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Program Big Cats Initiative

Background Info

Human activities threaten the existence of plants and animals worldwide. Overhunting, deforestation, and encroachment on natural habitats all pose threats. The current rate of species extinction is between one hundred and one thousand times greater than the expected natural rate. A 2008 International Union for Conservation of Nature (IUCN) report stated that nearly one third of amphibians, one in eight birds, and one in four mammals are threatened with extinction. Ecosystem functioning depends on the existence and health of numerous interacting species. These interactions make human life possible. Habitat loss, illegal killing, and human encroachment threaten big cat populations. Conservation efforts have helped sustain populations of other endangered species like the humpback whale, whooping crane, and grizzly bear. Scientific research and concentrated breeding programs can help preserve species.



What human activities threaten animal and plant populations worldwide?

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Animal and plant populations are threatened by hunting, deforestation, and human encroachment on natural habitats.


What are two conservation measures used to increase humpback whale populations?

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Two conservation measures used to increase humpback whale populations are banning commercial whaling (1966) and setting speed limits along whale migratory routes.


What are scientists in the Galapagos doing to bring back an extinct species of tortoise?

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Scientists are using selective breeding to isolate and recombine genes of a related species in order to "resurrect" the extinct tortoise.


Can the extinction of species cause an ecosystem to no longer function? Why or why not? What are some examples?

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Answers will vary and should be discussed. The extinction of one species may not seem to have an immediate or direct effect upon an ecosystem, but over time it could. The extinction of one species is also likely to impact the health of other species, and therefore the ecosystem as a whole. Examples include the loss of top predators like wolves, pollinators like bees, and native plants and animals that are specifically adapted to a particular ecosystem.

For Further Exploration


Media Credits

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Angela M. Cowan, Education Specialist and Curriculum Designer


Julie Brown, National Geographic Society

Expert Reviewer

Dr. Luke Dollar, Conservation Scientist


Alison Michel

National Geographic Program

Big Cats Initiative


Vié, J.-C., Hilton-Taylor, C. and Stuart, S.N. (eds.) (2009). Wildlife in a Changing World–An Analysis of the 2008 IUCN Red List of Threatened Species. Gland, Switzerland: IUCN. 180 pp.

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