Biology Chapter 5 Biological Diversity & Conservation

5.1 Biological Diversity Biodiversity- the variety of species in a specific area Rainforests have high biodiversity (400+ species) Corn fields have very low biodiversity (2-3 species) Biodiversity increases as you get closer to the equator Tropical regions contain 2/3 of all land species on Earth

5.1 Importance of Biodiversity Decreased biodiversity can impact nature negatively: Loss of one species can increase the species that organism eats and decrease the species that consumes it Removal of predators can cause the prey population to reach the carrying capacity faster Increased biodiversity makes an ecosystem more stable There are more alternate food and habitat sources with more biodiversity, so it is easier to adapt

5.1 Importance of Biodiversity to Humans Humans are dependent on other organisms for food, building materials, oxygen, etc. Medicines are often made from plants The more plants, the more possible medicines Undiscovered medicines may never be discovered if the plants are destroyed Pest resistant or drought tolerant crops can be created by crossbreeding wild plants & food crops

5.1 Loss of Biodiversity Extinction- when all of a species dies Scientists estimate 1-10 species goes extinct each year naturally Humans are responsible for many times that number going extinct each year Endangered species- when numbers of organisms get so low that extinction is possible Threatened species- when an organism is at risk of becoming endangered

5.1 Threats to Biodiversity Habitat loss- habitats are often destroyed by humans, causing the organisms to move or die Habitat fragmentation- when wilderness areas are divided, usually by human interference Increases extinction of local species Disrupts ecological processes Increases risk of fire Allows for invasion of unwanted or exotic species Changes overall biodiversity

5.1 More Threats to Biodiversity Edge effects- different organisms live on the edge of habitats and have different conditions Habitat destruction changes the edge of an ecosystem Habitat Degradation- the damage to a habitat by pollution Water pollution-degrades aquatic habitats Land pollution- degrades land by trash or introduction of toxins to the soil, which move into the plants, and then the animals

5.1 Exotic Species New species are introduced into areas, sometimes on purpose, sometimes on accident These species often interfere with the niche of natural species, which disrupts the ecosystem Exotic species often quickly overpopulate an area and cause the native species to die out

5.2 Conservation Biology Conservation biology- the study and implementation of methods to protect biodiversity Natural resource conservation- focus on saving natural resources such as sunlight, water, air, soil, plants and animals Species conservation- focus on saving animal and plant species

5.2 Endangered Species The US Endangered Species Act was passed in 1973 to protect species that were at risk of becoming extinct This made it illegal to harm any of these species Harm includes damaging or removing other parts of the ecosystem where these species live The CITES (Convention on International trade in Endangered Species) protects endangered species in more than 120 countries around the world

5.2 Habitat Preservation The US has started numerous habitat conservation programs to ensure that species have a safe place to live National parks & preserves were created as part of this program Examples include Yellowstone, Big Cypress, Crater Lake, Big Bend & Sequoia National Parks Habitat Corridors have also been created that preserve migratory routes so animals can travel between wilderness areas

5.2 Involvement of Humans Sustainable Use- a philosophy that people use natural resources while still maintaining the ecosystem People do not use more than can be regenerated in the amount of time between harvests This prevents us from overusing a resource and causing it to become unavailable

5.2 Species Preservation Reintroduction programs- release organisms back into their natural habitat These organisms are often grown in captivity (held by people) This is most successful when organisms are reintroduced into a similar habitat to their original, but is not the original (the original is usually damaged)