Environmental Sci Chap 1
Environmental Sci Chap 1
Environmental Sci Chap 1
Chapter 1 Notes
D.Knauss
RRHS
2006
Environmental Science
• study how humans interact with environment
(study how humans interact w/env.)
- major goal is to understand and solve environmental
problems
(GOAL- understand + solve env. Problems)
- study 2 main types of interactions between humans
and their environment
• how we use natural resources
• how our actions alter the environment
- an interdisciplinary science
Environmental Science
– one important foundation of environmental
science is ecology
Ecology
• study of how living things interact with
each other and their nonliving environment
- major fields of study that contribute to
environmental science:
- biology
- earth science
- physics
- chemistry
- social science
Ecology
• often the observations of nonscientists are
the first step toward addressing an
environmental problem
Hunter-gatherers
• people who obtain food by collecting plants
and by hunting wild animals or scavenging
their remains
- groups were small and migrated during
different times of the year based on food supply
- hunted bison
- set fires to burn prairies and prevent tree
growth
– helped spread plants
Hunter-gatherers
– rapid climate change and overhunting led to
extinctions of giant sloths , mastodons, cave
bears, and saber-toothed cats
Agriculture
• practice of growing, breeding, and caring
for plants and animals that are used for
food, clothing, housing, transportation, and
other purposes.
– started over 10,000 years ago and changed
society and the environment so much that it is
called the agricultural revolution
Agriculture
- humans populations grow at an incredible rate
- an area of land can support up to 500x as many
people by farming than by hunting and
gathering
- populations concentrated into smaller areas,
placed increased pressure on local
environments
– changed food we eat by creating domesticated
plants
Agriculture
- habitat destroyed using slash and burn
agriculture
– forest replaced by farmland causes soil loss,
floods, and water shortages
Industrial Revolution-
• involved a shift from water-, animal-, and
human-powered energy sources to fossil
fuels
– increased efficiency of agriculture, industry,
and transportation
– large-scale production of goods in factories
became less expensive than local production
– on the farm, machinery reduced the amount of
land and labor needed to produce food.
Industrial Revolution-
- Populations in urban areas grew as people
stopped growing their own food
- Motorized vehicles allowed food and goods
to be transported cheaply across long
distances
- Improved the quality of life….light bulb
- Agricultural productivity increased,
sanitation, nutrition and medical care
improved
Industrial Revolution-
- Pollution and habitat loss became more
common
- Artificial substances began to be used
which bring about their own sets of
problems
Closed system
• only the energy from the sun enters and the
only thing that leaves is heat
- potential problems involve some resources that
are limited and the fact that we will produce
more wastes than we can dispose of them.
- environmental problems can occur on different
scales: local, regional, or global
Closed system
- population growth increases, caused by
industrial and agricultural revolutions along
with modern medicine and sanitation
- human population almost quadrupled during the
20th century
– producing enough food has environmental
consequences—habitat destruction and
pesticide pollution
Closed system
- most scientists believe the population will
double before it begins to stabilize in the
21st century
Main Environmental Problems
Resource Depletion
• Natural Resource- any natural material that
is used by humans- 2 types
– Renewable- can be replaced relatively quickly
by a natural process
– Nonrenewable- forms at a much slower rate
than the rate at which it is consumed
Resource Depletion
• most common are minerals and fossil
fuels….could take millions of years to
replenish it
• depleted- a large fraction has been used up
Pollution
- a change in air, water, or soil that adversely
affects the health, survival, or activities of
humans or other organisms. Two main
types:
– biodegradable pollutants- pollutants that can be
broken down by natural processes
– nondegradable pollutants- pollutants that cannot
be broken down by natural processes
Loss of Biodiversity
- Biodiversity- refers to the number and
variety of species that live in an area
- Mass extinction- large-scale extinction
- Permian period, 95% of all species became
extinct
- Organisms that share the world with us can
be considered natural resources
Loss of Biodiversity
- Important to preserve organisms due to their
potential economic, ecological, scientific,
aesthetic, and recreational value.
“The Tragedy of the Commons”