herbs; most are resistant
to drought, fire, and cold • Dominant wildlife: pr edators such as
coyotes and badgers ­­ historically included wolves and grizzly bears;
herbivores such as mule deer, pronghorn antelope, rabbits, prairie
dogs, and introduced cattle ­­ historically included bison; birds such as
hawks, owls, bobwhite, prair ie chicken, mountain plover; reptiles such
as snakes; insects such as ants and grasshoppers. munotes.in

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36  Geographic distribution: central Asia, North America, Australia,
central Europe, and upland plateaus of South America.
Temperate Woodland and Shrubland Biomes:
This biome is characterized by a semiarid climate and a mix of shrub
communities and open woodlands. In the open woodlands, large areas of
grasses and wildflowers such as poppies are interspersed with oak trees.
Communities that are dominated by shrubs are al so known as chaparral.
The growth of dense, low plants that contain flammable oils makes fires a
constant threat.
 Abiotic factors: hot, dry summers; cool, moist winters; thin, nutrient ­
poor soils; periodic fires
 Dominant plants: woody evergreen shrubs wi th small, leathery
leaves; fragrant, oily herbs that grow during winter and die in summer
 Dominant wildlife: predators such as coyotes, foxes, bobcats, and
mountain lions; herbivores such as blacktailed deer, rabbits, squirrels,
and mice; birds such as ha wks, California quail, western scrub jay,
warblers and other songbirds; reptiles such as lizards and snakes;
butterflies; spiders
 Geographic distribution: western coasts of North and South
America, areas around the Mediterranean Sea, South Africa, and
Australia
Temperate Forest biomes
Temperate forests contain a mixture of deciduous and coniferous trees.
Coniferous trees, or conifers, produce seed ­bearing cones and most have
leaves shaped like needles. These forests have cold winters that halt plant
growt h for several months. In autumn, the deciduous trees shed their
leaves. In the spring, small plants burst out of the ground and flower. Soils
of temperate forests are often rich in humus , a material formed from
decaying leaves and other organic matter tha t makes stheoil fertile.
 Abiotic factors: cold to moderate winters; warm summers; year ­round
precipitation; fertile soils
 Dominant plants : broadleaf deciduous trees; some conifers; flowering
shrubs; herbs; a ground layer of mosses and ferns
 Dominant wild life: Deer; black bears; bobcats; nut and acorn feeders,
such as squirrels; omnivores such as raccoons and skunks; numerous
songbirds; turkeys
 Geographic distribution: eastern United States; southeaster Canada;
most of Europe; and parts of Japan, China, a nd Australia
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37 Tundra Biomes
The tundra is characterized by permafrost, a layer of permanently frozen
subsoil. During the short, cool summer, the ground thaws to a depth of a
few centimetres and becomes soggy and wet. In winter, the topsoil freezes
again. This cycle of thawing and freezing, which rips and crushes plant
roots, is one reason that tundra plants are small and stunted. Cold
temperatures, high winds; the short growing season, and humus ­poor soils
also limit plant height
 Abiotic factors: strong w inds; low precipitation; short and soggy
summers; long, cold, and dark winters;. poorly developed soils;
permafrost
 Dominant plants: ground ­hugging plants such as mosses, lichens,
sedges, and short grasses • Dominant wildlife: a few resident birds
and mam mals that can withstand the harsh conditions; migratory
waterfowl, shore birds, musk ox, Arctic foxes, and caribou; lemmings
and other small rodents
 Geographic distribution : northern North America, Asia, and Europe
3.6 SUMMARY
The main functions of plants are to trap solar energy and prepare their
food with the help of photosynthesis and to circulate and transfer energy
and nutrients among the organisms of different trophic levels of the food
chain.Over time, scientists expanded and refined the definition of biomes
and related different concepts in new areas of ecology, and in 1963
Shelford characterized the following biomes: tundra, coniferous forest,
Deciduous forests, grasslands, deserts. Later, ecologist Arthur Tansley
created another definition of the ecosystem, including biological
processes, rather than the definition of biome.A biota is defined as the
complete collection of all the organisms living in a geographical region or
a defined time scale. The scale of the region or the time considered can b e
as small as a local region or instantaneous time scales. It can also be as
large as the whole planet or complete span of life on earth. All the biotas
living on the earth build up the earth's biosphere.human interferences
(through slow but long ­term acti vities like deforestation or burning of
vegetation etc.), the resultant vegetation is called sub ­climax vegetation.
When the disturbances in the successional develop­ment of vegetation
continue for long time, stages of normal sere of the development of
vegetation do not take place but these ‘sere’ are deflected by those factors
which bring in disturbances in the successional development of vegetation.
The vegetation developed during the deflected sere persists so long as the
factors responsible for the dist urbance remain active. Such deflected
climax is called plagioclimax and its various stages are called plagio sere.
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38 3.7 EXERCISE
1. Discuss in details of classification of plant community.
2. Explain the Biotic succession and climax vegetation.
3. What are the Bio mes? Explain the Tropical Biomes.
4. What are the Biomes? Explain the Temperate Biomes.


