Endangered species.pdf - Endangered species Endangered species are living things threatened with extinction \u2014that is the dying off of all of their

Endangered species.pdf - Endangered species Endangered...

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Endangered species Endangered species are living things threatened with extinction —that is, the dying off of all of their kind. Thousands of species of animals and plants are endangered, and the number increases each year. Some examples of endangered species are blue whales, giant pandas, orangutans, rhinoceroses, sea turtles, snow leopards, tigers, and whooping cranes. Among endangered plants are running buffalo clover, Santa Cruz cypress, snakeroot, and many species of cactuses. Each species of plant and animal plays a part in the delicate balance of its ecosystem, its relation to other living things and the environment. Thus, the extinction of large numbers of species threatens the survival of other living things, including human beings. As more species have become endangered, ecosystems have become unstable or collapsed. Fortunately, people have increased their efforts to protect endangered species. See Wildlife conservation (Values of wildlife conservation) . Most biologists consider a species endangered if they expect it would die off completely in less than 20 years if no special efforts were made to protect it, or if the rate of decline far exceeds the rate of increase. Until the last few centuries, species became rare or died out as a result of natural causes. These causes included changes in climate, catastrophic movements in Earth's crust, and volcanic eruptions. Today, species become endangered primarily because of human activities. Species mainly become endangered because of (1) loss of habitat, (2) wildlife trade, (3) overhunting, and (4) competition with domestic and nonnative animals. © 2016 World Book, Inc. All rights reserved. WORLD BOOK and the GLOBE DEVICE are registered trademarks of World Book, Inc.
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