Chapter 5

Vanishing species Biodiversity = Variety of life in an area –# of species Where is the greatest biodiversity? –Warm places more biodiversity than cold 163 mammal species in Canada 367 mammal species in US 439 mammal species in Mexico

If two identical climates, then the larger area typically has more biodiversity. General rules: –1) warmer areas have greater biodiversity –2) larger areas have greater biodiversity

Why is biodiversity important? –Life needs life –biodiversity brings stability to an ecosystem –Medicine –Genetic cross breeding can increase productivity in food and animals.

Threatened- Population of a species starts a rapid decline. Endangered- when a species # become so low that extinction is possible. Extinct- the disappearance of a species when the last of its members dies. –Can be local or world-wide –Can occur naturally or due to unnatural disturbances

Threats to Biodiversity Habitat Loss- –The biggest threat to biodiversity (natural and unnatural) –when habitats are gone the essentials of life for some organisms are gone as well.

Habitat Fragmentation- –The separation of wilderness areas –Fragmentation can occur when roads, buildings, etc. are expanded into undisturbed wilderness. –Fragmentation can occur naturally from flooding, mountain formation, etc.

Biotic Issues of fragmentation- –Lack of range to feed and breed –Lack of enough food –Lack of migration routes Abiotic Issues of Fragmentation- –Climate change (edge effect = different conditions at the edge of a biome then the middle) –Lack of water and mineral resources

Habitat degredation- damage to the habitat by pollution. –Water pollution- degrades aquatic habitats

Land Pollution- degrades land habitats. Can be…. –Trash –Chemicals –Other items

Introduction of Exotics (alien) species- The introduced species my out compete native species for resources.

Conservation Biology Conservation biology = a field of biology that studies methods and implements plans to protect biodiversity.

Legal protection –Endangered Species Act (1973) – law that made it illegal to harm any species on the endangered or threatened species list.

Preserving Habitats- Protecting whole ecosystems –National wildlife refuges, parks, grasslands, wilderness areas, forest, etc.

Sustainable use- strives to let people use resources of a wilderness area in ways that will not damage the ecosystem.

Habitat corridors- uses natural strips to connect small areas of habitat. –Allows for migration –Allows for a small area to “act” as a larger area ecologically

Reintroduction Programs- releasing an organism into an ecosystem where it once lived.

Captivity- organism held by people. (I.e. Zoos)