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Impact of Extinction on Biodiversity

Explore the consequences of extinction on Earth's biological diversity, including historical losses like the Aurochs, Dodo Bird, and more recent endangered species. Learn about causes like habitat loss, fragmentation, degradation, and the threat of introduced species.

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Impact of Extinction on Biodiversity

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  1. IX. Biological diversity; the variety of species in a specific area. A. Loss of biodiversity; 1. Extinction; the disappearance of a species when the last of its members dies. a. mass extinction; several mass extinctions have occurred throughout Earth’s history. b. background extinction; level of natural extinction that occurs. Scientists estimate the loss at one species per year per million species.

  2. The current rate of extinction exceeds this by many times. Scientist list these factors as the probable cause of the high extinction rate; * expanding human population * loss of habitat * land exploitation

  3. The Aurochs; European member of the cattle family, it was a long-horned, forest-dwelling ancestor of modern domestic cattle. It was hunted for sport and food, and suffered from habitat loss. Its last holdout was in a private game reserve in Poland, but poachers killed it off. The last one died in 1627.

  4. Dodo Bird; Isle of Mauritius (first explored in 1505) Last bird died in 1681. Adults were a little over 3 feet tall. They did not have natural predators until Europeans brought domestic dogs, cats and pigs to the Island. They were often killed for food onboard ships.

  5. Steller’s Sea Cow: This was a heavy, slow-swimming marine mammal (25-30 feet long). It was discovered in 1741 in the Bering Sea (far north Pacific Ocean). It was used as food by sea-otter hunters, and was extinct by 1768, 27 years after its discovery.

  6. Great Auk; The last pair, found incubating an egg, were killed on 3 July 1844, on the island of Eldey off Iceland

  7. Quagga; From South Africa, related to wild horses. Last one killed in the wild in 1878. Last one in captivity dies in an Amsterdam zoo on August 12, 1883.

  8. Passenger Pigeon; The last known individual of the passenger pigeon species was "Martha" (named after Martha Washington). She died at the Cincinnati Zoological Garden, on Sept. 1, 1914.

  9. Carolina Parakeet: This is the only parrot native to North America The last known wild specimen was killed in Florida, in 1904, and the last captive bird died at the Cincinnati Zoo on February 21, 1918.

  10. 1936 World's last captive thylacine (Tasmanian Wolf) died in Hobart Zoo, ( 7/9/36).

  11. Pyrenean Ibex- last one died in 2000

  12. Ivory Billed Woodpecker Last confirmed sighting ? Depends on who you talk to,, 1936, 1944,,,2006!

  13. 2. Endangered species; numbers have become so low that extinction is possible. • American Bison: by 1903, about 2000 animals. • Bison are not endangered anymore. b. Whooping Cranes: in 1941 estimates of 16 wild birds. They are still on the endangered list. 3. Threatened species; likely to become endangered. a. Bald eagle was endangered, but has now been put on the threatened species list.

  14. B. Threats to biodiversity; 1. habitat loss 2. habitat fragmentation; wilderness areas are separated from one another. This is usually because of roads, towns or fencing. 3. habitat degradation; loss of habitat due to pollution.

  15. a. air pollution; ex. acid rain b. water pollution; ex. heavy metals such as mercury c. land pollution; ex land fills, herbicides and pesticides (DDT) 4. Exotic or Introduced species; introduced intentionally, or accidentally. They displace the native species. They usually are not immediately affected by local predators or competitors.

  16. Kudzu; From Asia and the Pacific Islands- introduced in about 1930 to control erosion. Abandoned textile plant in North Carolina

  17. Salt cedar (tamarisk); from the Mediterranean area. Used in the 1930’s for erosion control.

  18. Zebra mussels first seen in the US in 1988. They originated around the Black and Caspian Seas.

  19. Jumping Asian carp (silver carp)- Introduced in the early 1990’s. They destroy aquatic plants that are the source of food for native species.

  20. Snake head fish from Asia; It is invading waters in the North Eastern, and Western US. Introduced in 1997. They are a major predator, killing native fishes. The can move across land to travel from one lake to another.

  21. Fire ants first entered the US through a port in Mobile, Alabama in the 1930’s

  22. Burmese pythons have been recognized as having breeding populations in the Florida Everglades since 2000.

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