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39 4
MARINE BIOGEOGRAPHY
Unit Structure :
4.0 Objectives
4.1 Introduction
4.2 Marine Biogeography Meaning and concept
4.3 Types of ocean habitats
4.4 Biogeography of estuaries
4.5 Island biogeography
4.6 Summary
4.7 Exercise
4.0 OBJEC TIVE
1. Understand the Marine Biogeography Meaning and concept
2. know the Types of ocean habitats
3. Learn about the Biogeography of estuaries
4. Understand the Island biogeography
4.1 INTRUDUCTION
Biogeographic provinces, based on distinct floras and faunas, have been
recognized for over 150 years (Forbes,1859). These provinces represent
parts of the world that host unique biotas, both areas of recent
evolutionary innovation and refuges of ancient li neages that persist today.
Although impenetrable barriers are relatively uncommon in the sea,
boundaries between these provinces are frequently associated with
continents, sharp ecological gradients, or vast expanses of open ocean.
Three observations by Fo rbes (1859) still guide the field of marine
biogeography today: (1) each zoo -geographic province is an area where
new lineages arise and tend to mix with emigrants from other provinces;
(2) each species is created only once and individuals tend to expand th eir
range from their place of origin; and (3) to be under -stood, provinces, like
species, must be traced back to their origin in the past. The first global
characterization of marine biogeographic provinces was compiled in the
pioneering volume Stereography des Meres (Ekman, 1935), later updated
and translated into Zoogeography of the Sea (Ekman, 1953).Therein, Sven
Ekman described a series of large regions and subregions, in -clouding the
continental shelf, tropical, temperate, and polar waters, their separa tion by munotes.in

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40 zoogeographic barriers, and their endemism. Briggs (1974) divided the
continental shelves into series of large biogeographic regions that, in turn,
contained smaller biogeographic provinces, each de fined on the basis of
endemism. This work established the now -accepted practice oldening
biogeographic provinces on the basis of 10% endemism at the species
level within published species inventories, most frequently fishes or well -
known invertebrate groups such as molluscs. A central theme was that the
greater the proportion of endemic biota, the greater the
evolutionarysigni ficance of the province (Briggs, 1974).Marine
biogeography has seen a recent revaluationin the f ace of considerable
research over the past few decades.
4.2 MARINE BIOGEOGRAPHY MEANING AND
CONCEPT
Marine biogeography is the study of marine species, the geographic
distribution of their habitats, and the relationships between living
organisms and the en vironment. Creating a habitat ecosystem map of the
seafloor —a key component of marine biogeography —is a tricky process.
Marine biogeography is a subfield of the biogeography aimed at
understanding the patterns and processes governing the distribution of
marine taxa at geographic scales. Marine biogeography is related to
several disciplines and subdisciplines, including marine biology and
ecology, physical and biological oceanography, ecophysiology, genetics,
geography, geology, paleontology, and macroecolog y. Several
subdisciplines have been proposed from the intersection with these
branches, alluding to the subject of study (e.g., phytogeography and
zoogeography), the temporal scale of driving processes (e.g., ecological
biogeography and historical biogeogr aphy), the use of phylogenetic and
phylogeographic tools (e.g., comparative phylogeography),
paleontological data (paleobiogeography), or the combined use of multiple
approaches (e.g., integrative biogeography). Progress in marine
biogeography has historic ally been well behind terrestrial biogeography,
owing to the large logistical limitations involved in obtaining information
in remote areas, including the open ocean and the deep sea. However,
marine systems offer unique biophysical, environmental, and bio tic
features, creating a mosaic of phenomena and challenges unseen in
terrestrial biogeography. First, despite the fact that species richness seems
to be much lower in marine compared to terrestrial realms, phyletic
diversity is much higher in the sea. The re are thirty -five marine phyla,
compared to only eleven terrestrial phyla. Second, many marine organisms
possess complex life cycles, creating unique challenges to understanding
their biogeographic patterns and underlying processes. The possession or
lack of a planktonic larval phase seems to be an important (yet not the
unique) factor controlling the scale of dispersal, gene flow, size of the
