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Chapter 5: Biomes and Biodiversity

Principles of EnvironmentalScience - Inquiry and Applications,

3rd Editionby William and Mary Ann Cunningham

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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Part 1: Biomes

Biomes

• Broadly defined life zones

• Environments with similar climates, topographies, soil conditions, and biological communities

• Distribution mainly dependent on temperature and precipitation

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ADD FIG. 5.1

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Biomes of the World

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ADD FIG. 5.4

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Part 2: Biodiversity

• Genetic diversity - variety of different versions of the same genes within a species

• Species diversity - number of different kinds of organisms within an ecosystem

• Ecological diversity - complexity of a biological community (number of niches, trophic levels, etc.)

Biodiversity - the variety of living things - three types essential:

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How many species are there?

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Biodiversity Hotspots

Most of the world's biodiversity concentrations are near the equator (tropical rainforests, coral reefs).

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Part 3: How do we benefit from biodiversity?

• Food

• Drugs and medicines

• Ecological benefits

• Aesthetic and cultural benefits

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Fig. 5.21

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Aesthetic and culturalbenefits

Bird watching and other wildlife observationcontribute more than $29 billion each year to the U.S. economy.

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Part 4: What Threatens Biodiversity?

Extinction - the elimination of a species

• Natural process - one species lost every 10 years

• Process been accelerated by human impacts on populations and ecosystems

• E.O. Wilson - we are currently losing thousands of species a year

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Part 5: Human-Caused Reductions in Biodiversity

• Habitat destruction and fragmentation• Hunting and fishing• Commercial products and live specimens• Predator and pest control• Exotic species introduction• Diseases• Pollution• Genetic assimilation

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About 200 years ago, the American passenger pigeon was probably the world's most abundant bird.

Population: 3-5 billion

Over hunting and habitat destruction caused its extinction.

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Trade in Products from Endangered Species

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Trade in Wildlife

About 75% of all saltwater tropical aquarium fish sold come from coral reefs of the Philippines and Indonesia, where they are commonly caught with dynamite or cyanide.

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Part 6: Protecting Biodiversity

• Hunting and fishing laws• The Endangered Species Act (ESA)• Recovery plans• Reintroductions• Minimum viable population• Private land and critical habitat• Reauthorization of the ESA• International wildlife treaties

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