Ecology

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Ecology
Biodiversity and Conservation
Textbook Chapter 5 Review Book Topic 6
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What is Biodiversity?

• The variety of life in an given area
• Determined by the number of different species
  present
• High biodiversity increases the stability and
  health of an ecosystem
• Three types
• Genetic diversity
• Species diversity
• Ecosystem diversity

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• Genetic diversity
• Variety of genes or inheritable characteristics
  (within DNA) that are present in a population
• Characteristic examples
• Color
• Resistance to disease
• Adaptability to the environment
• Within a population, genetic diversity ? the
  chances of survival during changing environmental
  conditions or threats of disease

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• Species diversity
• Number of different species and the relative
  abundance of each within a community
• Not evenly distributed across the biosphere
• Increases from the polar caps to the equator

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• Ecosystem diversity
• Variety of ecosystems within the biosphere
• Remember Ecosystems consist of the interacting
  population and the abiotic factors that support
  them
• All of the ecosystems on earth support a diverse
  collection of organisms

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Why is Biodiversity Important?

• Direct economic value
• Humans depend on plants and animals for food,
  clothing, energy, medicine, and shelter
• Preserving the organisms we use today is
  important to sustain our current way of life
• Humans must also preserve species which may be
  useful in the future

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• Some organisms we use today are not very diverse
  or capable of meeting our needs
• Closely related counterparts might be a better
  source to meet our needs
• Genetic engineering
• Ex. Corn versus teosinte
• Ex. Madagascar periwinkle, penecillian, and
  salicin

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• Indirect economic value
• Green plants produce oxygen which we breathe and
  recycle carbon dioxide
• Natural processes provide us with drinking water
• Ecological cycles of carbon, phosphorous,
  nitrogen, oxygen, etc.

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• Decomposers, climate
• regulators, fertile soil,
• protection against
• floods/droughts,
• Nature can provide
• services at less expense
• than using technology to
• provide the same service
• in some instances

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• Aesthetic (personal/emotional) and scientific
  value

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Threats to Biodiversity

• Extinction occurs when an entire species
  permanently disappears from the biosphere
• Past causes of extinction
• were natural gradual
• extinctions where new
• species evolved and
• biodiversity recovered after millions of years

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• The current high rate of extinction is due to a
  single species humans - who are changing Earths
  conditions faster than species can evolve to meet
  these changes
• 25 33 or all plant and animal species will
  become extinct within the next 100 years
• Current extinction rates are 1000 more than
  normal extinction rates of the past
• Most extinctions will occur near the equator and
  on islands

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? May 15, 1989
September 1914 ?
1937 ?
? 1651
Mammal List
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• Loss of Natural Resources
• All materials and organisms found in the
  biosphere
• Includes minerals, fossil fuels, nuclear fuels,
  plants, animals, soil, clean water, clean air and
  solar energy
• Species trying to cope with extinction (including
  evolving to meet these new conditions) do not
  have the natural resources they need

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• Habitat Loss (1)
• Destruction of habitat
• Has direct impact on biodiversity of the area
• Ex. clearing of land with bulldozers, fire,
  cutting down forests
• Disruption of habitat
• Habitat not destroyed but specific populations
  are affected
• Disrupts food web and all species in that habitat
• Ex. Over harvesting within fishing grounds

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• Overexploitation (2)
• Excessive use of species that have economic value
• Ex. American bison
• 50 million at one point
• Today, there are less than 1,000 left in the wild
• Ex. Ocelot, rhinoceros, tigers, elephants
• Hunted for pelts and body parts
• which are used to produce goods
• and medicine

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• Fragmentation of
• Habitat
• Separation of a
• habitat into smaller
• pieces of land

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• Forces populations to be confined to small
  habitats
• Many species will not cross man-made barriers
• Smaller habitat smaller populations
• Increases inbreeding and genetic problems in
  populations
• Less able to survive in changing environments or
  through disease

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• Pollution
• Changes the composition of the air, soil and
  water
• Some substances that are released into the
  environment (man-made or natural) are considered
  pollutants
• Pesticides
• Industrial chemicals
• Waste products

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• Biological magnification
• Increasing concentration of toxic substances in
  organisms as trophic levels increase in food
  chains/webs
• Producers low concentration
• Top consumers high concentration
• Ex. Pesticide DDT was used on plants to prevent
  bugs from eating the leaves but it almost lead to
  the extinction of the bald eagle

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• Acid precipitation
• Created from the burning of fossil fuels
• Releases sulfur dioxide and nitrogen oxide into
  the air
• When these gases react with water, sulfuric acid
  and nitric acid are produced
• Enters the water cycle in various forms of
  precipitation
• Affects soil, plants and animals

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• Eutrophication
• Form of water pollution that destroys underwater
  habitats
• Occurs when fertilizers, animal wastes or sewage
  flow into waterways
• Causes extreme algae growth which depletes the
  oxygen in the water and poisons the water
• Natural process but human activities have
  increased the rate at which it occurs

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• Invasive Species
• Nonnative species have been introduced to a
  habitat intentionally or by accident
• Population controls are not in place in these new
  habitats to regulate the effects of the
  introduced species
• Out compete, over populate and exploit the native
  species within the affect habitat

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• Estimated that 40 of extinctions since 1750 have
  resulted because of invasive species
• Billions of dollars are spent yearly to try to
  clean up or control the damage caused by these
  species
• Ex. Fire ants, purple loosestrife, zebra mussels

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Conserving Biodiversity

• Natural Resources
• An increase in human population increases the
  need and consumption of natural resources
• Not evenly distributed
• Developed countries have lower populations but
  higher consumption rates

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• Renewable resources are replaced naturally at a
  fast enough rate for continuous consumption
• Ex. Solar energy, agricultural plants/animals,
  water, air
• These resources are NOT unlimited
• If demand is higher than supply, resources can be
  depleted

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• Nonrenewable resources take extremely long
  periods of time to be renewed
• Ex. Coal, minerals, oil, extinct/endangered
  species
• Sustainable use is an approach where we use
  resources at a rate in which they can be replaced
  or recycled (preserving biodiversity and
  ecosystems)

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• Protecting Biodiversity
• Setting up conservation areas worldwide
• Ex. United States national park system
• Ex. 7 of the world is set aside for conservation
  purposes
• Focus conservation on biodiversity hotspots
• Create corridors between habitat fragments for
  safe travel and chances of genetic diversity

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• Restoring ecosystems
• Bioremediation is a technique where organisms are
  used to detoxify a polluted area
• Biological augmentation is a technique where
  natural predators are added to an ecosystem to
  control population sizes of other species

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• Legal Protection
• Since the 1970s, legal action to protect
  species, environments and the biosphere has
  increased
• Ex. United States (1973) Endangered Species Act
• Ex. Worldwide (1975) Convention on
  International Trade in Endangered Species of Wild
  Flora and Fauna (CITES)