Humsns And The Environment

transcript

Humans and the Environment

Table of Contents

Section 1 An Interconnected Planet

Section 2 Environmental Issues

Section 3 Environmental Solutions

Objectives

• Explain the importance of the study of environmental science.

• Describe Earth’s major layers.

• Explain the natural functions of the ozone layer and greenhouse effect.

• Summarize the ways in which biologists measure biodiversity.

• Discuss the value of biodiversity.

Earth’s Layers

• Earth’s geosphere, hydrosphere, and atmosphere are interconnected in many ways.

• Together, these parts make up the biosphere, the part of the Earth where life exists.

Earth’s Layers, continued

• Atmosphere– Important parts of the atmosphere are greenhouse

gases, which trap heat on Earth, and the ozone layer, which shields Earth from UV radiation.

• Climate and Atmosphere– The atmosphere’s ability to trap heat in this way is

called the greenhouse effect.

The Greenhouse Effect

• Hydrosphere– A very small portion of the hydrosphere is fresh

water, and much of this fresh water is not easily usable.

• Geosphere– The geosphere exchanges materials with the

atmosphere, hydrosphere, and biosphere.

• Biosphere– The biosphere includes all parts of Earth where

life exists.

Biodiversity

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

Biodiversity, continued

• Measuring Biodiversity– Biodiversity can be measured in different ways,

including by species richness, species evenness, and genetic diversity.

Biodiversity, continued

• Valuing Biodiversity– Biodiversity is valued for various reasons.

Objectives• Describe major consequences of air pollution.

• Relate air pollution to effects on global climate.

• Describe how chemical pollutants may undergo the process of biological magnification.

• Identify the primary causes of modern extinctions.

• Explain why extinctions and ecosystem disruption are of concern to humans.

• Relate human resource use to its impacts on ecosystems.

Pollution

• Over a short time period, human activities have affected global ecosystems in ways that harm humans and other species.

• Human impacts range from local pollution to global change in ecosystems.

Pollution, continued

• Ozone Thinning– Industrial chemicals called chlorofluorocarbons

(CFCs) act as catalysts in chemical reactions that break down O3 molecules in the ozone layer.

– Most countries have banned CFCs, and the ozone layer seems to be recovering.

Ozone “Hole” Over Antarctica

Click below to watch the Visual Concept.

Visual Concept

Ozone and Ecosystems

• Global Warming

– The correlation of increasing atmospheric CO2 and rising global temperature suggests a cause-and-effect relationship.

– Considering several types of evidence, many scientists have concluded that increased CO2 levels have caused warmer surface temperatures on Earth.

Visual Concept

Global Warming

• Acid Precipitation– Certain air pollutants cause acid precipitation,

which harms or kills many organisms.

• 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 of DDT

Visual Concept

Biological Magnification of Toxins

Ecosystem Disruption, continued

• Extinction– Human impacts on the environment are causing

an increasing number of extinctions. – Important causes of extinctions are habitat

destruction, the transfer of invasive species to new habitats, harvesting, and hunting.

– This loss of species has both known and unknown effects on ecosystems.

Ecosystem Disruption, continued

• Ecosystem Imbalances– Species such as the sea otter that affect many

other species in a community are called keystone species.

Human Resource Use

• Current levels of human resource use are probably not sustainable.

World Population Growth Patterns

Objectives

• State the goals of conservation and restoration biology.

• Describe examples of efforts to protect species and their habitats.

• Summarize international strategies for protecting entire ecosystems.

• Discuss the roles of governments and laws in addressing environmental problems.

• List several things that individuals can do to help solve environmental problems.

Conservation and Restoration Biology

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

Conservation and Restoration Biology, continued

• Species and Habitats– A bioindicator is a species that is especially

sensitive to ecological change.

Conservation and Restoration Biology, continued

• Case Study: Saving the Whooping Crane– Populations of many migratory birds, such as the

whooping crane, are in decline because of human activities.

– However, some populations are recovering as a result of legal protection, breeding programs, habitat restoration, and international partnerships.

Protecting Ecosystems

• Biodiversity Hotspots– International and cooperative efforts to preserve

habitat and prevent extinctions include identifying biodiversity hotspots, making debt-for-nature swaps, and promoting ecotourism.

Governments and Laws

• Environmental problems can be addressed through the efforts of governments and laws.

Private Efforts and Cooperation

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

Conservation Case Study: The Everglades

• The Everglades restoration project is the most ambitious ecosystem-wide restoration project attempted in the United States.

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.

Visual Concept

Conservation

Humsns And The Environment

Education