Humans in the Biosphere Chapter 6
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Transcript of Humans in the Biosphere Chapter 6
Humans in the Biosphere
Chapter 6
Dr. Donna HowellBiology IBlacksburg High School
Our Ecosystem• Human activities
that affect the biosphere are:– Hunting and
gathering– Agriculture– Industry– Urban
development
Hunting and Gathering• The hunger-gatherer
way of life makes relatively few demands on the environment.
• However, the use of technology does: guns, automobiles, tools, etc.
Agriculture• The Green
Revolution is an effort to create sustainable agriculture
• Purpose was to increase the world’s food supply
Agriculture• Ecological
challenges:– Pest control– Finding irrigation
water
Industrial Growth• Growth of
industry has led to problems:– Pollution of
air, water, and soil
– Need for energy
Urban Development• Problems associated
with:– Waste disposal– Consumes farmland
and natural habitats– Stress on animal
populations
Resources• Environmental goods
and services may be classified as– Renewable– Nonrenewable
Renewable Resources• Renewable resources
are those that can be regenerated or replenished in a reasonable amount of time.– Ex: land, forests,
fisheries, air, water
Nonrenewable Resources• Nonrenewable
resources are those that cannot be regenerated or replenished in a reasonable amount of time.– Ex: fossil fuels
Sustainable Development• A way of using
natural resources without depleting them, and of providing for human needs without causing long-term damage to the environment.
Land Resources• Plowing the
land removes roots that hold soil in place, causing erosion.
• Contour plowing reduces erosion.
Forest Resources• Deforestation is the
loss of forests by human activities.
• Leads to severe erosion.
• Replace trees, produce faster growing trees via breeding.
Fishery Resources• Overfishing is
harvesting fish faster than they can reproduce.
• Affects other species in lakes, streams, oceans also.
• Aquaculture, limits on catch
Air Resources• Condition of air
affects organism’s health.
• Smog, pollution and acid rain are problems
• New technology to control emissions
Freshwater Resources• Pollution of water
can affect our health• Includes waste such
as chemicals, sewage, fertilizers, etc.
• Conservation, protection via filtering
Biodiversity• Biodiversity is
the sum total of all organisms in the biosphere.
• One of Earth’s greatest natural resources– Provide drugs,
food, etc.
Biodiversity• Human activity
can reduce biodiversity by altering habitats, over hunting, adding waste, and introducing foreign species.
Biodiversity• Pollution greatly
reduces biodiversity.• DDT was a problem.• Rachel Carson wrote
about in “Silent Spring”
• Discussed biomagnification.
Biological Magnification• Biological
magnification is when concentrations of harmful substances increase in organisms in the higher trophic levels in a food chain.
Introduced Species• Invasive species
are those that are introduced into new habitats, and they reproduce quickly.
• Harm existing species, and alter niches.
Introduced Species• Zebra mussels
came over in 1980’s from Europe.
• Spread through Great Lakes and rivers.
• Driving other native species to extinction.
Data Gathering• Researchers
collect data on systems to help monitor effects of humans on environment.
• Two are ozone layer and global climate system.
Ozone Depletion• 20-50 km above Earth, O3 is found.• Protects us from harmful UV rays.• Scientists are finding a hole in ozone caused
by CFC’s.
Global Climate Change• Scientists are
concerned with global warming.
• Partially due to burning of fossil fuels.
• Ice caps melting, sea levels rising, could cause extinctions.
The End