Transcript 5.3 People`s Effect on the Environment

5.3 People’s Effect on the
Environment
Geography
Journal
Describe a park you are familiar with. Describe
the grasses, plants, bushes, and trees you
find there. Are there many kinds of plants?
Do you think that all of the plants in the
park were planted by people? Are there
any animals, insects or birds in the park?
If so, what do they eat? What things in the
park were put there by humans? What
would happen to the trees and wildlife if the
park were to be used as an airport?
Vocabulary
 Ecosystem—a place where living elements
depend on one another—an on nonliving
elements—for their survival
 Deforestation—South Americans need land
for farms, so they are cutting down the forests.
When the forests are gone, many plant and
animal specials become extinct, or die out.
 Habitat—places where humans and animals
live
 Acid rain—rain that carries dangerous
chemicals. The fossil fuels used by industries
and automobiles release chemicals into the air.
Vocabulary
 Ozone layer—a layer of gas in the upper
part of our atmosphere. The ozone layer
blocks most of the harmful ultraviolet rays
from the sun. They cause skin cancer in
humans.
 Global warming—a slow increase in the
Earth’s temperature. It may be caused by
gases like carbon dioxide that are released
into the air. They are called greenhouse
gases.
 Recycling.
 Danger to Land, Water, and Air
Desert birds cannot live in a rainforest
Grassland plants cannot survive in a desert.
Living things are tied to their ecosystems
If one part of an ecosystem changes, other
parts are also affected.
 Some changes can destroy an ecosystem
 The greatest loss of ecosystems is happening
is South America.
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 Rain forests cover more than 1/3 of the continent
 They are home for more species of plants and
animals than anywhere else in the world
 South Americans need land for farms, so they are
cutting down the trees
Summarize the Endangered
Species Act.
 Protecting Endangered Species
 Protecting animals
 Laws—Endangered Species Act. It gave the
government power to protect not only
species that might become extinct, but also
the places that they live.
 Today, the act protects almost 1,000 kinds
of living things in the US that are
threatened, or endangered.
How do humans endanger
environments and habitats?
 Extinction has many causes
 People may build houses or businesses on land
that is the habitat of particular animals or
plants.
 The air, soil or water my be too polluted for a
species of pant or animal to survive.
 Sometimes a species is hunted until it
disappears.
 The Endangered Species Act stops extinction.
 People disagree about the law.
 Some think humans should be allowed to use
natural resources as they need them.
 Others think people should stop doing things
that hurt other species
Summarize Acid Rain
 Factories and Acid Rain
 Acid rain is rain that carries dangerous
chemicals.
 The fossil fuels used by industries and
automobiles release chemicals into the
air.
 The chemicals combine with water vapor
in the air, making the rain as acid as
vinegar.
 Canada and the US now have laws to
reduce acid rain
Explain how dumping waste in the
ocean can kill a human.
 Rivers and Sewage Pollution
 People have always dumped waste products into
rivers, lakes and oceans.
 These wastes can harm or destroy living things
in the water
 They also endanger people.
 Water creatures take in substances from the
water. Little fish eat the creatures, big fish eat
the little fish, and animals and people eat the
fish. The substances pass from one living thing
to another. Some of these substances are
poisonous.
Describe how the atmosphere is damaged by
the industrial revolution.
 The Ozone Layer and Ultraviolet Rays
 1970s scientist discovered that CFCs
(chorofluorocarbons) were destroying
the atmosphere.
 The ozone layer is a layer of gas in the
upper part of our atmosphere. The
ozone layer blocks most of the harmful
ultraviolet rays from the sun.
 These rays cause skin cancer in humans.
 They also damage other forms of life.
What is the Montreal Protocol?
 Until recently, aerosol spray cans,
refrigerators, and air-conditioners used
CFCs.
 In 1987, many nations met in Montreal,
Canada, to discuss the ozone layer.
 They reached an agreement called the
Montreal Protocol, which said that
nations would limit their use of chemicals
that destroy ozone, including CFCs.
Compare the summer of 1995 New England with
the Summer of 2007 in the South.
 Global Warming
 The summer of 1995 in New England
was unusually hot and dry.
Temperatures stayed above 90 degrees
for weeks. Heat and drought caused
water shortages and killed crops.
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How do developing countries
impact global warming?
 Scientists feared this was the start of global
warming, a slow increase in the Earth’s
temperature.
 Global warming may be caused by gases like
carbon dioxide that are released into the air.
 They are called greenhouse gases. They are
released when fossil fuels burn
 These fuels produce most of the world's
electricity. They also run the world’s 550 million
cars, buses, and trucks.
 Developing countries produce these gases when
they burn forests to clear land and use wood for
heating and cooking
Questions
1. How do fossil fuels create pollution?
2. Why is global warming a problem?
3. What alternatives to fossil fuels are
scientists researching?
4. Explain why some species are
endangered. Why do people
disagree about preserving land for
them?
Homework
 Write a persuasive paragraph
explaining why fresh water should be
protected. Include facts to support
your reasons.