It is a presentation on Biodiversity. Main it focuses the overall importance of biodiversity in a brief.

1. Presented by,
Md. Galib Ishraq Emran.
Department of Environmental Sciences.
2015-16 Sessions.
Registration No: 41778.
Class Roll: 219.
Jahangirnagar University,
Savar, Dhaka-1342.
Email: mdgalibishraqemran@gmail.com

2. Biodiversity
“Biodiversity is the degree of variation of life forms
within a given ecosystem, biome, or an entire planet.”
The Convention on Biological Diversity (CBD) defines
biodiversity as:
"The variability among living organisms from all
sources including terrestrial, marine and other aquatic
ecosystems and the ecological complexes of which they are
a part; this includes diversity within species, between
species, and of ecosystems."
Biodiversity is a measure of the health of ecosystems.

3. Factors determining the
Degree of Diversity
Habitat stress
Geographical isolation
Dominance by one
species
Availability of ecological
niches
Edge effect
Geological history

4. Levels of Biological Diversity
From the definition three levels of biological diversity
has been identified:
1)Genetic Diversity
2)Species Diversity
3)Ecosystem Diversity
fourth level is
4) Molecular Diversity

5. Genetic Diversity
 Genetic diversity, the level of biodiversity, refers to
“The total number of genetic characteristics
in the genetic makeup of a species. It is distinguished
from genetic variability, which describes the tendency
of genetic characteristics to vary.”
 The genetic variability is essential for the healthy
breeding population.
 Genetic diversity at its most elementary level is
represented by differences in the sequences of
nucleotides (adenine, cytosine, guanine, and thymine)
that form the DNA within the cells of the organism.

6. Species Diversity
“Species diversity is an index that
incorporates the number of species in an area and also
their relative abundance. It is a more comprehensive value
than species richness.”
Humans have a huge effect on species diversity. The
main reasons are:
●Destruction, modification and fragmentation of habitat
●Introduction of exotic species
●Over harvesting
●Global climate change

7. Ecosystem Diversity
“Ecosystem diversity refers to
the diversity of a place at the level of
ecosystems.”
An ecosystem is the result of all the biological,
climatic, geological and chemical "ingredients" in a
particular area.
This total combination of factors gives rise to certain
kinds of plant and animal communities whose needs
can be met by interacting with all the other parts of
the system.

8. The Value of Biodiversity
• Biodiversity is one of Earth’s greatest natural
resources. When biodiversity is lost, significant value
to the biosphere and to humanity may be lost along
with it.
• Biodiversity is of immense value. It plays a very
significant role in enriching the soil, maintaining the
water and climate cycle, humidity precipitation and
recycling and conversion of waste material into
nutrients.
• Biodiversity’s benefits to society include contributions
to medicine and agriculture, and the provision of
ecosystem goods and services.

9. The value of biodiversity are following types:-
1.Scientific value
2.Ecological value
3.Economic value
4.Social amenity (pleasantness) value
5.Biophilic value
6.Transformative value
7.Intrinsic value
8.Spiritual value
9.Aesthetic value
Continue…………………

10. Causes of Biodiversity Losses
The Millennium Ecosystem Assessment (2005) reports
that there has been a substantial and largely
irreversible loss in the earth's biodiversity.
1)Habitat loss, degradation and Habitat fragmentation
2)Invasive species
3)Pollution
4)Population growth
5)Over-consumption or unsustainable use
6)Climate Change and other Cumulative impacts

11. 1) Habitat and Degradation
Habitat loss, alteration and fragmentation directly
affect the species that rely on the habitat that is being
changed.
Destruction of biodiversity rich areas like tropical
forests
Destruction of coral reefs and Wetlands
Ploughing of grasslands
Aquatic ecosystem is threatened
Pollution of freshwater streams, lakes, and marine
habitats

12. 2) Invasive species
“Invasive species are harmful non-native
species whose introduction or spread threatens the
environment, the economy and society, including human
health.”
Many invasive species reproduce rapidly and damage,
displace or destroy native species in our
forests, agricultural areas, wetlands and lakes and
rivers.
They mussel disrupts ecosystem composition and
structure, clogs water intake pipes, and affects public
beaches.

13. 3) Pollution
 Pollution is emitted in many different forms,
including atmospheric pollution, soil and water
pollution, pesticides, particulate matter, and heavy
metals.
 Acid precipitation, for example, has had a
significant impact on forests and industrial
pollutants such as DDT is known to have caused
significant declines in populations of many bird
species.
 Pollution can also disrupt ecological processes. For
example, scientists are now linking light pollution to
declines in migratory songbirds.

14. 4) Population growth
 Human population growth adds to the impact of
all the other causes because more people require
more space and more resources.
 There are now about 6 billion people on Earth,
more than twice as many as in 1950.
 While the rate of increase is slowing, it still adds
more than 90 million people each year.
 Habitats, even healthy ones, can support just so
many of anything, including people.

15. 5) Over-consumption or
Unsustainable Use
“Over-consumption is the harvest of
species at a rate higher than can be sustained by the
natural reproduction of the population.”
 In Sundarban, for example, Sundari and other trees
are cutting unsustainably and causes great damage
to the ecological balance and loss of a greater number
of animal species including birds and wild animals.
 The unsustainable fishing causes loss of untargeted
fishes.
 The hunting of birds causes loss of migratory and
indigenous birds.

16. 6) Climate Change and other
Cumulative Impacts
 Climate change is a major threat to the world's
biodiversity.
 The cumulative impacts of pollution, habitat
modification, the global redistribution of species
and over-harvesting place many ecosystems at
risk.
 These cumulative impacts cause alteration,
reduction and loss of ecosystem function,
populations and species, degradation, loss and
fragmentation of habitat. They also damage human
health.

17. Impact of loss of
Biodiversity
 Increased vulnerability of species extinction
 Ecological imbalance
 Reduced sources of food, structural materials,
medicinal and genetic resources
 Cost increase to the society

18. Biodiversity Conservation
 Conservation process remains chiefly concerned
with the use, preservation and proper management
of the natural resources (Biodiversity) of the Earth
and their protection from the destructive influences,
misuse, decay, fire or waste.

19. How do we Conserve
Biodiversity ?
To conserve biodiversity, we must
Protect individual species,
Preserve habitats and ecosystems, and
Make certain that human neighbors of protected areas
benefit from participating in conservation efforts
There are two main ways to conserve biodiversity.
They are as follows:-
1)Ex situ (out of the natural habitat).
2)In situ (within the natural habitat).

20. 1) Textbook of Environmental Studies by
Erach Bharucha, Universities Press,
India, 2005
2) http://en.wikipedia.org
Some References