Thursday, February 24, 2011

What are the benefits of

biodiversity?

Why is GENETIC DIVERSITY important?

• Genetic Diversity supports species and population survival.

• Genetic diversity increases the chance that some members of a population will survive environmental changes.

• When a population shrinks in size, its genetic diversity decreases. Even if the population grows again in the future, its genetic diversity is still reduced.

Why is GENETIC DIVERSITY important?

• When a population is reduced to a few members, this creates a bottleneck of reduced genetic diversity.

• The genetic diversity of the population is greater before the bottleneck than after it.

Genetic Bottleneck

Why is SPECIES DIVERSITY important?Which food web is going to be more affected by the loss of the mouse from its ecosystem?

If there is greater species diversity in an ecosystem, then the ecosystem is stronger.

Ecosystem A Ecosystem B

Why is SPECIES DIVERSITY important?Which environment do you think is more likely to recover from a disease that enters its ecosystem?

Tropical Rainforest Arctic Tundra

Why is SPECIES DIVERSITY important?• Some species are so important, if you remove them

from the ecosystem, the entire ecosystem will collapse.

• Keystone species: a species that is critical to the functioning of an ecosystem.– Example: sea otters and kelp beds

Why is ECOSYSTEM DIVERSITY important?Ecosystems provide us with:

1. Oxygen2. Clean water3. Flood & Erosion control4. Climate control5. Toxin removal6. Medicine7. Food

Why is ECOSYSTEM DIVERSITY important?• About 25% of the drugs prescribed in the U.S. come

from plants (e.g. antibiotics to fight bacterial infections like strep throat and meningitis)

• Fewer than 5% of tropical forest plant species have been examined for their medicinal value.

Why is ECOSYSTEM DIVERSITY important?• Most of the food we eat originally came from areas of

high biodiversity.

Wrap-UpKnowing what you know about the importance of genetic and species diversity, which image do you think represents a better approach to farming? Explain your answer in the area at the bottom of the worksheet.

Wrap-Up

• Most modern farmers plant huge fields of one type of crop (like the image in the bottom right corner).

• This reduced biodiversity makes the crops more susceptible to disease and pests, so farmers have to use a lot of pesticides to protect their crops.

Rice Patties for 8th Period

Rice Patties for 8th Period