copyright © by holt, rinehart and winston. all rights reserved. resourceschapter menu section 1 an...

Copyright © by Holt, Rinehart and Winston. All rights reserved.

ResourcesChapter menu

Section 1 An Interconnected PlanetChapter 22

22-1 Humans and The Environment

• The study of the interaction between humans and their own environment is environmental science.

• Humans, like all other organisms, depend on their environment for food, water, air, shelter, and other resources.

• The ability of humans to understand, manipulate, and possibly damage ecosystems exceeds that of other organisms.

• Therefore environmental science may be critical to our own survival.




Biodiversity• Biodiversity refers to the variety of life found in an area. A

measurement of Biodiversity is:– 1. Species richness refers to the number of unique species

in an area.– 2. Species evenness refers to the relative number of

individuals of each species in an area.• Another type of biodiversity is genetic diversity.

– Genetic diversity is the amount of variation within the genetic material of a given population (gene pool).

– Genetic diversity affects a population’s ability to adapt when faced with environmental change.

– Evolution by natural selection acts on genetic variation.




Valuing Biodiversity

• Scientists have named and described about 2 million species.

• Some believe there may be 100 million total species.



• Biodiversity provides important benefits to people.– Food.– Homes, fuel from trees.– Medicine and useful

chemicals.– Undiscovered species

may provide other benefits.

• Biodiversity provides important benefits to the survival of Earth.



Section 2 Environmental IssuesChapter 22

22-2 Environmental Issues

As the human population increases, so does the human impact on the environment. Humans often cause pollution by putting substances that cause unintended harm into air, water, or soil. Many human activities disrupt ecosystems.




Pollution• Air pollution is blamed for causing:

– Ozone thinning– Global warming– Smog– Acid precipitation



Ozone

• Ozone—A gas molecule made of 3 oxygen atoms.– Harmful in the lower atmosphere– The ozone layer floating 20 km above

earth in the stratosphere. It shields earth from harmful ultraviolet radiation (UV radiation).



Destruction of Ozone Layer• Human-made chemicals such as

chlorofluorocarbons (CFCs) float up to the stratosphere and break down the ozone layer.– CFCs were found in aerosol

sprays and coolants in air conditioners and refrigerators.

– Since 1995 most countries have banned CFCs, but it will take many years for the ozone layer to recover. Destruction of Ozone Layer



Global Warming • May be correlated to

increased amounts of CO2

in atmosphere

• Cutting down rain forests and burning fossil fuels lead to an increase in CO2

in the atmosphere.Global Warming



Smog• Smog is a visible type of air

pollution.– Happens when water vapor

mixes with pollutants from the burning of fuels and use of chemicals in homes and industries.

– May contain nitrogen oxides, sulfur oxides, organic chemicals, small particles, and ozone.

– Animals and plants are harmed by respiring pollutants in smog.



Acid Precipitation• All rain is slightly acidic—CO2 in

the air dissolves in the rainwater, creating carbonic acid.

• Certain air pollutants such as nitrates and sulfur compounds cause an increase in the normal acidity of rainwater.

• Acid rain can destroy forests, damage buildings, and kill fish and other organisms in lakes and ponds.




• Land and Water Pollution– The release of toxic chemicals, such as DDT, into

the biosphere can impact ecosystems in many ways, especially when chemicals undergo biological magnification.

– Biological magnification is a process in which chemicals become more concentrated in organisms that are higher on a food chain.



Chapter 22

Biological Magnification of DDT

Section 2 Environmental Issues



Chapter 22

Bald Eagles Return to the Channel Islands in California

Visual Concept

Biological Magnification of Toxins

Section 2 Environmental Issues



22-3 Conservation and Restoration Biology

• Our planet’s air, water, land and organisms are interconnected. Environmental problems connect across national boundaries, so solutions may require world wide efforts.



Section 3 Environmental SolutionsChapter 22

• Conservation biologists are concerned with identifying and maintaining ecosystems, while restoration biologists are usually involved with repairing badly damaged ecosystems.

• Environmental problems can be addressed through the combined efforts of governments, scientists, businesses, and individuals.



Section 3 Environmental SolutionsChapter 22

Your Role in the Environment

• No one can predict our environment’s future, but it is clear that individuals can make a difference in its fate.

• Thus, it is important for you, as an individual, to understand your role in the environment and to take responsibility for that role.



Chapter 22

Click below to watch the Visual Concept.

Visual Concept

Conservation

Section 3 Environmental Solutions

copyright © by holt, rinehart and winston. all rights reserved. resourceschapter menu section 1 an...

Documents

resourceschapter menu

resourceschapter menu

environmental issues

biodiversity biodiversity

global warming slide

pollution air pollution

environmental science

interconnected planet