geographic range, and duration in the fossil record. Third, seawater has
different biophysical properties than air , forcing different adaptations by
marine organisms. Finally, the marine fossil record is comparatively much
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41 robust comparative paleobiogeographic studies across the Phanerozoic,
and for testing the importance of evolutionary/historical factors shaping
present -day biogeographic patterns.
4.3 TYPES OF OCEAN HABITATS
Coral Reef Habitat :
From coral reefs to salt marshes, there are many different types of ocean
habitats to explore. So me of these are incredibly lively and filled with
thousands of well -known species, while others are dark, rarely explored,
and populated by some of the strangest creatures on Earth.Coral reefs are
incredible, diverse ecosystems found around the world. They are at
immediate threat from changing ocean temperatures and are often subject
to a process known as coral bleaching. They play host to diverse
inhabitants, including:
1. Hammerhead sharks
2. Tiger sharks
3. Sea turtles
4. Butterfly fish
5. Parrot fish
6. Rabbit fish
7. Mora y eels
scientists believe that coral reefs contain around 25% of all marine
species. Corals are, despite their appearance, living functioning marine
creatures themselves. They are soft -bodied organisms that attach to the
ocean floor and can live on their o wn or form large communities.
Estuaries Habitat:
Estuaries are partially enclosed bodies of water where fresh and saltwater
meet. They are regarding as transitory areas and are filled with marine
animals, as well as elements of the habitats described below . They play
host to many different bird species like the great blue heron, Canada
goose, American wigeon, and more. Crabs, small fish, oysters, otters, and
seashores can even be found in these areas.
Kelp forests
Kelp forests are highly diverse ocean habi tats that provide a home and
source of food for thousands of marine species. The kelp forests are giant
algae that grow into sheltered, underwater forests. They grow at incredible
rates, around eighteen inches a day, and are spread out along the west
coast of North America. Common animals found in and around kelp
forests include:
1. Great blue herons
2. Sea otters
3. Sea lions
4. Leopard sharks
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42 6. Sea urchins
7. Horn shark
8. California moray
9. California spiny lobster
Mangrove forests Habitat:
Mangrove forests a re groups of trees that live and grow in intertidal zones.
The majority of mangrove forests are in Asia, with the rest spread out
around the world. There are around 80 different species of mangrove all of
which require low -oxygen soil. They include the bla ck and red mangrove
as well as the loop -root and green buttonwood. It’s common to find
jellyfish, tunicates, molluscs, worms, barnacles, snails, crabs, shrimp, and
more in mangrove forests.
Mudflats Habitat:
Mudflats form in areas where the sea brings in s ilt and mud. They are
exposed during low tide and filled with invertebrates and other small
organisms. Also common to this ocean habitat are oysters, snails, and
worms. Many species of fish also frequent mudflats. They are found near
bays, lagoons, and mor e, around the world.
These meadows are underwater ecosystems that include flowering plants
that seed, have roots, and are anchored to the sea floor. The plants form
large meadows that are home to a diverse array of marine life. Endangered
species, like sea turtles and dugongs, feed there. They also provide homes
for shrimp, fish, and scallops, among many species of fish. Scientists
believe that the destruction of these habitats is incredibly detrimental to
the overall health of the Earth’s oceans.
4.4 BIOGE OGRAPHY OF ESTUARIES
Salt-wedge Estuaries
Salt-wedge estuaries are the most stratified, or least mixed, of all estuaries
(Molles, 2002; Ross, 1995). They are also called highly stratified
estuaries. Salt -wedge estuaries occur when a rapidly flowing river
discharges into the ocean where tidal currents are weak. The force of the
river pushing fresh water out to sea rather than tidal currents transporting
seawater upstream determines the water circulation in these estuaries. As
fresh water is less dense than s altwater, it floats above the seawater. A
sharp boundary is created between the water masses, with fresh water
floating on top and a wedge of saltwater on the bottom. Some mixing does
occur at the boundary between the two water masses, but it is generally
slight. The location of the wedge varies with the weather and tidal
conditions.
Fjord -type Estuaries
Fjords (pronounced fee -YORDS) are typically long, narrow valleys with
steep sides that were created by advancing glaciers. As the glaciers munotes.in

