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Chapter 6: Humans in the Biosphere
A. Renewable Resources: resources that can regenerate quickly and
can be replaced
Ex. Freshwater, trees
B. Nonrenewable Resources: resources that cannot be replenished
by natural processes
Ex. Fossil fuels
C. Importance of Biodiversity:
 Food (fruits, vegetables, meats, fish)
 Industrial products (woods, paper)
 Medicine (plants – aloe)
 Stability to the environment
1. Negative Impact on Biodiversity
a. Soil Erosion: loss of soil and nutrients effects
autotrophs
b. Deforestation or Habitat Fragmentation: loss of
forested areas or splitting up a habitat for human use
 Decrease in space and food available to
organisms
 Leads to soil erosion
 Increased competition
c. Pollution or Habitat Degradation:
1. Acid Rain: burning fossil fuels or
pollutants are trapped in the rain water
 damages leaves
 pollutes soil and water
 changes the growth rate of
organisms (increase or decrease),
disrupting food chains/webs
2. Global Warming: increase in the earth’s
temperature due to trapping of
greenhouse gases
 Causes a rise in water levels
threatening land organisms
 Melts ice caps (arctic organisms)
 Heats up oceans causing changes in
food webs
 Change in weather patters that will
disrupt food webs
3. Depletion of Ozone Layer: damage to
the atmospheric layer that protects the
earth from UV radiation
 due to pollution (CFC’s)
 increased risk of cancer
 decrease resistance to disease
 mutations in organisms
4. Biological Magnification: the amount of
pollutants trapped in the organism
increases as it is passed through the food
chain
 Chemicals are not released from the
body
 Remain trapped and poison the
organism
 Ex. Bald eagle (DDT)
d. Invasive/Exotic/Non-native Species: organisms
that are introduced to a new area from another area
 Take over the niche of native species
 No natural predators
 Overpopulate
 Ex. Zebra mussels
e. Demands on Wildlife
1. Threatened Species: a species whose
numbers have decreased rapidly
2. Endangered Species: a species that is
on the verge of extinction
3. Extinction: when the last members of a
species dies out
f. Resource Depletion: overuse of essential resources
 Pollution, habitat loss
g. Human Exploitation: killing, endangering, or
over harvesting organisms for human benefit
 Causes decrease in biodiversity, extinction
D. Conservation of Biodiversity
1. Habitat Corridor: connecting fragmented areas
 Increases food, reproduction, space
 Decreases competition
2. Reforestation: planting trees/autotrophs in place of those
that have been cut down
 Increases biodiversity
 Stable food chains
 Restores habitats
3. Captivity and Reintroduction Programs: protects
organisms that would die in the wild or who are
endangered and teaches those who have been
rehabilitated how to live in the wild
 Protects the few remaining
 Increases biodiversity
4. Laws:
a. Hunting: protects endangered species, helps balance
overpopulating species
b. Pollution: prevents the destruction of ecosystems
and biological magnification by restricting
the amount of pollution
c. Endangered and Threatened Species List: created
to protect organisms whose numbers have
declined from being killed and conserves
biodiversity
5. Recycling: reusing materials
 Conserves nonrenewable resources
 Decreases pollution
6. Biological Controls: using natural living organisms to
control overpopulating pest
 No use of pollutants
7. Seed Banks: placing seeds of threatened or endangered
plants in a protected “bank” for future use
 If the plants ever become extinct the seeds are
available for repopulating the species
8. Sex hormones/radiation: using hormones or radiation to
sterilize pest populations so they don’t reproduce
 Not polluting environment
 Only affects pest population
9. Parks, Preserves, and Protected Areas: areas that are set
up to conserve biodiversity
 Cannot be used for human exploitation
 Conserves biodiversity
10. Education of Ecology: knowing the demands and affects
on the environment allows us to make the
appropriate choices