Read e-book online Animals: Creatures That Roam the Planet (Natural Resources) PDF

By Julie Kerr Casper PhD

ISBN-10: 0816063532

ISBN-13: 9780816063536

ISBN-10: 143810555X

ISBN-13: 9781438105550

In the course of the process thousands of years, animals have tailored to numerous environments in the world. even supposing animals have developed over geologic time to Earth's consistently altering environments, and even though the extinctions of convinced species are common, in no different time within the planet's historical past has the extinction fee climbed as excessive because it is this day. factors of this unparalleled extinction expense contain destruction of natural world habitat, pollutants, overfishing, and poaching. "Animals" illustrates those pressing matters in a fashion available to center and highschool readers.

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Additional resources for Animals: Creatures That Roam the Planet (Natural Resources)

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300 million Earthworms appear. 350 million Ferns appear. 360 million ­ Four-­limbed vertebrates exist, and seed plants and large forests appear. 400 million Sharks appear. 420 million L and plants evolve, drastically changing Earth’s landscape, and new habitats are created. 450 million  rthropods live on land. Their descendants evolve into scorpions, spiders, A mites, and millipedes. 500 million Vertebrates evolve. Invertebrates are common in the oceans. 555 million Multicellular marine organisms are common.

When sea levels lower, land that had previously been covered by water can become exposed as the ocean level declines. When these land bridges are present, species can walk across them to other locations. For example, scientists believe that the Bering Land Bridge that existed between Alaska and Russia when the sea level was lower was used by many species—such as Siberian huskies and even humans—to migrate from Russia to North America. After the sea level rose, the land bridge disappeared beneath the ocean.

Many governments have made hunting and trading various animals illegal and have set up endangered species lists in order to protect animals from extinction. 41 CHAPTER 3 Renewable and Nonrenewable resources T here are two general classes of resources: renewable and nonrenewable. This chapter focuses on how energy flows through an ecosystem, the importance of food webs to animal survival, and the important physical cycles that affect animals and their relationship with the environment. If these critical cycles remain in balance, then the needs of the system are met and resources don’t become endangered.

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Animals: Creatures That Roam the Planet (Natural Resources) by Julie Kerr Casper PhD

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