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43 receded they lef t deep channels carved into the Earth with a shallow
barrier, or narrow sill, near the ocean. The sill restricts water circulation
with the open ocean and dense seawater seldom flows up over the sill into
the estuary. Typically, only the less dense fresh w ater near the surface
flows over the sill and out toward the ocean. These factors cause fjords to
experience very little tidal mixing; thus, the water remains highly
stratified. Fjords are found along glaciated coastlines such as those of
British Columbia, Alaska, Chile, New Zealand, and Norway.
Slightly Stratified Estuaries
In slightly stratified or partially mixed estuaries, saltwater and freshwater
mix at all depths; however, the lower layers of water typically remain
saltier than the upper layers. Salin ity is greatest at the mouth of the estuary
and decreases as one moves upstream. Very deep estuaries, such as Puget
Sound in Washington State and San Francisco Bay in California, are
examples of slightly stratified estuaries. Even though Puget Sound is
classified as a fjord in terms of its geology, it does not exhibit the
characteristics of a fjord when classified by water circulation.
Vertically Mixed Estuary
A vertically -mixed or well -mixed estuary occurs when river flow is low
and tidally generated curre nts are moderate -to-strong. The salinity of
water in a vertically -mixed estuaries is the same from waters surface to the
bottom of the estuary. Strong tidal currents eliminate the vertical layering
of freshwater floating above denser seawater, and salinity is determined by
the daily tidal stage. An estuary's salinity is highest nearest the ocean and
decreases as it moves up the river. This type of water circulation might be
found in large, shallow estuaries, such as Delaware Bay.
Freshwater Estuaries
We nor mally think of estuaries as places where rivers meet the sea, but
this is not always the case. Freshwater or Great Lakes -type estuaries do
not fit the definition of a brackish water estuary where freshwater and
seawater mix.
Freshwater estuaries are semi -enclosed areas of the Great Lakes in which
the waters become mixed with waters from rivers or streams. Although
these freshwater estuaries do not contain saltwater, they are unique
combinations of river and lake water, which are chemically distinct.
Unlike brackish estuaries that are tidally driven, freshwater estuaries are
storm -driven. In freshwater estuaries the composition of the water is often
regulated by storm surges and subsequent seiches (vertical oscillations, or
sloshing, of lake water). While the Great Lakes do exhibit tides, they are
extremely small. Most changes in the water level are due to seiches, which
act like tides, exchanging water between the river and the lake.
Old Woman Creek is a freshwater estuary located on the south -central
shore o f Lake Erie in Ohio. Tidal changes in water level only average
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44 flow, a barrier sand beach will often close the mouth of the estuary,
isolating it from Lake Erie.
4.5 ISLAND BIOGEOGRA PHY
Island Biogeography
Islands are conventionally (and narrowly) referred to as isolated lands in
surrounding waters. However, in broad senses and when loosely defined,
‘islands’ also include insular areas or entities such as mountain tops, lakes
(e.g., p otholes in northern Great Plains in North America), oasis (in
deserts), and springs (especially in deserts) that support unique species
assemblages relative to surrounding habitats (e.g., Brown, 1978; Lomolino
et al., 2006). Mostly because of the insular n ature, habitats on oceanic
islands are often different from those on the nearest mainland even when
latitudes (climates) and the sizes (areas) are the same. For example,
islands often support unique species assemblages with proportionally more
rare and end emic species with small population sizes (e.g., reduced body
size or the so -called insular dwarfism and dispersal). Partly because of
their unique features (e.g., isolation) and conservation values, islands are
extremely attractive for intensive efforts in exploration, research, and
conservation (e.g., Kalmar and Currie, 2006). Island biogeography studies
the biogeography of the isolated units mentioned in the preceding text,
especially in the context of species diversity and related patterns and
ecological processes. As a major advance and guide in related research
arena on islands, MacArthur and Wilson (1967) developed the theory of
island biogeography (next section) based on observations of many earlier
naturalists made during their explorations around th e world. To date, this
relatively simple heuristic model has paved the ground and continues to
inspire many individuals for further exploration and in some cases has
resulted in with much greater effort and investment in such
research.Islands as ecological systems have suchsalient features as simple
biotas and variability inisolation, shape, and size. These characteristicsand
their large numbers facilitate both intensiveand extensive studies with the
repeatabilitynecessary for statistical validity. Since Darwin,islands have
provided particularly important andfruitful natural experimental
laboratories for developing and testing hypotheses on evolution,
biogeography and ecology. The theory of island biogeography has been
one of the moreimportant products o f island studies.Eugene G. Munroe
(1948, 1953) firstdeveloped the concept of an island having anequilibrium
species number when he examinedspecies -area relationships in his study
of the
4.6 SUMMARY
Marine biogeography is a subfield of the biogeography aime d at
understanding the patterns and processes governing the distribution of
marine taxa at geographic scales. Marine biogeography is related to
several disciplines and subdisciplines, including mari ne biology and
ecology, physical and biological oceanography, ecophysiology, genetics,
geography, geology, paleontology, and macro ecology. Several munotes.in

