3.3: Biodiversity
pg. 88
Biodiversity: the variety of species in an ecosystem.
Comparing Biodiversity
When an ecosystem or area contains a large variety organisms living within,
it is called biodiversity. Up to now only 1.5 million species have been
identified, Scientists estimate that there are approximately 5 to 50 million
species of organisms living on Earth. Canada may have 140 000 to 200 000
plant and animal species, of these only 71 000 have been identified.
Abiotic Factors and Biodiversity
The percentage of biodiversity is greatest at the equator, and decreases as
you move closer to the poles. Abiotic factors may contribute to this, the
tropics have a high temperature and more rainfall which can support more
biodiversity in the coral reefs and rainforests. In one species of tree scientist
have found 283 species of organisms, by comparison in one hectare of
deciduous forest land in Ontario may fewer then 15 species of organisms.
Benefits of Biodiversity
Biodiversity supports survival. Ecosystems with high biodiversity are
disturbed (diseases, droughts, and exotic species) there is a greater chance of
recovery, healthy and stable.
Protecting Biodiversity
Biodiversity is important to a healthy ecosystem and the best way to protect
this by human prevention of pollution, habitat destruction, and the
introduction of new species.
e.g: Coral reefs: Tourism is slowly destroying this ecosystem; broken or
damaged by boats, anchors, air tanks, gasoline, and oil spills damage the
coral reef colony. These areas need to be protect by humans, controlling and
monitoring boaters.
Check Your Learning:
Questions 1 – 4, pg. 89
Wrap Up:
- Most species on Earth have not been identified or studied.
- Biodiversity refers to the variety of species living in an ecosystem.
- Biodiversity is needed to maintain ecosystems stability.
- Loss of biodiversity makes an ecosystem more fragile.