Definition of biodiversity: the total of all the genetically based variation in all organisms in the biosphere.


In other words: the number of different species on the Earth.


Types of Biodiversity

1.Ecosystem diversity: the variety of habitats, communities and ecological processes in the biosphere.

2.Species diversity: number of different species in the biosphere. (to date more than 1.8 million species)

3.Genetic diversity: the sum total of all the different forms of genetic information carried by a particular species.


The greater the biodiversity, the more likely at least some of the organisms will survive a dramatic change in the environment.


Example: water has a normal pH of 7.0

Imagine that an environment only has a few types of organisms (low biodiversity) such as: fish A (tolerates pH 7.2-8.4) and fish B (tolerates pH 6.5-7.5).


Then pollution (acid rain) causes the water to become more acidic and the pH changes to 6.0. Both types of fish will die because they can not tolerate the new environment.

If you add more organisms to the environment (increase the biodiversity) then there is a greater chance that at least some organisms will survive the environmental changes due to pollution (more stable ecosystem).

Fish C tolerates pH 5.5-7.3ŕ will live

Clam A tolerates pH 6.1-9.3 ŕwill die

Crab A tolerates pH 5.7-8.0 ŕwill live

Algae tolerates pH 4.0-7.5 ŕwill live

Coral tolerates pH 6.3-9.0 ŕwill die


NOTE: Biodiversity is one of the Earth’s greatest natural resources. Biodiversity important to:

·     Medicine (provides medicines such as aspirin and antibiotics)

·     Agriculture (allows for selective breeding of crops)

·     Ecosystems (can influence the ecosystem’s stability, productivity and value to humans)


Threats to biodiversity:

1. altering habitats or habitat destruction

2. hunting animals for food or other products to the point of extinction.

3. introducing toxic chemicals into the food web (pollution).

4. introducing a new invasive species into a stable ecosystem.

5.climate change

NOTE: All of the above are examples of how human activity can alter an ecosystem.





Conserving biodiversity

1.Protection of individual species

2.Preservation of habitats and ecosystems. (also called conservation)

3.Make sure there are benefits to participating in the conservation efforts.