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45 subdisciplines have been proposed from the intersection with these
branches, alluding to the subject of stud y (e.g., phytogeography and
zoogeography), the temporal scale of driving processes (e.g., ecological
biogeography and historical biogeography), the use of phylogenetic and
phylogeographic tools (e.g., comparative phylogeography),
paleontological data (pale obiogeography), or the combined use of multiple
approaches (e.g., integrative biogeography). Progress in marine
biogeography has historically been well behind terrestrial biogeography,
owing to the large logistical limitations involved in obtaining informa tion
in remote areas, including the open ocean and the deep sea. now-accepted
practice oldening biogeographic provinces on the basis of 10% endemism
at the species level within published species inventories, most frequently
fishes or well -known invertebrate groups such as molluscs. A central
theme was that the greater th e proportion of endemic biota, the greater the
evolutionarysigni ficance of the province (Briggs, 1974).Marine
biogeography has seen a recent revaluation in the face of considerable
research over the past few decades.
4.7 EXERCISE
1. Explain the concept of Mari ne Biogeography.
2. Discuss in details of classification of marine habitat.
3. What is the Estuaries Biogeography.
4. Write on Island Biogeography.


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46 5
BIODIVERSITY
Unit Structure :
5.0 Objectives
5.1 Introduction
5.2 Meaning and Types of Biodiversity
5.3 Importance of Biodiversity
5.4 Causes of Biodiversity Loss
5.5 Biodiversity conservation
5.6 Summary
5.7 Exercise
5.0 OBJEC TIVE
1. Understand the Meaning and Types of Biodiversity
2. know the Importance of Biodiversity
3. Learn about the Causes of Biodiversity Loss
4. Understand the biodiversity conservation
5.1 INTRUDUCTION
The well -being of our society depends on the resources provided by the
earth. Typically, resources are materials, energy, services, staff,
knowledge, or other assets that are transformed to produce benefit or
satisfaction of human beings. This is a neutral stuff until some technical
skills are found to extract it from nature. Therefore, in order to become a
resource, the thing or substance must possess two properties i.e.
functionality and utility. The exploitation of nature and natural resources
can be dated back tothe advent of mankind and the very start of
civilizati on. But the present increase in population along with industrial
growth has given rise to the unlimited use of resources. Thus, disrupting
ecosystems and exhausting resources.
Due to deforestation the world loses more than 23 million acres of forest
area e very year. Thus, we should try utmost toreverse deforestation and
protect the world’s remaining forestsintact. The plants and animals in the
bits of forest that remain become increasingly vulnerable, sometimes even
committed, to extinction. Water resources are playing considerable roles in
the socio -economic development of any region. Water issues affect us all
as it is estimated that below 900 million people lack reliable access of safe
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47 Release of mining waste scanal so affect habitats. Therefore, we should
take a conscious effort for the conservation and sustainable use of
resources. From a human perspective proper utilization of natural
resources will lead to the increase ofwealth and meet our needs. Froma
broader biologicalor ecological perspective, a resource satisfies the needs
of a living organism.
5.2 MEANING AND TYPES OF BIO DIVERSITY
Concept of biodiversity :
Our ecosystems provide uswith food, medicine, clean airand water,
recreation , and spiritual and aesthetical inspiration.Hence the human
species cannot exist without its surrounding ecosystems. Biodiversity is
the sum of all the different species of animals, plants, fungi and microbial
organisms living on Earth and the variety of h abitats in which they live.
5.2.1 Concept
Biodiversity is the contracted form of biological diversity that means the
variability among living organisms from all sources including, inter alia,
terrestrial, marine and other aquaticecosystems. This also inclu des the
ecological complexes of which they are a part as well as diversity within
species, between species and of ecosystems. Scientists estimate that more
than 10 million different species inhabit Earth.
Biodiversity being a broad term may be measured at a number of
organizational levels. Traditionally, ecologists have measured biodiversity
by taking into account both the number of species and the number of
individuals of each species. This is known as relative abundance. On the
other hand, biologists use different measures of biodiversity that includes
genetic diversity to preserve the biologically and technologically
important elements of biodiversity.
Biodiversity loss refers to the reduction of biodiversity due to
displacement or extinction of species.T he loss of a particular individual
species, especially ifit is not acharismatic specieslike the Bengal tiger,
may appear as unimportant to some people. However, the current
accelerated extinction rate means the loss of tens of thousands of species
within o ur lifetimes.
Scientists have discovered and named only 1.75 million species which is
actually less than 20 percent of those estimated to exist. This estimation
states that the greatest value of biodiversity is yet to be known. Most
biologists agree that m uch of Earth’s great biodiversity such as species of
plants, animals, fungi and microscopic organisms such as bacteria is
rapidly disappearing. So scientists are putting stress on their researches
and studying global biodiversityaiming at better understand ing and slow
the rate of loss.
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48 5.3 IMPORTANCE OF BIODIVERSITY
Benefits of biodiversity
The following are some of the benefits of biodiversity:
 Provisioning services such as food, clean water, timber, fibre and
genetic resources
 Regulating services such as climate, floods, disease, water quality and
pollination
 Cultural services such as recreational, aesthetic and spiritual benefits
 Supporting services such as soil formation and nutrient cycling
5.3.1 Types of biodiversity
 Biodiversity includes three main types:
i. diversity within species orgenetic diversity
ii. between species or species diversity and
iii. between cosystems or ecosystem diversity
Genetic Diversity
Genetic diversity means the total number of genetic characteristics in the
genetic makeup of a species. Every species on Earth is related to every
other species through genetic connections. Each individual species
possesses genes which arethe source of its own unique features. Therefore
the more closely related any two species are, the more genetic informati on
they will share, and the more similar they will appear. For example in
human beings the huge variety of people's faces reflects each person's
genetic individuality. While all species have descended from asingle,
common ancestor, species diverge and deve lop their own peculiar
attributes with time, thus making their own contribution to biodiversity.
 The two reasons for differences between individual organisms are:
a. The variation in thegene which all organisms possess and is passed
from one to its off spring ’s
b. The influence of environment neach individual organism.
Species Diversity
The diversity of creatures roaming in our Earth is absolutely astonishing.
Species diversity is defined as the number of species and abundance of
each species living with in a particular habitator a region. Species are the
basic units of biological classification. Hence are the normal measures of
biological diversity. The number of different species in a given area is
called species richness. So when we measure the species richness of a
forest, we will find 20 bird species, 50 plant species, and 10 mammal
species. Species endemism is another term that is used to measure munotes.in

