15.3 key concept biomes are land-based, global communities of organisms

15.3 KEY CONCEPT Biomes are land-based, global communities of organisms.

Earth has six major biomes.

• Rainforest• Grassland (tropical and temperate)• Desert• Temperate Forest (deciduous and rain)• Taiga• Tundra

• There are a variety of ecosystems in each biome.• The biomes are characterized by abiotic factors• The same biomes in different areas of earth have similar plant and

animal species. Ex: tropical rainforest (Brazil and Madagascar)

• Tropical rain forest biomes produce lush forests.– warm temperature– abundant precipitation all year

The tropical rain forest can be found in three major geographical areas around the world. - Central America in the Amazon river basin. - Africa - Zaire basin, with a small area in West Africa; also eastern Madagascar.- Indo-Malaysia - west coast of India, Assam, Southeast Asia, New Guinea and Queensland, Australia.

Source: World Meteorological Organization

– Temperate grasslands are dry and warm during the summer; most precipitation falls as snow.

• Grassland biomes are where the primary plant life is grass.

– Tropical grasslands are warm through the year,

with definite dry and rainy seasons.

Rapid City, South Dakota

• Desert biomes are characterized by a very arid climate.– very low amount of

precipitation– four types: hot, semi-

arid, coastal, and cold

Tucson, Arizona

Source: National Oceanic Atmospheric Administration

– Deciduous trees are the dominant plant species.– The temperate rain forests have a long wet season

and relatively dry summer.

• Temperate forest biomes include deciduous forests and rain forests.– Temperate deciduous forests have hot summers and

cold winters.

– Ferns and moss cover the forest floor. 

• The taiga biome is located in cooler northern climates.– boreal forest– long winters and short

summers– small amount of

precipitationSource: Environment Canada

Banff, Canada

• The tundra biome is found in the far northern latitudes with long winters.– winter lasts 10 months– limited precipitation– permafrost

Barrow, Alaska

Source: National Oceanic Atmospheric Administration

Polar ice caps and mountains are not considered biomes.

• Polar ice caps have no soil, therefore no plant community. • The climate and organisms found on mountains change as

the elevation changes.

Marine Ecosystems

• A. Ocean Zones• 1. Intertidal zone:• Area of beach that you walk on.

• 2. Neritic Zone: • Coral Reefs and Kelp Forests. A few cm – 200• meters deep; intertidal zone out to • continental shelf

• 3. Bathyal Zone:• 200 – 2000 meters; turbid murky water due • to silt; includes mostly burrowing animals.

• 4. Abyssal Zone:• Below 2000 meters, complete darkness, • deep sea vents and chemosynthetic organisms.

Estuaries and Freshwater Ecosystems

• Estuary: A partially enclosed body of water formed where a river flows into an ocean. Ex: San Francisco and Chesapeake Bays, Everglades. Includes harbors, sounds, and inlets. Mixture of freshwater and salt water. High level of nutrients, life thrives here. Lots of biodiversity

Freshwater Ecosystems• River, streams, lakes, ponds, wetlands (bogs, swamps,

marshes): all originate from watersheds.

• Watershed: a region of land that drains into a river, river system, or another body of water.

16.1 KEY CONCEPT As the human population grows, the demand for Earth’s resources increases.

Earth’s human population continues to grow.

• Earth’s human carrying capacity is unknown. J or S?• Technology has helped to increase Earth’s carrying

capacity.

– gas-powered farm equipment

– medical advancements

The growing human population exerts pressure on Earth’s natural resources.

• Nonrenewable resources are used faster than they form.– Coal– Oil– Natural Gas• 77 million barrels per day are used (2006)• Our dependency on these resources is depleting them.

• Renewable resources cannot be used up or can replenish themselves over time.– wind– water– sunlight

Effective management of Earth’s resources will help meet the needs of the future.

• Earth’s resources must be used responsibly. • Careless use of resources makes them unavailable to

future generations.• Easter Island is

an example ofirresponsibleresource use.

• An ecological footprint is the amount of land needed to support a person.

• The land must produce and maintain enough– food and water– shelter– energy– Waste• Several factors affect the size of the ecological footprint.

– amount and efficiency of resource use – amount and toxicity of waste produced

• Ecological Footprint 9.7 hectares = 24 football fields• Hectare = 10,000 square meters

16.2 KEY CONCEPT Fossil fuel emissions affect the biosphere.

Pollutants accumulate in the air.

• Pollution is any undesirable factor added to the air, water, or soil.

• Smog is one type of air pollution.– sunlight interacts with

pollutants in the air– pollutants produced by fossil

fuel emissions– made of particulates and

ground-level ozone– Smog can be harmful to

human health.

• Acid rain is caused by fossil fuel emissions.– produced when pollutants in the water cycle cause rain

pH to drop– can lower the pH of a lake or stream– can harm trees

Air pollution is changing Earth’s biosphere.

• The levels of atmospheric carbon dioxide rise and fall over time.

• High levels of carbon dioxide are typical of Earth’s warmer periods.

• The greenhouse effect slows the release of energy from Earth’s atmosphere.– sunlight penetrates Earth’s atmosphere– energy is absorbed and reradiated as heat– greenhouse gases absorb longer wavelengths– Greenhouse

gas moleculesrereleaseinfraredradiation

methane (CH4) water (H2O)

carbon dioxide(CO2)

• Global warming refers to the trend of increasing global temperatures.

North Pole

16.4 KEY CONCEPT The impact of a growing human population threatens biodiversity.

Preserving biodiversity is important to the future of the biosphere.

• The loss of biodiversity has long-term effects.– loss of medical and technological advances– extinction of species– loss of ecosystem stability

Loss of habitat eliminates species.

• Habitat fragmentation prevents an organism from accessing its entire home range.– occurs when a barrier forms within the habitat– often caused by human development– Habitat corridors are a solution to the problem.– allow species to move between different areas of

habitat

Introduced species can disrupt stable relationships in an ecosystem.

• An introduced species is one that is brought to an ecosystem by humans.– accidental– purposeful

• Invasive speciescan have anenvironmentaland economicimpact.

• Invasive species often

push out native species.

16.5 KEY CONCEPT Conservation methods can help protect and restore ecosystems.

Sustainable development manages resources for present and future generations.

• Sustainable development meets needs without hurting future generations.– resources meet current needs– resources will still be available for future use

Conservation practices focus on a few species but benefit entire ecosystems.

• The Environmental Protection Agency (EPA) was created in 1970.

• The EPA develops policies and regulations to protect the environment.

• Legislation helps to protect the environment and endangered species.– Clean Air Act– Clean Water Act– Endangered Species Act• The National Park Service helps

manage public lands.

• There are several ways that people can help protect the environment.– control population growth– develop sustainable technology and practices– protect and maintain ecosystems