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Introduction to Biodiversity
What is Biodiversity
• Bio = life
• Diversity = variety
• Biodiversity = variety of life on this planet
• Biodiversity can be defined as the “variety of life”.
✓ The term Biodiversity was first coined by Walter G. Rosen in1986.
Biodiversity, or biological diversity, is a term that refers to the number
of genes, species, individual organisms within a given species, and
biological communities within a defined geographic area, ranging from the
smallest ecosystem to the global biosphere. (A biological community is an
interacting group of various species in a common location.)
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What is Biodiversity
✓ The Convention on Biological Diversity (CBD) defines biodiversity as “the
terrestrial, marine and other aquatic ecosystems and the ecological complexes of
which variability among living organisms from all sources including, inter alia, they
are part; this includes diversity within species, between species, and of
ecosystems.”
✓ Thus, Biodiversity refers to the variety of forms. It also includes the genes they
contain and the ecosystem they form.
✓ It deals essentially with dynamic processes and increases when anew genetic
variation is produced and decreases on the loss of genetic variation and species
extinction.
Where is biodiversity found?
• Biodiversity is not evenly distributed, rather it varies greatly
across the globe as well as within regions.
• Biodiversity increases as you move toward the equator.
• Tropical regions contain two-thirds of all land species on
Earth.
• The richest environments for biodiversity all seem to be
warm places: tropical rain forests, coral reefs, and large
tropical lakes.
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Types of Biodiversity
Biodiversity
Ecosystem Genetic
Diversity Diversity
Species
Diversity
TO PROPERLY CATALOGUE ALL LIFE ON
EARTH, WE HAVE TO RECOGNIZE NOT ONLY
SPECIES DIVERSITY, BUT ALSO THE
GENETIC DIVERSITY THAT EXISTS WITHIN
SPECIES, AS WELL AS DIVERSITY AT THE
LEVEL OF ENTIRE HABITATS AND
ECOSYSTEMS OF ORGANISMS.
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Types of Biodiversity
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Types of Biodiversity
1. Genetic Biodiversity
• It refers to variation of genes within species. This variation can exist between different
populations of the same species as well as between individual within a population.
• Genetic diversity provides organisms and ecosystems with capacity to recuperate after
change has occurred.
• Thus genetic diversity is a level of biodiversity that 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 a genetic
characteristics to vary.
• Genetic diversity plays a great role in the adaptability and survival of a species. A
species that has a large degree of genetic diversity among its individuals will have more
variations from which to choose the most fitting allele.
Types of Biodiversity cont.…….
2. Species Biodiversity
• Species diversity is a measure of the diversity within an ecological community that has
incorporates both species richness and the evenness of species abundance.
• Species diversity can be measured in the term of
I. Species richness which refers to the number of various species in a defined area.
II. Species abundance which refers to the relative numbers among species. For example, the
number of species of plants , animals and micro organisms may be more in an area than
that recorded in another area.
III. Taxonomic or phylogenetic diversity which refers to the genetic relationships between
different groups of species.
• Species diversity is not evenly distributed across the globe. The overall richness of species is
concentrated in equatorial to polar regions.
• In addition, biodiversity in land ecosystems generally decreases with increasing altitude.
• The other factors that influence biodiversity are amount of rainfall and nutrient level in soil.
• In marine ecosystems, species richness tends to be much higher in continental shelves.
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Types of Biodiversity cont.…….
3. Ecosystem or community Diversity
• Ecosystem diversity refers to the presence of different types of ecosystems.
• It is the structural and the functional unit of the biosphere.
• Ecosystem diversity is defined as,“ the aggregation of various habitats, community
types and abiotic environment in a given area.”
According to Whittaker (1965), the ecosystem diversities are of three types:
I. α Diversity: It refers to the species diversity in a given community. It depends
on species richness and species evenness.
II. Β Diversity: Its describes a range of communities due to replacement of
species which arises due to the presence of different microhabitats, niches
and environmental conditions.
III. γ Diversity: It describes diversity of habitat over a total and escape or
geographical area.
Importance of Biodiversity
A healthy biodiversity provides a number of natural services
for everyone:
Ecosystem services, such as
▪ Protection of water resources
▪ Soils formation and protection
▪ Nutrient storage and recycling
▪ Pollution breakdown and absorption
▪ Contribution to climate stability
▪ Maintenance of ecosystems
▪ Recovery from unpredictable events
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Importance of Biodiversity
Biological resources, such as
• Food
• Medicinal resources and pharmaceutical drugs
• Wood products
• Ornamental plants
• Breeding stocks, population reservoirs
• Future resources
• Diversity in genes, species and ecosystems
Importance of Biodiversity
Social benefits, such as
•Research, education and monitoring
•Recreation and tourism
•Cultural values
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