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49 biodiversity by way of assessing the magnitude of differences between
species.
Abundance is the number of individua ls of each species. Species diversity
may be of small scale such as a forest or ofalarge scale such as the total
diversity of species living on Earth
Ecological Diversity
Ecological diversity refers to the number of species in a community of
organisms and the dynamic interplay between them. It is the variation in
the ecosystems found inaregion or the variation in ecosystems over the
whole planet. An ecosystem consists of organisms from many different
speciesliving together in
a region and their connections through the flow of energy, nutrients and
matter. Those connections occur as the organisms of different species
interact with one another. Measuring ecological diversity is difficult
because each of Earth’s ecosystems merges into the ecosystems around it.
5.3.2 Hotspots of Bio-diversity
There are places on Earth that are biologically rich but deeply threatened,
so we must take some effort to protect them. Hotspots of bio -diversity are
large regions that contain exceptional concentrations of plant endemism
and experience high rates of habitat loss. By the method Biodiversity
hotspots those regions of the world are identified where attention is
needed to address biodiversity loss. It also guides investments in
conservation. Theidea was first developed by Norma n Myers in 1988 to
identifytropical forest ‘hotspots’ characterized both by exceptional levels
of plant endemism and serious habitat loss. To trunk this crisis, we must
protect those places where biodiversity lives. It is observedthat species are
unevenly distributed around the planet. Certain areas have large numbers
of endemic species which are not found anywhere else. Many of the
searc h eavily threatened by habitat loss and other human activities. These
areas are the biodiversity hotspots. Currently, 35 biodiversity hotspots
have been identified. Most of them occur in tropical forests and represent
just 2.3% of Earth's land surface. Among them they contain around 50%
of the world's endemic plant species and 42% of all terrestrial vertebrates.
5.3.3. Biodi versity in India with emphasison Western Ghat
India is one of the12 megabiodiversity centres of the world.
The country is divided into 10 biogeographic regions such as:
1. Trans Himalay as
2. Himalayan
3. Indian desert
4. Semi -aridzone
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50 6. Deccan peninsula
7. Gangetic plains
8. North -East India
9. islands
10. coasts
The hill chain of the Western Ghats constitutes the Malabar province. It
runs parallel to the west coast of India. Biogeographically, the Western
Ghats represents 4% of India’s land region that experiences hig h torrential
rainfall as well as monsoon and tropical climate and high variation in wind
speed.All these features have marked this region as one of the ten bio -
geographic zones in India.
The Western Ghats is considered to be one among the hotspots in the
world. This bioregion is highly species rich. But it is constantly facing
severe threats because nearly 40% of the total number of species is
endemic. In a in a 17,000 sq. km strip of forest along the seaward side of
the Western Ghats in Maharashtra, Goa, K arnataka, Tamil Nadu and
Kerala there are 15,000 plant species with5, 000 endemics (33%), 4,050
plants with 1,600 endemics (40%) .
The rain forests of the Western Ghats exist in an environment where there
is considerable seasonality in distribution of the r ainfall. The high
altitudinal zone also gives rise to a kind of forest which has primarily
Lauraceous vegetation. Moreover the parent rocks in these areas have
given rise to soils which are rich in nutrients and have a very high
moisture holding capacity. All these elements have given rise to the
tropical rain forests of the Western Ghats which has diversity in vegetation
types.
Vegetation types such as Wet evergreen, Dry evergreen, Moist deciduous
and Dry deciduous are classified based on mean annual rainf all. Forest
tracts up to 500 m in elevation are mostly evergreen. This comprises one
fifth of the entire forest expanse of the Western Ghats. The forest regions
in the 500 -1500 m range are semi -evergreen. Whereas, low, medium and
high elevation wet evergre en forest types are distinguished by low
minimum temperature with increasing altitude. Among these there are two
major centres of diversity, the Agasthyamalai Hills and the Silent Valley
or New Amarambalam Reserve basin.
Flora and Fauna of the Western Ghat s
The area has an estimated 3,00,000 hectare (37%) under forest cover and
is characterised by a rich diversity of flora and fauna.
 Flowering plants : 7402 species off lowering plantsare known from
the Western Ghats. Recent studies have suggested that there could be
2300 species of flowering plants endemic to the Western Ghats.
 Amphibians : Over 117 species belonging to 21 genera are recorded in
the forests and coastal areas of this region, of which76% are endemic to
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51  Invertebrates : A large variety of insects including some ofthe
spectacular butterflies and moths occur in the dense evergreen highland
and lowland forests. It is estimated that India has over 1,400 species of
which the Western Ghats harbour nearly 320 species including 37
endemics and 23 others shared with Sri Lanka. The area is host to a
large variety of fresh water mollusca, some of which are specific to the
region.
 Fish: There is a wide variety of fish available from freshwater
montane, lowland river streams and water bodies as well as coastal
lagoonsand backwaters. Around218 species of primaryand secondary
freshwater fishes in the Western Ghats are found. About 53% of all fish
species (116 species in 51 genera) in the Western Ghats are endemic.
Sixteen out of 20species of Caecilians known in India occur in the
Western Ghats; all 16 being endemic.
 Reptiles : 157 species of reptiles are found in the Western Ghats.
Majority of the reptile species are snakes. Dense forests of the region
are the home of the King Cobra and Rock Python apart from other
smaller reptiles. In all 97 species, representing 36 genera (2 genera of
turtle/ tortoise, 20 snakes, 14 lizards) are endemic. Among the tortoises
the endemic cane turtle, and terrapin are found in the Western Ghats.
The marsh crocodile or mugge r was once widely distributed in swamps
and larger water bodies of the forested areas.
 Birds : About 508 species of birds occur in the Western Ghats (590 if
sub-species are included). Among them 144 are aquatic or coastal
birds. Nineteen species are conside red to be endemictothe Western
Ghats. Many end emic birds are exclusive to evergreen and Shola
forests.
 Mammals : 120 species of mammals are reported from the Western
Ghats of which, 14 are considered to be endemic to the Western Ghats.
The forests of the a rea have large herbivores such as gaur, spotted deer,
sambar, barking deer, elephant, etc. Carnivores are represented by tiger,
leopard, jungle cat, leopard cat, fishing cat, Malabar civet, brown palm
civet, small Indian civet, two species of mongoose and wild dog.
With rapid developmental activities, agricultural expansion and
uncontrolled human population explosion, there have been significant
declining trend in the diversity of both flora and fauna in the Western
Ghats. As per recent records, 496 plant species, 91 amphibians, 41
mammals, 22 birds, 8 fishes, 6 reptiles 300 and 3 insect species are
considered as threatened, asper IUCN Red Data List, in the Western
Ghats. Further, 51 species are critically endangered, 125 are
endangered and 127 are in vulne rable category.


