Transcript Endangered: Wildlife on the Brink of Extinction.

Endangered Species
“Some say we’re on the verge of the sixth mass extinctionwrong! we are in the middle of it- entirely human-made.”
Britney Culm
SBI4U
December 17th 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/brazilstephenferry-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 subspecies 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-bearviewing.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 slowbreeding 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
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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.
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“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. 798803). 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 <http://web.ebscohost.com/ehost>