Chapter 5 Biological Diversity and Conservation

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Chapter 5Biological Diversity and Conservation

• Sections 1 and 2
• Vanishing Species
• Conservation of Biodiversity

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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.

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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.

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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.

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Endangered Species

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

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Threatened Species

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

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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.

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Habitat Loss

• One of the biggest reasons for decline in
  biodiversity.
• Examples Rainforests and Coral Reefs

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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.

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Habitat Fragmentation

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

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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.

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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.

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Habitat Degradation

• The damage of a habitat by pollution.
• Three types of pollution
• Air
• Water
• Land

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Air Pollution

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

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Air Pollution

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

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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.

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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.

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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.

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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.

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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.

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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.

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Natural Resources

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

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Conservation Biology

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

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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.

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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.

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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.

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Reintroduction Programs

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

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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.

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Habitat Corridors

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

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Sustainable Use

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