Presentation on theme: "Endangered Species “Some say we’re on the verge of the sixth mass extinction- wrong! we are in the middle of it- entirely human-made.” Britney Culm SBI4U."— Presentation transcript:
Endangered Species “Some say we’re on the verge of the sixth mass extinction- wrong! we are in the middle of it- entirely human-made.” Britney Culm SBI4U December 17 th 2009
Habitat Loss Most important cause of extinction Tropical rain forest harbours millions of species found nowhere else Many are restricted to a single area, so clearing a single area can eliminate hundreds of species forever ¼ to 1/3 of original tropical forests are gone Estimated 200 000sq/km are converted for human use every year http://static.guim.co.uk/sys-images/Environment/Pix/pictures/2008/05/14/brazil- stephenferry-getty460.jpg
Habitat Loss Cont. Considered most likely cause of mass extinction Drop in sea level destroys broad regions of shallow water habitats Rivers erode down to new levels, altering land habitats Great loads of sediment dumped into once clear waters http://web.vims.edu/bio/sh allowwater/images/shallo w-water-cross600.gif
Habitat Loss Cont. Crested Ibis - National treasure of Japan and Korea Florida Panther - medium-sized sub- species of the cougar or mountain-lion Northern hairy-nosed wombat – marsupial with backwards facing pouch Pinta Galapagos Turtle – “Lonesome George” http://news.bbc.co.uk/nol/shared/spl/hi/pop_ups/07/sci_nat_enl_1177 952310/img/1.jpg
Habitat Loss Cont. Asian elephants are becoming endangered They used to run free, but they are rounded up and used for work in Thailand Forest once covered 90% of Thailand, now it only covers 20% Elephants are forced to tear down forests that are their own habitat http://imagecache2.allposters.com/images/RHPOD/557-2844.jpg
Habitat Loss Cont. Grizzly Bears require hundreds of square kilometers of land Clear-cut logging is the worst for the Grizzly, they will not cross large open areas Roads have serious negative impact on the bears Females need quality habitats for food, crucial for babies http://www.alaska-bear- viewing.net/image_support/images/standing_be ar2_small.jpg
Overkill Humans have lived as hunter-gatherers, wiping out many large marsupials Large animals greatly affected while smaller animals were barely affected Skeletal remains show that large prey were run off cliffs by humans The prey were slow- breeding animals and became quickly extinct http://www.joevenusartist.com/Images/Saber-Tooth-Cat.jpg
Overkill Cont. If resources are used faster than they are produced, the result is predictable Greater number of species extinct in past 200 years than what became extinct in more than 2000 before industrial revolution Human population likely to increase too 10 billion by 2050
Overkill Cont. If present trends continue, mass extinction will be definite Overkill was found to be the main cause in virtually all modern extinctions of large mammals Sometimes overkill is from mistaken belief that wild species were a threat to gardens or domestic animals Predators introduced by humans, wiping out many species, where there were previously no predators http://www.hospitalplay.com/_MEDIA/images/site/soundsDomAnimal.jpg
Pollution Chemical industries cause grave problems for many species DDT and other pesticides find their way into the environment Pollutants are passed from animal to animal and is eventually concentrated in the bodies of top predators Carbon dioxide, methane and nitrous oxide increase insulating power of atmosphere making planet warm up 1.1°C in past 150 years Seals and sea lions affected by growing problem of marine pollution: oil spills, human sewage, disel fuel from ships, floating bits of plastic http://www.learner.org/courses/envsci/visual/img_lrg/ddt.jpg
Interesting Facts “Humans are relatively large animals. When we look at a landscape we are aware of the mammals, birds and reptiles- relatively large, back-boned species like ourselves. We give little thought to the countless billions of smaller creatures such as insects, worms and microorganisms that actually contribute far more to the survival and health of global ecosystems” McGavin, G. C. (2006). Endangered: Wildlife on the Brink of Extinction. Great Britian: Cassell Illustrated.
Interesting Facts Cont. “Extinction” may be a negative word to many, but it is a natural process When dinosaurs became extinct, mammals evolved and diversified in their place Having a broader range increases the species’ chance for survival, but no guarantee The larger a species and the longer ago it lived, the more likely it is to be truly extinct Over time every species is fated for extinction, increase in groups extinct over short periods of time Mass extinctions happening more frequent, more sudden and more important in shaping course of life’s evolution http://www.debraaustinbooks.com/images/evolution.jpg
Interesting Facts Cont. Geologists examine fossil records, it appears a species is extinct- but it has simply evolved to a point where descendants are recognized as a different species, known as pseudoextinction Claimed dinohippus is pseudoextinct- evolved into horses, zebras and wild donkeys Bipedal dinosaurs, increasingly likely they evolved into modern-day birds Species need natural predators to hunt them, otherwise they will overpopulate, decrease in resources, more competition and they will eventually die out http://www.amnh.org/exhibitions/horse/images/lg/02b_ evo_dinohippus.jpg
Conclusion The diversity of the animals on this planet is diminishing at an alarming rate. We need to change our ways, and we need to change them fast. Many species have become extinct, are endangered and will become extinct, and what is it all because of? One species – humans.
Works Cited Bellos, A. (2000, January 27). The World’s Rarest Species. The Globe and Mail, p.R9. Bennell, B. (1998, December 15). The Bear Facts. The Globe and Mail. Extinct and Endangered Species. (2001). In Encyclopedia Americana (Vol. 10, pp. 798- 803). Grolier Incorporated. McGavin, G. C. (2006). Endangered: Wildlife on the Brink of Extinction. Great Britian: Cassell Illustrated. Mecir, A. (2000, May). Sad Plight of the Asian Elephant. Reader's Digest, 70-77. Repanshek, Kurt. (2009, Oct). Leap Frog. Science Reference Centre, 111(5). Retrieved from EBSCOhost database. Species at Risk: The Endangered North Atlantic Right Whale (nd). Government of Canada. Ventor, O., Belland, B., Namiroff, L., Broleur, N., Dolinsek, I., and Grant, J. (nd.). Threats to Endangered Species in Canada. Bioscience, 56(11), 903-910. Retrieved from