Biological Diversity

Biodiversity The variety of species in a specific area. Easily measured by counting the number of species living in an area. Increases closer to the equator.

Why is biodiversity important? Organisms are interdependent. Populations have adapted to live together in communities. Brings stability to ecosystems. Humans depend on other species for food, respiration, medicine, and raw materials.

Extinction The disappearance of a species when the last of its members dies. Natural process, resulting in both mass extinction and background extinction (Loss of one species per million species per year). The current rate of extinction is much higher than this.

Endangered Species A species is considered to be endangered when its numbers become so low that extinction is possible.

Threatened Species The population of a species is said to be threatened when it is likely to become endangered.

Exotic Species New species introduced into an ecosystem, either intentionally or unintentionally. When introduced, exotic species are not as vulnerable to competition and predation as other species and can grow at a very quick rate. Exotic species often severely decrease the population size of species already present.

Habitat Loss One of the biggest reasons for decline in biodiversity. Examples: Rainforests and Coral Reefs

Habitat Fragmentation Separation of wilderness areas form other wilderness areas. Contributes to: Increased extinction of local species. Disruption of ecological processes. Increased risk of fire. Changes in local climate. New opportunities for invasions by introduced or exotic species.

Habitat Fragmentation The smaller the fragment is the less biodiversity it has. Geographic isolation can lead to genetic isolation.

Edge Effect The edge of a habitat or ecosystem is where one habitat or ecosystem meets another. The differing conditions which exists along the boundaries of a habitat or ecosystem are called edge effects.

Edge Effect Edges tend to have greater biodiversity because different habitats with different species are brought together, along with two different sets of abiotic factors. When an edge changes, animals might migrate from their current area to the new edge, bringing different species into contact with one another.

Habitat Degradation The damage of a habitat by pollution. Three types of pollution: Air Water Land

Air Pollution Pollutants can enter the atmosphere in many ways, including volcanic eruptions, forest fires, and burning fossil fuels.

Air Pollution Acid Precipitation Rain, snow, sleet, and fog with low pH values. Has been linked to the deterioration of some forests and lakes.

Air Pollution Acid Precipitation Sulfur dioxide from coal burning and nitrogen oxides from auto exhaust combine with the water vapor in the air to form acidic droplets of water vapor. This precipitation leaches calcium, potassium, and other nutrients form the soil leading to the damage and death of plants and trees. When added to the water cycle, acid rain also degrades lake ecosystems.

Air Pollution Ozone Compound consisting of three oxygen atoms. Found in the atmosphere between 15 and 35 km altitude. This layer of ozone absorbs ultraviolet waves from the sun, reducing the amount of radiation received by organisms on the surface.

Air Pollution Ozone The Antarctic ozone hole is a reduction of up to 60% in the ozone layer over some parts of Antarctica during the spring. (The ozone then increases over the summer.) This hole is caused by human-produced chemicals, such as chlorofluorocarbons. Smaller, seasonal reductions are seen over the Artic.

Water Pollution Degrades aquatic habitats in streams, rivers, lakes, and oceans. Examples: Excess fertilizers and animal wastes can be carried to waterways by rain. The increase in nutrients cause algal blooms (excessive growth of algae). As the algae die, they sink and decay, removing needed oxygen form the water.

Water Pollution Examples: Silt from eroded soils can clog the gills of fish. Detergents, heavy metals, and industrial chemicals can cause death in aquatic organisms.

Land Pollution Examples: The average American produces 1.8 kg of waste daily. Although some of this waste may decompose quickly, most trash becomes buried in landfills. Strict controls on landfills are designed to lessen contamination of groundwater. Use of chemicals, such as DDT can both harm organisms and lead to habitat degradation.

Natural Resources Parts of the environment that are useful or necessary for living organisms. Include sunlight, water, air, and plant or animal resources.

Conservation Biology Study and implementation of methods to protect biodiversity. Based on principles of ecology.

U.S. Endangered Species Act Became law in 1973. Illegal to harm any species on the endangered or threatened species list. Illegal for federal agencies to fund any project that would harm any organisms on these lists. This includes changing an ecosystem where endangered or threatened species live.

Convention on International Trade in Endangered Species (CITES) Established lists of species for which international trade is prohibited or controlled. Has been endorsed by more than 120 countries.

Captivity Small numbers of organisms are maintained by humans. Run into issues of space and money and the possibility of the loss of the ability to survive in the wild by the organism.

Reintroduction Programs Release of organisms into an area where the same species once lived.

Preserving Habitats Creation of natural preserves and parks to protect unique environments and provide habitats for many organisms. Has been an effective way to maintain high levels of biodiversity in small areas. U.S. established its first national park, Yellowstone National Park, in 1872.

Habitat Corridors Protected strips of land that allow the migration of organisms from one small protected area to another. Help avoid genetic isolation.

Sustainable Use Use of natural resources in ways that will benefit humans and still maintain the ecosystem.