How do we impact our environmental systems? How do peoples actions
affect the environment? Are we slowly hurting our planet?
Human activities can affect the quality and supply of renewable resources
such as land, forests, fisheries, air, and fresh water.
What is the key?
Sustainability: a way of using natural resources without depleting them
while providing for human needs without causing long term
What are renewable and nonrenewable resources?
Renewable Resources: resources that can regenerate if they are living or
can be replenished by biochemical cycles if they are nonliving.
Foods (fruits and vegetables, meat from animals)
Nonrenewable Resources: resources that cannot be replenished by natural
Fossil fuels (coal, oil, gas)
Less Destruction of Earth (we don’t always need to drill into the planet)
Less Pollution (cleaner forms of energy like air and water)
Costs Less (sunlight is free the last time I checked)
Alternative Forms of Energy (solar, wind, geothermal)
The Other BIG 3
Coal (creates pollution and smog)
Oil (can get expensive……..glad I don’t drive a Hummer)
Natural Gas (Used to cook and heat homes but not easily
The problem with the big 3:
Time….we just don’t have enough of it!!!
Our impact on the Environment
Soil Erosion: the wearing away of surface soil by water and wind.
We add to this with the removal of trees (roots hold soil together)
Desertification: when farming, overgrazing, and drought combine to turn
once productive areas into deserts (usually happens in areas with dry
Deforestation: loss of forests (who do you think is guilty of this?)
Overfishing: harvesting fish faster than they can be replaced by
What can we do?
Proper management of soil
Humans need to control grazing and use proper farming techniques
Replanting trees and controlling the rate at which we cut down timber
Obeying the laws against catching fish that are protected (including size
and “out of season” factors)
Destruction of the Ozone Layer
The use of CFCs (chlorofluorocarbons use as propellants in aerosols
Water vapor (water vapor suppresses the formation of ozone)
What can we do?
In 1987, 46 nations signed an agreement called the Montreal Protocol. It
called for the immediate reduction of CFCs. The U.S. phased out the
use of CFCs in aerosol cans by the year 2000.
Reduce, Reuse, Recycle
Biodiversity: the sum total of genetically based variety of all organisms in
Ecosystem Diversity: the variety of habitats, communities, and ecological
processes in the biosphere.
Species Diversity: the number of different species in the biosphere.
Genetic Diversity: the sum total of all the different forms of genetic
information carried by all organisms in the biosphere.
What does all this mean to us?
Biodiversity is one of Earth’s greatest natural resources. Species of many
kinds have provided us with:
Threats to Biodiversity
Human activity can reduce biodiversity by:
Altering habitats (new construction by man means new home for wildlife)
Sometimes moving away spells the vanishing of the species.
Hunting species to extinction (Gorillas, Tigers, Jaguars, Eagles) Sometimes
other activities also endanger the species. We don’t hunt Pandas but we
deprive them of adequate bamboo. We don’t hunt Panthers but our close
proximity puts them in danger.
Introducing toxins into food webs (DDT was a pesticide used to kill insects
in agriculture. Cheap to use and was long lasting. The problem: it’s not
biodegradable and aquatic plants can’t eliminate it from their tissue.
Introducing foreign species into new environments(invasive species
reproduce quickly and take over because their regular predators are absent.
This takes away equilibrium from any ecosystem.
Conserving our Biodiversity
Conservation: the wise management of natural resources, including the
preservation of habitats and wildlife.
Zoos (breeding animals to later release them to the wild)
Marine Sanctuaries (protect our coral reefs and marine mammals)
Wildlife Reserves (Lacey Act of 1990: transporting of illegally killed
animals becomes federal crime)
A Healthy Biosphere
Our society depends on a healthy biosphere. We need our biosphere to
be healthy, diverse, and productive because we gain environmental
and economic benefits.
All life on Earth depends on climate conditions such as temperature and
rainfall. That's why many ecologists are concerned about strong
evidence that climate is changing.
Since the late nineteenth century, average atmospheric temperatures on
Earth's surface have risen about 0.6 Celsius degrees.
The term used to describe this increase in the average temperature of the
biosphere is Global Warming.
