Environmental Science

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Chapter 23

• Environmental Science

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23.1 Humans and the Environment

• Environmental science is the study of the
  relationships between humans and the Earth
• Since all life is interconnected,
• it is important to develop
• ways to correct global
• problems from humans

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A Global Connection

• Warming and cooling air form loops called
  convection cells in Earths atmosphere
• Convection cells determine
• climate and create
• oceanic circulation
• patterns

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Convection Cells

• The suns rays heat air molecules near Earths
  surface
• The less dense, warm molecules rise
• Eventually they cool and sink back toward Earth

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Upwelling

• Cold water rises from the ocean depths and
  carries nutrients upward
• More nutrients support more plankton which leads
  to large populations of fish

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El Nino

• Occurs when the warm surface water prevents
  upwelling from occurring
• Causes fish populations to decline (anchovy
  exports decrease)

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Declining Ozone

• O3 is a naturally occurring gas that protects
  living things from harmful UV rays
• CFCs are ozone-destroying chemicals

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Chlorofluorocarbons

• Used as coolants in refrigerators and air
  conditioners and as propellants
• Banned in 1992
• As long as we dont use CFCs, the ozone layer
  will continue to recover

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Increasing CO2

• Carbon dioxide is a byproduct of cellular
  respiration and a component of photosynthesis
• It is also released when fossil fuels are burned

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The Greenhouse Effect

• Greenhouse gases form a blanket around Earth and
  keep it at a temperature suitable for life
• When the layer gets thicker, it traps too much
  heat which causes global warming

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Evidence About Global Warming

• Ice-core samples show there is a correlation
  between rising
• temperatures and CO2
• concentrations
• Global temperatures are expected to rise 2C
  (4F) within the next century
• Can affect rainfall patterns, soil moisture, sea
  level, crop growth, biodiversity, human diseases,
  etc.

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Future Population Growth

• The U.N. estimates that human population will be
  at 12.5 billion by 2050
• This would result in more fossil fuels being
  burned and higher global temperatures

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23.2 The Biodiversity Crisis

• Biodiversity the variety of organisms in a given
  area
• Genetic diversity the amount of genetic
  variation (the most important measure of
  biodiversity)

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Measuring Biodiversity

• There are 3 million species that have been
  identified on Earth
• It is estimated that there are 10-30 million
  species
• Tropical rainforests have many undiscovered
  species

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Earths Biodiversity
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Extinction

• Extinction is forever!
• Rapid destruction of habitats is driving many
  species to extinction each day
• More than half of all tropical rainforests have
  already been destroyed

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Ways to Save Biodiversity

• Conservation strategies! (Ecotourism)
• Debt-for-nature swap richer countries or private
  organizations pay off some of the debts of a
  developing country in exchange for them not
  cutting down their rainforest

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The Importance of Biodiversity

• Utilitarian Value considers the economic
  benefits that biodiversity provides for humans
  (food, medicine, etc.)
• Nonutilitarian Value All life-forms deserve to
  exist (intrinsic value)
• Need for a Declaration of Interdependence

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Conservation and Restoration Biology

• Conservation biology identify and maintain
  natural areas to preserve biodiversity
• Restoration biology convert damaged areas back
  into viable habitats

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Conserving Migratory Birds

• Migratory birds spend spring and summer in Tundra
  and northern forests (abundant insects for food)
• In the Fall, they migrate to warmer climates
  where there will be enough food to last until
  their next breeding season

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Flyways

• There are four major flyways in North America

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Saving Critical Habitat

• Wildlife refuges must be established along the
  flyways to allow birds a place to rest and eat
  during their long migrations
• They also need protection in their wintering
  grounds
• Conservation efforts need
• to be international!

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Magee Marsh
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Reintroduction of the Wolf

• The gray wolf is an endangered species because
  they were killed by people
• There has never been a documented case of a human
  being attacked by a healthy wolf!
• They will occasionally kill livestock

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Wolves in Yellowstone

• Without wolves in the park, the elk population
  exploded
• In 1995, 14 wolves were released

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The Florida Everglades

• Drainage canals were built to divert water away
  from the everglades so people could use the land
  for homes
• More than 50 of the wetland was destroyed

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Wetlands

• Wetlands are important habitats for wildlife
• They also purify drinking water and help
  replenish groundwater
• Coastal wetlands prevent flooding and beach
  erosion

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Everglades Restoration

• Currently, a restoration plan is being
  implemented to remove some of the drainage canals
• 40,000 hectares (100,000 acres) will be set aside
  for protection
• Melaleuca trees will be cut
• down (non-native species)

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Get Involved!

• Learn about your local environment
• Get involved in your own community to preserve
  local biodiversity
• Recycle
• Urban ecology increasing biodiversity in heavily
  developed areas