u 5 lesson 3 integrado e.s. environmental changes
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Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
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Change Comes Naturally
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• All environments change over time. Some changes happen slowly and some occur quickly.
• Climate changes, or changes to weather patterns, affect organisms.
• An ice age happens when Earth’s temperatures are colder than normal for a very long time. Large areas of land are covered in ice for thousands of years.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Change Comes Naturally
Copyright © Houghton Mifflin Harcourt Publishing Company
• What kinds of changes to the environment may have happened during the last ice age?
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Change Comes Naturally
Copyright © Houghton Mifflin Harcourt Publishing Company
• Earth is now in a warming cycle, due in part to human activities. As areas become warmer, organisms will move, adapt, or disappear.
• Natural events, such as floods, mudslides, or volcanic eruptions can change the environment quickly.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Next, Please!
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• The gradual change of organisms in an ecosystem is called succession.
• Primary succession begins on bare rock. The first organisms to colonize are called pioneer species.
• Lichens, common pioneers, break down rock as they grow, producing soil. When they die, their litter decays, adding nutrients to the soil.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Next, Please!
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• Plants grow as soil develops. Mosses flourish, producing more soil. Bigger plants take hold and, eventually, trees grow.
• This establishes a mature, stable community. This process can take hundreds of years.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Next, Please!
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• Secondary succession occurs where an ecosystem has been disturbed, but soil is still present.
• Secondary succession occurs more quickly and uses existing soil that contains seeds and roots that sprout and grow.
• Shrubs and grasses grow first, followed by larger plants. Eventually, a stable ecological community is re-established.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
For Better or Worse
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• Organisms living in an environment can cause both harmful and helpful changes.
• For example, beavers cut down trees that provide food and shelter for other living things in order to make a dam.
• The dam also slows the flow of water to animals. However, dams also produce wetlands, providing homes for other organisms.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Invasive Species
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• Invasive species grow quickly after being introduced into a new environment.
• Invasive species take food and space away from native species, the organisms already living in an ecosystem.
• Invasive and native species compete for food.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
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• Human activities such as open-pit mining, cutting down forests, and building highways can harm an ecosystem.
• Humans produce waste, which ends up in landfills. These landfills can pollute soil and water.
• Pollution is the contamination of air, water, or soil by substances harmful to organisms.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Humans Change the Environment
Humans Change the Environment
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• Not all changes caused by humans are harmful.
• Conservation is the act of protecting ecosystems and the organisms living in them.
• Humans practice conservation by replanting trees, cleaning up pollution, removing invasive plants and animals, and caring for injured animals.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Gone!
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• Some organisms do not survive changes in the environment.
• Extinction happens when all the members of a certain species dies.
• For example, giant reptiles like the Tyrannosaurus rex lived in a time when the Earth was warm. As the environment cooled, they became extinct.
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
Gone!
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• Could the extinction of the dodo bird have been prevented? Why or why not?
Unit 5 Lesson 3 How Do Environmental Changes Affect Organisms?
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