Is this trend due to a larger, natural cycle of climate change or are we
responsible for this?
What does the evidence say?
The most widely accepted hypothesis is that current warming is related, at
least in part, to human activities that are adding carbon dioxide and
other greenhouse gases to the atmosphere.
According to this hypothesis, the burning of fossil fuels, combined with
the cutting and burning of forests worldwide, is adding carbon dioxide
to the atmosphere faster than the carbon cycle removes it.
Possible Effects of Global Warming
Most recent computer models suggest that average global surface
temperatures will increase by 1 to 2 Celsius degrees by the year 2050.
What does this mean to us?
Sea levels may rise enough to flood some coastal areas.
Flooding would affect coastal ecosystems as well as human
More droughts during the summer growing season.
New organisms may be able to live in places where they once could not.
Other organisms may become threatened or extinct.
Let’s see how you’re doing
1. A large area of farmland has many different species of insects living
on it. Most of these insects are pollinators of the crops that grow on
the farm. If Ms. Robinson decides to plant one crop on all her
plots, what will be the result?
A. There will be less insect diversity.
B. The crops will be more likely to survive.
C. The crops will undergo genetic mutations.
D. The different insect species will interbreed.
Keep it up
2. A great deal of research is being done to make plastic wastes useful by
reusing the plastic for purposes other than the plastic's original use.
Which statement below best describes the impact reusing, rather
than recycling, plastics might have on our environment?
A. Natural resources can be conserved or made available for other uses.
B. More plastic will have to be produced to make up for the lost plastic
reused for something else.
C. Landfills will have new materials to dispose of, making the present
systems of disposing wastes obsolete.
D. The new plastic materials will be every bit as nondegradable as the
plastics they were made from, causing large amounts of wastes.
Did I mention that I like your smile?
3. Industries often spring up along major rivers, such as the Willamette
in Central Oregon. Some of these industries used PCBs (toxic, cancer-
causing chemicals), which are not biodegradable. If PCBs escaped
into the river in large amounts and entered the lower levels of the
food chain, what would be the likely outcome?
A. All species, except scavengers such as riparian crustaceans, would be
harmed by the PCBs.
B. Only the small fish and crustaceans that are most exposed to the
PCBs would be significantly harmed.
C. Over time, PCBs would collect in top predators such as salmon,
making them unsafe for human consumption.
D. The PCBs would become harmless as they break down over time with
exposure to the forces of nature and the environment.
Just a few more
4. An isolated community has a sunny climate with intermittent winds.
It is not located near the ocean or a large river. It wants to switch to a
renewable source of energy that creates the least air or water
pollution. Which energy source should they choose?
I’m so proud of you.
5. In the early twentieth century, kudzu (an Asian vine) was planted to
help control erosion in southeastern states. Presently, kudzu is
expanding at a rate of more than 120,000 acres per year. As kudzu
spreads, it dominates ecosystems, choking out trees and other plants.
Which choice correctly identifies kudzu’s role in an ecosystem?
A. invasive species
B. diversified species
C. indigenous species
D. carnivorous species
6. A team of scientists and Ms. Villalobos were studying glaciers in
Greenland and found that in the late 1900s a particular glacier on
Greenland's west coast started moving faster toward the sea, melting
more, and thinning. These changes are attributed to the warming
period Earth has been experiencing over the last 100 years. If this
warming trend continues, what could result?
A. a significant rise in sea level
B. an increase in the ocean's salt content
C. a significant decrease in ocean water temperature
D. the presence of icebergs farther from the polar caps
7. The number of pythons found throughout Everglades National Park
has increased in recent years. These huge snakes are not native to
Florida and are believed to have been released into the wild by pet
owners. Wildlife biologists have initiated attempts to capture and
remove these pythons. Which statement best explains the biologists’
reason for removing these pythons from the Everglades?
A. The pythons could upset the territorial boundaries of native
B. The pythons could adapt to overcome diseases common to native
C. The pythons could prey on native organisms and cause native
populations to decline.
D. The pythons could begin to interbreed with native snakes and
produce a more successful species.