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Environmental Biology Presentation Wildlife Extinction Robert I. Walls Spring 2012 Professor Donald Keith.

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Presentation on theme: "Environmental Biology Presentation Wildlife Extinction Robert I. Walls Spring 2012 Professor Donald Keith."— Presentation transcript:

1 Environmental Biology Presentation Wildlife Extinction Robert I. Walls Spring 2012 Professor Donald Keith

2 History

3 The Irish Elk First documented extinction –Discovered by Thomas Molyneux, 1697 –Extinction described by Georges Cuvier, 1812 Museum of Natural History, Washington D.C.

4 The Five Extinction Events Ordovician–Silurian Late Devonian Permian–Triassic Triassic–Jurassic Cretaceous–Tertiary Palais de la Découverte, Paris, photo by David Monniaux.

5

6 The Sixth Extinction Event

7 The Two Phases Human dispersal ~100,000 B.P. Agriculture discovered ~10,000 B.P.

8 The Most Susceptible K-selected Specific survival requirements Small population size Close to humans No conservation programs

9 Major Causes Overexploitation Pollution Invasive exotics Habitat Degradation

10 Overexploitation

11 Dodo Birds Island of Mauritius Used as food by Portuguese sailors Exotic species introduced Extinct by 1681 Tree found to depend on Dodo digestion of seeds for germination

12 Saddle-backed Rodrigues Giant Tortoise Island of Rodrigues, Republic of Mauritius Hunting pressure Last reported: 1795

13 In 1761, Abbé Pingré wrote: "The tortoise is not a pretty animal, but it was the most useful of those we found at Rodrigues. In the three and a half months that I spent on the island, we ate almost nothing else: tortoise soup, fried tortoise, stewed tortoise, tortoise forcemeat, tortoise eggs, tortoise liver - these were pretty much our only savouries. This meat seemed to me as good on the last day as on the first; I did not eat many of the eggs; the liver seemed to me the most delicious part of the animal. After five weeks stay I was attacked by dysentery which I kept secret, because I counted more on myself to heal it than the island's surgeon. Diet and rest put me right in a few days, but it left me with an extraordinary involuntary repugnance for this liver that I had so liked until then. Should I thus regard it as the cause of my indisposition?...Tortoise fat is very abundant and does not congeal; it is what is known as tortoise oil. This oil had no bad taste, it is very healthy, and we seasoned our salads with it, used it in frying and all our sauces. Rodrigues tortoises are a foot and a half long and bout a foot across; they were formerly large, but they are no longer given time to grow. When a bigger one is found, it is called a carrosse. These carrosses cannot harm a waken man, though they have sometimes bitten sleepers hard. The shells of these tortoises served us like baskets to carry oysters and similar provisions. The flesh of these tortoises is the colour of mutton, and approaches it for taste" (Pingré, 1763; Cheke and Hume, 2008).

14 Quagga South Africa Aggressively Hunted Used for meat Skin used for grain bags and leather The only living quagga ever photographed - at the London Zoo in 1870, 13 years before the subspecies went extinct

15 Sperm Whale Harvest Records for the United States Year# ShipsEst. WhalesEst. Oil Barrels ,598172, ,943157, ,494157, ,08892, ,19772, ,24373, ,46333, ,42855, ,65637, ,06524,203 Data from Gosho et al. 1984

16 Pollution

17 Bird Sanctuary DDT effects on birds first studied by Rachel Carson (late 50’s to early 60’s) Deaths of robins, catbirds, doves, jays, wrens, and other birds linked to pesticide exposure

18 Invasive Exotics

19 The Tasmanian “Wolf” Canine-like marsupial Competed with introduced dingo Bounty placed by Europeans

20 Habitat Degradation

21 Three Tiger Subspecies Bali Javan Caspian

22 Guam Flying Fox Guam, Marianas Islands, Micronesia Last record: 1974 Habitat degradation and hunting believed to be causes of extinction

23 Gastric Brooding Frog Eastern Australia Offspring incubated in stomach Last seen in 1985

24 IUCN Red List of threatened species 10,002 vulnerable 5,689 endangered 3,879 critically endangered 64 extinct in wild 801 extinct

25 Literature Cited Carson, R Silent Spring. Houghton Mifflin. Boston, MA. Gould, S. J The Origin and Function of 'Bizarre' Structures: Antler Size and Skull Size in the 'Irish Elk,' Megaloceros giganteus. Evolution 28(2): Lowenstein, J. M. and O. A. Ryder Immunological systematics of the extinct Quagga (Equidae). Experimentia 41: Vernon, J. E. N Mass extinctions and ocean acidification: biological constraints on geological dilemmas. Coral Reefs 27(3): Gosho, M. E., D. W. Rice, and J. M. Breiwick The sperm whale, Physeter macrocephalus. Marine Fisheries Review 46(4): Bringing Back the Quagga Accessed 02/23/2012. Cylindraspis vosmaeri htm. Accessed 03/16/2012. Gastric Brooding Frog profiles/amphibians/Pages/Rheobatrachus_vitellinus-silus.aspx. Accessed 03/17/2012. Guam Flying Fox - Pteropus tokudae guamflyingfox.htm. Accessed 03/16/2012. The Dodo Bird Extinct. Accessed 03/20/2012.


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