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The previously mentioned maps and data demonstrated
that wildlife adapt to specific areas and that
many species are only found in certain habitats. Many habitats are being destroyed. Barely 1% of the original tall-grass prairie
remains in the
Between 1960 and 1990, 20% of all the earth’s
rainforests were cut. During this
Islands frequently carry species that occur
nowhere else in the world. For
example, of the 135 birds that occurred only in
About 140,000 square kilometers of tropical rainforest are cut/year. During the 1990s, the earth’s forest cover decreased by 4% and about half of the world’s forests have been lost since the dawn of agriculture. More than half the earth’s wild wetlands have been lost during the past century.
Due to population growth alone, the percentage of species in an average nation is expected to rise to about 7% by the year 2020 and 14% by 2050. Human population growth is a primary factor in an estimated 88% of the species whose condition is considered threatened (McKee, 2003).
Extinction is a natural process; it is estimated that over 99.9% of all the living things that have ever existed in earth's history are now extinct. Sometimes extinction occurs at a slow rate; there are other times known as mass extinctions.
Due to the human impact on the natural world, it is estimated that at least 100 species become extinct every day; at this rate, the mass extinction through which we are now living will soon (by the year 2000?) surpass the Cretaceous extinction and become the 2nd largest in earth's history.
Why aren’t you aware of the species which become extinct every day?
1) They are Rare:
at the list of endangered species in
2) Most people are unfamiliar with many groups of organisms, such as insects, freshwater mollusks, etc. Ninety-five percent of all animal species are invertebrates and therefore many species could go extinct from your area without your being aware of them ever existing.
Since most of
the species on earth do not even occur in the
CAN ANIMALS FROM THE
1) Some currently endangered species are very close to extinction because their numbers are so small (all of the following population estimates are from the mid-1990s):
--Schaus Swallowtail Butterfly: under 100
--Black Footed Ferret: 450
--Cooke’s Kokio: a Hawaiian tree that no longer occurs in the wild, fewer than 50 grafts still survive that have yet to produce seeds
--Flat Pocketbook Pearly Mussel: 9 small colonies
--Laysan Duck: 500
--Swamp Pink: 120 known sites
--Northeastern Beach Tiger Beetle: 45 groups
--Red Wolf: fewer than 300
--Macfarlanes Four-O’Clock: 10 patches
--Green Pitcher Plant: 26 known sites
--Hellers Blazing Star: 7 groups (most fewer than 50 plants)
--Na’u: 15 bushes
--Whooping Crane: 175
--Key Tree Cactus: under 200
--Boulder Darter (a small perch): 8 small groups
Wedge Mussel: 19 groups (some in
--Tenessee Purple Coneflower: 5 patches
There are a number of organisms on the Endangered
Species List that have not been seen in years/decades and may already
be extinct such as the turgid blossom, yellow blossom, little Mariana
fruit bat, Mariana mallard, scioto madtom. The Bachman’s warbler and Ivory billed woodpecker
are extinct from the
Some species that inhabited
WHY SHOULD SPECIES BE SAVED?
a) Conservationist reasoning: They are useful to humans.
1) Plants (especially in rainforests) and phytoplankton supply most of the world's oxygen and remove large amounts of carbon dioxide from the air. The climate will be altered without them.
2) Although seemingly insignificant, many small species are at the bottom of food chains and their loss impacts larger species.
The food supply: Most of the earth's crops come from 130 different plants;
most of these originated from 12 regions of the world where the wild ancestors
are still found. Geneticists often
look to these wild species once new strains of pests blight crops. When blights hit Columbian or Brazilian coffee
strains, new wild strains from the Ethiopian highlands were found. In the late 1970s, grassy stunt virus hit the
rice crop of southern and eastern
After searching all 6,500 varieties of barley,
the California Agricultural Lands Project found an Ethiopian strain resistant
to the yellow dwarf virus that now protects all of
4) Drugs: About 1/4 all
Other examples of drugs from plants include: bromelain (controls inflammation), codeine (analgesic), colchicine (anticancer), digitoxin (cardiac stimulant), diosgenin (source of female contraceptive), L-dopa (suppresses Parkinson's disease), ergonovine (migraines & hemorrhaging), glaziovine (antidepressant), indicine N-oxide (anticancer), menthol, morphine, quinine (antimalarial), reserpine (reduces high blood pressure), and scopolamine (sedative).
5) Defense from pests: The weed plants and insect pests which threaten food production and the insects which can spread disease have wild predators. For example, certain wasps stop borers from destroying sugar cane crops.
6) Ecotourism: The United Nations that about $230 billion/year in ecotourism. Many wild areas and animal species can generate far more income for a country through tourism than through their destruction.
b) preservationist reasoning: Every species has a right to exist and the all species contribute to the beauty of the world. Which of the species depicted in the images below could the world do without? Probably all of them. If any one of these species disappeared, life on earth would still exist and your life would probably continue unchanged. Which of the following species would you like to see lost from the world? Which of the following species do not add to the richness and wonder of the world? Which of the following species could be lost without the next generation regretting their loss?