Evolution title
portion of frog image
More on Endangered Species

More on endangered species | Fossil collecting | Educational standards | Other regions

an endangered Florida panther The Endangered Species Act
While extinction is a natural occurrence in evolution, the sharp decline of wildlife and flora -- largely attributed to human activity -- has stirred legislative action in the United States. Acknowledging that a rich natural heritage was of "esthetic, ecological, educational, recreational, and scientific value to our Nation and its people," the federal government passed the Endangered Species Act (ESA) in 1973 to protect species in danger of extinction and to conserve the ecosystems in which they live.

As of January 31, 2001, the federal register includes 972 endangered species, which the ESA defines as any species "in danger of extinction throughout all or a significant portion of its range." Of the 972, 379 are animals and 593 are plants. Another 128 animals and 144 plants are listed as "threatened" species, or in peril of becoming endangered. Most of the endangered species (565) are flowering plants. Birds (78), fishes (70), mammals (63), and clams/mussels (61) follow in order.

The U.S. Fish and Wildlife Service and National Marine Fisheries Service are responsible for administering the law, which they do in conjunction with other federal agencies and state governments.


Read more: (see below)
Extinction by the numbers
Biodiversity matters
Making the list
Recovery efforts
State listings
What you can do


Extinction by the numbers
In 1997, the Association for Biodiversity Information published estimates of the number of species that have gone missing or are presumed extinct in each state of the United States since America was colonized by Europeans. The report card says that virtually every U.S. state has lost species through extinction (526 species total), with Hawaii (269), Alabama (98), and California (46) incurring the most losses. Birds, freshwater mussels, freshwater fishes, and flowering plants lead the list of species known to be extinct.


Biodiversity matters
The U.S. Fish and Wildlife Service lists the following as reasons for protecting endangered species:
  • A healthy environment for wildlife contributes to a healthy environment for people
  • Protecting endangered species and biodiversity saves species that may become important sources of new drugs, medicines, or foods
  • Endangered species are Nature's "911," an early-warning system for pollution and environmental degradation that may someday affect human health
  • Endangered species are linked to environmental quality

Making the list
Human activities such as urban development, farming, damming, and pollution are driving the decline in species through destruction of habitats. These activities affect animals and plants in all places -- on land, in oceans and rivers, and in the air. In fact, habitat destruction endangers an estimated 80 percent of the federally listed species. When populations reach critically low levels, they become candidates for endangered status.

Each year since 1980, the list of endangered and threatened species has grown. In 1980, 281 species were listed; today that number is 1,244. About 30 endangered species have been removed from the list. In some cases, like those of the American peregrine falcon and American alligator, it's been cause for celebration. These species maintain large enough populations to have "recovered." For several others, however, the story is not so happy: The blue pike and the Tecopa pupfish are now extinct, gone forever.



Recovery efforts
Recovery plans have been created for many listed species. These strategic plans include conservation measures that identify and address threats in order to reverse the decline. Only 11 species to date have been delisted due to recovery, in large part because it takes a long time (50 to 100 years for many slowly reproducing species) to ensure survival.


State listings
The federal listing includes species whose territories may extend widely across the country. Individual states designate species as endangered, threatened, or otherwise according to their status within state borders. For example, an animal may have healthy populations across several states in its territorial range and thus not be considered endangered by federal standards. But should its numbers be dangerously low in a state it typically inhabits, it would be listed as endangered in that state. More species appear on state registers than on the federal listing.


What you can do
  • Recognize which listed plant and animal species appear in your region
  • Learn about the importance of conserving biodiversity by visiting local aquariums, zoos, and nature centers. These places offer opportunities to get to know the territorial range behaviors exhibited by native and foreign species in the U.S.
  • Support groups that petition for the protection of species and work toward their recovery
  • Protect critical habitats that support populations of threatened or endangered species
  • Adopt an endangered species as a classroom or community project and learn how to help conserve it
  • Create public awareness about environmental issues, such as programs designed to offset waste and pollution
  • Write or call state or local legislators to encourage them to enact conservation-minded policies


Explore Evolution online at www.pbs.org/evolution
Back to your local station's home page