Download Ch. 5 Sect. 1 Notes ‐ Biodiversity A. Biodiversity—variety of life in an

Ch. 5 Sect. 1 Notes ‐ Biodiversity
A. Biodiversity—variety of life in an ecosystem
1. Biodiversity is measured by the number of species that live in an area.
2. Biodiversity tends to increase in warmer, moister climates such as tropical regions.
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B. Importance of biodiversity
1. People find beauty and pleasure in nature’s biodiversity.
2. Hundreds of species help feed the human population and helps improve food crops
3. Provides people with useful materials
a. Wood to build furniture and buildings; cotton, flax and wool for cloth; plants to make medicines
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4. Allows for stability in an ecosystem
a. Loss of biodiversity can weaken an ecosystem.
b. Biodiversity on a farm helps prevent disease and reduces the need for pesticides.
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C. Reduction of biodiversity
1. Extinct species—a species that was once present on Earth but has died out
a. Extinction can be caused by competition from other species or by changes in the environment.
b. Rate of extinction appears to be rising.
Check out this link to the 10 most amazing extinct animals!
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2. Endangered species—a species in danger of becoming extinct
3. Threatened species—a species likely to become endangered in the near future
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4. Habitat loss—a major reason why species become threatened or endangered
a. When people alter an ecosystem, habitats of some species may become smaller or disappear completely.
b. The Lake Erie water snake is classified as threatened because development of some areas has caused habitat loss.
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5. Introduced species—a species that moves into an ecosystem as a result of human actions
a. Often have no competitors or predators in a new area
b. Can crowd out or consume the native species, or original organisms in an ecosystem
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D. Biodiversity is affected by pollution of land, water, or air.
1. Soil contaminated with oil, chemicals, or other pollutants can harm plants.
2. Water‐dwelling organisms are easily harmed by pesticides, chemicals, and other pollutants.
Waste being dumped directly into this river leads to.... (see next slide)
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Many dead fish in the river (as a result of the pollution in the water)
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Let's see what you know by taking a Self Check Quiz!
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