Chapter 5: Biological

Diversity and Conservation

Biological Diversity (Biodiversity)

• variety of species in a specific area

• Ex. Farmland – dominated by one species of corn

• Rainforest – contains 400 species of plants

• areas around the world differ in biodiversity• biodiversity increases as you move towards

the equator• biodiversity is important – species are

interdependent• animals could not exist without green plants• plants are dependent on decomposers for

nutrients in the soil• Biodiversity brings stability – ecosystems are

stable if their biodiversity is maintained

Humans

• depend on plants for oxygen, animals for food, plants used for pharmaceuticals

Loss of BiodiversityExtinction – the disappearance of a species when the last of its members die

- natural process- rise due to

expanding needs of the human population

Endangered Species

• species is considered to be endangered when its numbers become so low that extinction is possible

Threatened Species

• when a population of species is likely to become endangered

• Ex. African

Elephants

Threats to Biodiversity

1. Habitat loss – land cleared in rain forests, coral reefs destroyed

• 2. Habitat Fragmentation – separation of wilderness areas from other wilderness areas

Found to contribute to:

• Increased extinction of local species• Disruption of ecological processes• New opportunities for invasions by

introduced or exotic species• Increased risk of fire• Changes in local climate• Wildlife areas that are broken up by

development

3.  Edge Effect - • different conditions along the edge of an ecosystem• where water meets land• where a field meets another field• edges tend to have greater biodiversity• edge changes, animals migrate to other areas

4. Habitat degradation - • the damage to a habitat by pollution• air, water, and land pollution• Acid precipitation – rain, snow, sleet, and fog

with low pH values– Have deteriorated some lakes and forests– Damages plant tissues, leaches nutrients

from the soil• Ozone Layer – absorbs UV rays striking the

atmosphere and reduce the Earth’s UV radiation– caused by pollutants – Chorofluorocarbons

(CFCs)

5. Water Pollution -

- degrades aquatic habitats – excess fertilizers and animals wastes

6. Land Pollution

• average American produces 1.8kg of solid waste daily – trash

• 657 kg – trash a year

• Land fills • Pesticides and

chemicals can also lead to land pollution

7. Exotic Species -

• people introduce a new species into the area

• species that are not native to a particular area

• once introduced, grow at an exponential rate b/c they are not vulnerable to predators

Conservation Biology

• the study and implementation of methods to protect biodiversity

• strategies based on principals of ecology

• natural resource conservation and species conservation

Natural Resources

• parts of the environment that are useful or necessary for living organisms– Sunlight– Water– Air– plant and animal resources

Legal Protection of Species

• US Endangered Species Act – became law in 1973

• Illegal to harm an endangered species• Includes changing ecosystem where

species lives

Preserving Habitats

• Habitat – physical location where an organism lives and interacts with its environment

• Natural reserves and parks

Habitat Corridors

• Habitat Corridors – protected strips of land that allow migration of organisms from wilderness area to another

•connecting protected areas with habitat corridors

•if the areas are separated, then interbreeding within populations occurs

People

• are needed to patrol parks• People are allowed to use resources: • Sustainable use: people are allowed

to use resources in a way that will benefit them and the ecosystem

Reintroduction

• release organisms into an area where the species once lived

• Ex. Black-footed ferret-• almost a lost species b/c they

feed on prairie dogs• prairie dog population was

destroyed by rural land use• ferrets - bred in captivity• then released back into the wild

Captivity

• organism that is held by humans

• Ex. Ginkgo tree – planted around temples, survived extinction when all other similar trees were destroyed

Protecting Plant Species

- ideal ways – allow to exist in natural ecosystem

• seed banks – save seeds incase plant ever becomes endangered