Download Chapter 22 Humans and the Environment 22-1 An

Chapter 22
Humans and the Environment
22-1 An Interconnected Planet
Environmental Science- the study of the interaction between humans and their
environments.
Earth’s Layers
Atmosphere- the mixture of gases that surround Earth.
-78% N, 21% O2, 1% H2O, H2O vapor, CO2, ….
-gases become less dense at higher altitudes
-Ozone, O3, -in the ozone layer – about 20 km above the Earth’s surface.
-absorbs about 99% of the UV radiation.
-Greenhouse effect- P. 436. The ability of gases in the atmosphere to trap heat. Gases such
as CO2 and methane are greenhouse gases.
Hydrosphere-the parts of the Earth that contain H2O
-oceans cover about 70% of Earth.
-only about 3% of surface H2O is fresh water.
Geosphere- Earth’s rock interior, from core to crust.
-exchanges material with the hydrosphere, atmosphere and biosphere. Ex. C, S, P….
Biosphere- all parts of the Earth where life exists. Includes parts of the geosphere,
hydrosphere and atmosphere.
Biodiversity
-the variety of organisms (forms of life) in an area.
-A way to measure biodiversity is Species Biodiversity- the species richness (# of species)
and species evenness (relative # of individuals of each species) in an area.
-Another way to measure biodiversity is genetic diversity- the amount of genetic variation
within a population.
Biologists estimate there are between 2 million and 100 million species on Earth. About 2
million have been named. New species are constantly being discovered and named. We
have less knowledge about the smallest organisms and those in extreme environments.
The Value of Biodiversity
Utilitarian Value-thousands of species are used as food
-many species are sources of medicines and beneficial chemicals
-many species clean the air, water, and soil and recycle nutrients.
Nonutilitarian Value
-many people feel organisms have value simply because they exist. The idea that the world
is a better place because these organisms are part of the world.
“Biological diversity is the key to the maintenance of the world as we know it”
Edward O. Wilson
22-2 Environmental Issues
Pollution
Smog- (smoke + fog) water vapor mixed with chemicals from human activity–nitrogen
oxide, sulfur oxides, small particulates, and ozone.
Ozone thinning- O3 in the stratosphere shields the Earth. Human made chemicals, such as
chlorofluorocarbons (CFCs) act as a catalyst to break down ozone in the stratosphere.
-1 CFC molecule can break down 100,000 ozone molecules.
-1980’s a thinning of the ozone layer over the Polar Regions was discovered. Could lead to
an increase in skin cancer, cataracts, and damage to photosynthetic organisms.
-most countries stopped producing CFCs by 1995
-it will take 50-100 years for the ozone layer to recover.
Global warming- there is a correlation between levels of CO2 in the atmosphere and
average global temperatures. There is appositive correlation between increased CO2 levels
and global temperatures. P. 441
-Increased global temperatures can alter rainfall patterns, soil moisture, and sea levels
around the world. Temperature changes can change ecosystems.
Acid Precipitation- Some pollutants (such as sulfur from smokestacks and the burning of
coal) combine with water in the atmosphere and form acids, which result in the formation
of acid precipitation.
2S + 3O2 2SO3
SO3 + H2O  H2SO4 (sulfuric acid)
-Acid precipitation changes the pH, causing an increase in the acidity of water and soil,
causing disease or death to trees, fish and other organisms.
Land and Water Pollution
-Human produced pollution from sewage, trash, chemicals, industry, farms, ….can pollute
the water and land.
Biological magnification- P. 442.-Chemicals become more concentrated the higher an
organisms is in the food chain. Ex. DDT and Bald Eagles
Rachel Carson- 1962-She published “Silent Spring”- it warned of the dangers of using toxic
pesticide like DDT.
Ecosystem Disruption
Extinction- we are in a mass extinction caused by human activities.
-loss of habitat is the main cause of extinction today.
Ex. Whooping cranes and migration routes.
Ecosystem Imbalances
Keystone species- removing keystone species from an ecosystem can cause competitive
exclusion, and decrease biodiversity in and area.
Overusing resources
-too much fishing in many areas has depleted the fish populations
-over-farming has caused desertification and the loss of topsoil
Human Resource Use
Ecological footprint- the analysis of human impact on ecosystems- it takes into account use of
food and natural resources, as well as human’s production of wastes and pollution. The
ecological footprint measure may be used to estimate long term sustainability.
Sustainability- the ability to meet human needs in a way that human population can survive
indefinitely.
-develop new technologies for energy, transportation, waste treatment….
-slow human population growth.
-reduce consumption of resources.
22-3 Environmental Solutions
Conservation biology- to save and manage areas that still have high biodiversity. Ex. Preserving
land for a State or National Park.
Restoration biology- restoring areas of extreme ecosystem damage. Ex. The Florida Everglades
Some species are considered bioindicators – a species that is especially sensitive to an ecological
change. They serve as an early warning sign of one or more changes in an environment.
Ex. Dwarf wedge mussels and water pollution, Frogs and water pollution.
Saving an endangered species
-1937- only 15 Whooping cranes remained
-the government regulated hunting and winter refuge sites were established in Texas
-1967- a captive breeding program was started
2001- pilots lead the young cranes in a 2000 mile migration
Other examples from “Don’t Say Goodbye” video.
Biodiversity hotspots- ecological regions that are the richest in unique species and need the
most protection. P. 448.
Debt-for-nature swap- richer countries or private organizations help pay some of the debts of
developing countries. In return, the developing countries preserve natural areas.
Ecotourism- tourism that supports the preservation of ecologically rich areas, and provides a
living for local people.
Cooperation between international governments, conservation groups, and individuals is vital to
solving environmental problems.
Individuals and the media can have a significant impact.
-Henry David Thoreau- “Walden”
-John Muir- First president of the Sierra Club
-Rachel Carson –“Silent Spring”
-Jacques Cousteau- television programs on the ocean
-Jane Goodall- primatologist, conservationist
-Edward O. Wilson- biologist/naturalist, professor at Harvard University
-David Suzuki- environmental activist, TV series “The Nature of Things”
-David Attenborough- television programs on nature
-Steve Irwin- Television programs on nature and conservation
Urban ecology- the study of biodiversity in densely populated areas. P. 452