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52 5.4 CAUSES OF BIODIVERSITY LOSS
5.4.1 Threat To Biodiversity - Causes
Some of the main threats to biodiversity are:
1. Human Activities and Loss of Habitat,
2. Deforestation,
3. Desertification,
4. Marine Environment,
5. Increasing Wi ldlife Trade and
6. Climate Change.
1. Human Activities and Loss of Habitat :
Human activities are causing a loss of biological diversity among animals
and plants globally estimated at 50 to 100 times the average rate of species
loss in the absence of hum an activities. Two most popular species in rich
biomes are tropical forests and coral reefs.
Tropical forests are under threat largely from conversion to other land -
uses, while coral reefs are experiencing increasing levels of over
exploitation and polluti on. If current rate of loss of tropical forests
continues for the next 30 years (about 1 percent per year), the projected
number of species that the remaining forests could support would be
reduced by 5 to 10 percent relative to the forest in the absence o f human
disturbance.
The rate of decline would represent 1000 to 10,000 times the expected rate
of extinction without deforestation by humans. Some studies suggest that,
globally, as many as one half of all mammal and bird species may become
extinct within 200 to 300 years.
Biodiversity loss can result from a number of activities, including:
(a) Habitat conversion and destruction;
(b) Over -exploitation of species;
(c) Disconnected patches of original vegetation; and
(d) Air and water pollution.
Over the com ing decades, human -inducted climate change increasingly
become another major factor in reducing biological/biodiversity. These
pressures on biodiversity are, to a large extent, driven by economic
development and related demands including the increasing dem and for
biological resources.
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53 Activities that reduce biodiversity, jeopardize economic development and
human health through losses of useful materials, genetic stocks, and the
services of intact ecosystems. Material losses include food, wood, and
medicines , as well as resources important for recreation and tourism.
Losing genetic diversity, like losing species diversity, makes it even more
likely that further environmental disturbance will result in serious
reductions in goods and services that ecosystems c an provide.
2. Deforestation :
Forest ecosystems contain as much as 80 percent of the world’s terrestrial
biodiversity and provide wood fiber and biomass energy as well as critical
components of the global cycles of water, energy and nutrient. Forest
ecosy stems are being cleared and degraded in many parts of the world.
3. Desertification :
Desertification and deforestation are the main causes of biodiversity loss.
Both processes are decisively influenced by the extension of agriculture.
The direct cost of d eforestation is reflected in the loss of valuable plants
and animal species. Desertification process is the result of poor land
management which can be aggravated by climatic variations. Converting
wild lands to agriculture often involves ploughing the soi ls which leads in
temperate regions to an average decline in soil organic matter between 25
and 40 per cent over twenty five years.
4. Marine Environment :
Oceans play a vital role in the global environment. Covering 70 per cent of
the earth’s surface, the y influence global climate, food production and
economic activities. Despite these roles, coastal and marine environment
are being rapidly degraded in many parts of the globe.
5. Increasing Wildlife Trade :
According to Nick Barnes, “Trade is another cause of biodiversity
depletion that gives rise to conflict between North and South.” Global
trade in wildlife is estimated to be over US $ 20 billion annually. Global
trade includes at least 40,000 primates, ivory from at least 90,000 African
elephants, 1 mill ion orchids, 4 million live birds, 10 million reptile skins,
15 million furs and over 350 million tropical fish.
6. Climate Change:
As climate warms, species will migrate towards higher latitudes and
altitudes in both hemisphere. The increase in the amount of CO2 in the air
affects the physiological functioning of plant and species composition.
Moreover, aquatic ecosystems, particularly coral reefs, mangrove swamps,
and coastal wetlands, are vulnerable to changes in climate.
In principle, coral reefs, the m ost biologically diverse marine systems, are
potentially vulnerable to changes in both sea level and ocean temperature.
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54 survive a 15 to 95 centimeter sea -level rise over the next centu ry, a
sustained increase of several degrees centigrade would threaten the long -
term viability of many of these systems.
5.5 BIODIVERSITY CONSERVATION
Definition of Biodiversity Conservation
“Protection, restoration, and management of biodiversity in order to derive
sustainable benefits for present and future generations.”. Or, it can also be
defined as, “the totality of genes, species, and ecosystems in a defined
area.”.
Conservation of Biodiversity
Biodiversity conservation refers to the protection, preser vation, and
management of ecosystems and natural habitats and ensuring that they are
healthy and functional.
 The three main objectives of Biodiversity Conservation are as follows -
 To protect and preserve species diversity.
 To ensure sustainable management of the species and ecosystems.
 Prevention and restoration of ecological processes and life support
systems.
Biodiversity Conservation Methods
Two types of methods are employed to conserve biodiversity. They are -
In situ conservation and
Ex-situ conservat ion.
Following are some of the ways through which Biodiversity can be
conserved:
 In-situ Conservation
 Ex-situ Conservation
In Situ Conservation
In Situ Conservation refers to the preservation and protection of the
species in their natural habitat. It means the conservation of genetic
resources in natural populations of plant or animal species. In situ
conservation involves the management of biodiversity in the same area
where it is found.
 In situ, biodiversity conservation has many advantages
 It preserves s pecies as well as their natural habitat.
 It ensures protection to a large number of populations. munotes.in

