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Chapter 3
Important Info
Definition of Environment
• All the conditions such as air, water and soil
that affect life; physical factors that influence
the existence or
development of
a living organism.
We have always lived in an
environment.
• Our environment has always met our
requirements. We used trees to make our
houses. We killed animals to eat. But now,
with technology and the ever increasing
population growth, we are using resources at
an unprecedented rate. We should consider
ourselves on “Spaceship Earth” ---the only
resources we have are the ones we have now.
Resource Management
• Managing our natural resources must become a
priority for us. We must take care of our
environment.
• Collecting data about the health of the ecosystem
will help us to know how to take care of our
environment. (See the Deer example on page
43.)
• If an ecosystem has been damaged (or polluted),
we must take steps to help it heal (or clean it up).
Resources
• Everything we use or could potentially use is a
resource.
• Nonexhaustible resources can last forever regardless of
human activities.
Ex: Sunlight, wind power, surface water.
• Renewable resources can be replaced by human
efforts. Ex: a forest, fish and wildlife. However, just
because it renewable doesn’t mean that it could be
around forever (if we use it too quickly, we could use it
up).
• Exhaustible resources (also called nonrenewable
resources)—they exist in finite amounts. Once we use
them up, they are gone. Ex: fossil fuels, soil.
Is nature balanced?
• No—nature is not balanced. It changes.
Balance implies no change. Some plant and
animal species become extinct, new species
are found. The overall temperature of the
atmosphere increases (global warming) and
decreases (ice ages).
As long as the
changes are slow,
we have time to adapt.
Carrying Capacity
• Population level—the number of given species
of plant or animal in a given area at a
particular point in time.
• Carrying capacity—the ability of an ecosystem
to provide food and shelter for a given
population level.
• When a population exceeds its ecosystem’s
carrying capacity, then diseases, predators, or
starvation reduce the population level.
Human Population
• Around 2000 years ago, the human population
of the world was about 300 million. Now we
are above 6 BILLION! See the graph on page
49.
• What is the carrying capacity for humans? Are
we there yet? (discuss)
Conservation and Preservation
• Conservation--the practice of protecting natural
resources against harm and waste. In
conservation, resources can be used, just not
overused or harmed.
• Preservation-- protecting natural resources just
for the sake of having them. Preservationists
would prefer that we leave these resources
alone.
• Multiple Use—a somewhat new idea…using our
resources so that we get more than one benefit
out of it. Using a lake for flood control, drinking
water and fishing, for example.
Biotechnology
• Scientists in this field are altering the genetic
makeup of living organisms to help
researchers in many fields, including medicine,
agriculture, and environmental sciences.
• Genetic engineering is one part of
Biotechnology. The genes of an organism are
modified to enable them to
do something or live longer
or prevent pests, etc.
• Is genetic engineering safe?
(discuss)
Pollution
• Water Quality-keeping water clean. There are
some laws that we’ll talk about in a chapter
down the road that helped us (forgive the
pun! ) “clean up our act” when it came to
water.
• Air Quality- acid rain,
smog (clouds of polluted air)
and car exhaust: all things
we should work on trying to
reduce to keep the air we
breathe clean!