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55  It is economic and a convenient method of conservation
 It doesn’t require species to adjust to a new habitat.
Different methods of In -situ conservation include biosphere reserves,
national parks, wildlife sanctuaries, biodiversity hotspots, gene sanctuary,
and sacred groves.
It is defined as the conservation of species within their natural habitat,
where the natural ecosystem is protected and maintained.
 In-situ conservation possesses numerous advantages. Some of the
important advantages of in -situ conservation are as follows:
 It is a cost -effective and convenient way of biodiversity conservation.
 Various living organisms can be conserved at the same time.
 They c an evolve better and can easily get adapted to various
environmental conditions.
 In-situ conservation occurs in places like national parks, wildlife
sanctuaries, and biosphere reserves.
Biosphere Reserves
These are national governments nominated sites, lar ge areas (often up to
5000 square km) of an ecosystem where the traditional lifestyle and
natural habitat of the inhabitants of that ecosystem are protected. They are
mostly open to tourists and researchers.
Example - Sundarban, Nanda Devi, Nokrek, and Mana s in India.
National Parks
These are limited reserves maintained by the government for the
conservation of wildlife as well as the environment. Human activities are
prohibited in national parks and they are solely dedicated to the protection
of natural fau na of the area. They mostly occupy an area of 100 -500
square km. There are a total of 104 national parks in India, right now. The
national parks may even be within a biosphere reserve. These are small
reserves that are protected and maintained by the gover nment. Its
boundaries are well protected, where human activities such as grazing,
forestry, habitat, and cultivation are restricted.
Example - Kanha National Park, Gir National Park, Kaziranga National
Park, and so on.
Wildlife Sanctuaries
Wildlife Sanctua ries are protected areas meant only for the conservation of
wild animals. A few human activities such as cultivation, wood collection,
and other forest product collection are allowed here, but they must not
interfere with the conservation of the animals. T ourist visits are also
allowed in these areas. There are a total of 551 wildlife sanctuaries in
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56 human activities like timber harvesting, cultivation, collection of woods,
and other f orest products are permitted unless they interfere with the
conservation project. Recreation tourism is also permitted.
Example - Ghana Bird Sanctuary, Abohar Wildlife Sanctuary, Mudumalai
Wildlife Sanctuary, etc.
Biodiversity Hotspots
A biodiversity hotspo t are the areas of conservation where there is strictly
a minimum of 1500 species of vascular plants and a habitat that has lost its
70% cover. These are protected areas for various purposes where the
wildlife, inhabitant lifestyle, and domesticated plants and animals are
conserved. Tourist and research activities are allowed.
Example - The Himalayas, The Western Ghats, The North East, and The
Nicobar Islands.
Gene Sanctuary
Gene sanctuary is a conservation area reserved only for plants. India has
its only g ene sanctuary set up in Garo Hills of Meghalaya for the
conservation of wild species of Citrus. Plans to open more such
sanctuaries are underway.
Sacred Groves
Sacred Groves are conserved areas for wildlife protected by communities
due to religious belief s. It is mostly a part of the forest where its wildlife is
given complete protection.
Ex Situ Conservation
Ex Situ Conservation means conservation of life outside their natural
habitat or place of occurrence. It is the method in which part of the
populatio n or the entire endangered species is taken from its natural
habitat which is threatened and breeding and maintaining of these species
take place in artificial ecosystems. These artificial ecosystems could be
zoos, nurseries, botanical gardens, etc. The li ving environments are altered
in these conservation sites, so there are fewer survival struggles like
scarcity of food, water, or space. Ex -situ conservation of biodiversity
consists of breeding and maintenance of endangered species using
artificial enviro nments like zoos, nurseries, botanical gardens, gene banks,
etc. The competition for food, water, and space among the organisms is
low.
Advantages of Ex Situ Conservation Include
Essential life -sustaining conditions like climate, food availability,
veterin ary care can be altered and are under human control.
Artificial breeding methods can be introduced leading to successful
breeding and creating many more offspring of the species.
The species can be protected from poaching and population management
can be e fficiently done.
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Biodiversity
57 Gene techniques can be applied to increase the population of the species
and they can again be reintroduced into the wild.
Biodiversity Conservation Strategies
Conservation of Ecosystems - The intent of the conservation of
biodiversity is to provide long term viability to the ecosystems. It is to
make sure that ecological integrity is intact. The landscapes of the region
which have undergone historical or evolutionary deterioration can be
reinstated. The threats can be removed and the ecosy stems should be able
to continue with ecological processes.
Reverse the decline of species - According to this strategy, the aim of
conservation is to restore the population of declined species in a particular
ecosystem.
Conservation of all biological asp ects- This strategy aims at giving cover
and conserving food, livestock, microbial population, agricultural stock
including plants and animals.
Efficient utilization of natural resources.
Strict laws on deforestation and preventions of deforestation by eve ry
means.
Poaching and killing animals in the wild should be prevented.
Creating public awareness about conservation of biodiversity and its
importance.
Longer time and breeding activity of the animals are provided.
The breeding of species in captivity is reintroduced in the wild.
Genetic techniques are used to preserve endangered species.
2.6 SUMMARY
We use a variety of materials derived from the environment. Nature has
given us abundant resources in form of water, air, soil, wild animals,
metals, fossils , fuels etc. and man byhis technical skill and knowledge
using resource from the dawn of civilization. Resource is the ability to
perform the work of satisfying the needs or wants of human being.
Resource can be classified on the basis of their nature, dur ability,
ownership and distribution pattern. All the resources are derived from the
environment. Many natural resources are essential for human survival,
while others are used for satisfying human desire. Conservation is the
protection, improvement, and wi se use of natural resource to provide the
greatest social and economic value for the present and the future.
“Sustainable development is development that meets the needs of
thepresentwithoutcompromisingtheabilityoffuturegenerations to meet their
own needs” . On September 25th 2015, countries adopted a set ofgoals to
end poverty, protect the planet, andensure prosperity for all as part of a
new sustainable development agenda. Each goal has specific targets to be
achieved over the next 15 years. For the goals to be reached, everyone
needs to do their part : governments, the private sector, civil society and
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Biogeography
58 5.7 EXERCISE
1. What is Biodiversity? explain the types of biodiversity.
2. Define the term Biodiversity. What is the importance of biodiversity?
3. What ar e the causes of Biodiversity loss?
4. Write in details methods of biodiversity conservation.


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QUESTION PAPER PATTERN

Time: 3 hours Marks : 100 N.B. 1.All questions are compulsory and carry equal marks.
2. Use of Map Stencils is permitted.
3. Draw sketches and diagrams wherever necessary.
Q.1 Long answer question on Unit -I 20 Marks
OR
Long answer question on unit –I for 20 Marks or
Two short answer questions each 10Marks 20 Marks

Q.2 Long answer question on Unit-II 20 Marks
OR
Long answer question on unit –II for 20 Marks or
Two short answer questions each 10 Marks 20 Marks

Q.3 Long answer question on Unit -III 20 Marks
OR
Long answer question on unit –III for 20 Marks or
Two short answer questions each 10Marks 20 Marks

Q.4 Long answer question on Unit -IV 20 Marks
OR
Long answer question on unit –IV for 20 Marks or
Two short answer questions each 10Marks 20 Marks

Q.5 Long answer question on Unit -V 20 Marks
OR
Long answer question on unit –V for 20 Marks or
Two short answer questions each 10Marks 20 Marks munotes.in