愛華網(wǎng)Idea：自然界中，每一種動物都是緊密聯(lián)系的。一種動物的減少消亡會直接影響其他動物，甚至整個生態(tài)系統(tǒng)。動植物對于醫(yī)學(xué)發(fā)展也起到了重要作用；另外，動物所創(chuàng)造的經(jīng)濟利潤也是驚人的。生物多樣性的好處體現(xiàn)在凈化空氣、凈化水源、扶貧、農(nóng)業(yè)等諸多方面。
Endangered Species... So What?
We know thatanimal species have appeared and disappeared continually since lifebegan on Earth. This is a natural phenomenon. However, specieshave been vanishing at a much faster rate for about a century nowthanks to human factors such as pollution, commercialoverexploitation, poaching and deforestation. Well, so what? Isit really that important to protect every species of animal on ourplanet?
Certainphilosophers and scientists keep repeating that if we don't savethe animals, how will we be able to save ourselves? A betterknowledge and understanding of animals gives us a betterunderstanding of our own species. The will to protectanimals and nature in general demonstrates the value of a society.And if the optimal development of our resources is a priority, itmust be achieved not only economically or socially, butenvironmentally as well. This is the vision of sustainabledevelopment, which dictates that we use our natural resourceswisely for the benefit and enjoyment of future generations.
But again, why the strenuous attempts to protect snakes,crocodiles, sharks, spiders, or even wolves and raptors? Because itdoesn't matter that an animal is ugly to look at, undesirable orpotentially dangerous, all animals play a role in nature andhave a right to survive. It's surprising to learn the servicesthey render us in return.
AQuestion of Balance
In nature, everything is interconnected. Unfortunately,we often have very little idea of all the repercussions involvedin the disappearance of a single animal population in a corner of aforest, swamp or river. Imagine the impacts of clear cuttingon the development of a new residential area or those offilling a swamp in order to build a road. Imagine thatpollutants are emptied into the mouth of a river. What wouldhappen? Obviously, the shrubs, trees, aquatic plants and algaewould be contaminated, die or disappear. Browsing animals wouldthen be obliged to leave the area owing to the lack of foodsources. Next, predators large and small would be deprived of theprey they need to survive. And so on and so forth.Disruption and imbalance are the hallmarks of a nature modifiedand remodelled by humans. And since every animal plays a specificrole in the food chain and the balance of nature, the entirenatural world would be turned on its head. To illustrate each one'srole in the environment, let's make an analogy with the Egyptianpyramid. Each animal species is represented by a stone block. Ifone block is removed from the base, nothing happens. The pyramidremains solid enough thanks to all the other blocks. But if severalblocks are removed at random, the edifice becomes fragile. At somepoint the removal of a single block becomes too much and the entirestructure crumbles. The same holds true for the pyramid of life.All species are necessary to maintain this fragile equilibrium innature, even if their role is not immediately obvious.
The following is a good illustration of the bonds linking animalspecies. Strange as it may seem, the Killer Whale affects the dietof the Bald Eagle in Alaska! Researchers have found that anincrease in Killer Whales results in a decrease in Sea Otters, oneof their favourite prey items. Otters, for their part, eat seaurchins. Therefore, the fewer otters, the more sea urchins thereare. Sea urchins feed on the large algae that serve as hidingplaces for fish and invertebrates along banks. Thus, the more seaurchins, the fewer algae and...the fewer hiding places! As aresult, the fish move elsewhere. In Alaska, Bald Eagles are raptorswho subsist mainly on the fish in shallow waters on the edges ofthe ocean. Without these fish, they have to find other food.ordingly, scientists discovered that the decline of Sea Otters inAlaska thanks to the predation of Killer Whales, forces Bald Eaglesto change their diet and choose marine birds as prey. A puzzleindeed!
Nature,Source of Life
Man has produced a thousand and one inventions while observingnature. Think of Leonardo da Vinci, who drew flying machines ashe watched the flight of bats. In the area of human health,animals and plants often show us the way to stay in shape.Take, for example, Chimpanzees, who consume various plants totreat health disorders (digestive problems, bouts of malaria,parasites...). They have learned to consume the right plants in theright doses for the right ailments! Is it possible we'lldiscover new medicines thanks to Chimpanzees?This is whatthe veterinarian Sabrina Krief affirms since studying the behaviourof these primates in Uganda. It is, therefore, to humans' advantageto save this monkey and the some 190 species of primates thatpopulate the tropical forests of Asia, Africa and SouthAmerica.
Nature can be viewed as a huge pharmacy; it contains thousandsof components essential to man's survival. Therefore, the animalworld is in a way part of our survivalkit.眾多例子證明動物對醫(yī)學(xué)發(fā)展的重大貢獻(xiàn)，都可以用到作文中： Used since the nineteenthcentury, leeches are now employed in surgery because of theanticoagulant and anti-inflammatory properties of their saliva.The active elements of the Brazilian Viper's venom have beensynthesized into a medication that controls blood pressure.Scorpion venom is used in research on brain tumours.Sharks contribute to studies of muscle degeneration and certainforms of cancer. Bee honey improves human health by targeting andattacking certain microbes in our organism. One of only twopoisonous lizards on earth, the Gila Monster secretes a substancein its venom that may help treat diabetes. Finally, the study of aspecies of African frog, Xenopus laevis, was found toproduce a molecule useful in preventing infections from bodylesions. Scientists focus on these frogs in their research on theAIDS virus (acquired immunodeficiency syndrome). Imagine thepotential of the 5,500 frog species which, for the most part, don'tall produce the same molecule! We could find a host of remediesfor all kinds of aches and pains. Unfortunately, amphibiansare declining rapidly thanks to pollution, habitat destruction andclimate change. In 2008, scientists declared that more than a thirdof the planet's amphibians were seriously at risk.
Plants also play a crucial role in our health. Of the 150medicines most frequently prescribed, about a hundred are derivedfrom plants. Happily, many of the active ingredients inthese plants can be synthesized in the laboratory. This is the casefor aspirin, which comes from the willow tree. On the otherhand, it's impossible to synthesize the anti-cancer molecules inthe Ground Hemlock. This shrub must be harvested in order toextract its benefits. Certain specialized companies have received amandate to do this.
AnImportant Economic Engine for Canada
Did you know that over 85% of Canadians believe in the importanceof nature and are in favour of protecting endangered species?Economically, this represents more than 20 million Canadians whospend billions of dollars a year to practice "nature" activitiessuch as mountain hiking, camping, fishing, hunting, photography,bird watching and visits to zoos or nature centres. What'smore, thousands of Canadians earn their living from flora andfauna. There's also the tourism industry, which attractsmany travellers to Canada thanks to the beauty of its forests, thesplendour of its mountains and the majesty of its lakes andrivers. Let's keep our eyes on OUR nature and safeguardthese precious jewels.
Then again, why not protect animals simply because they'reBEAUTIFUL? A butterfly that delicately alights on a flower; achickadee that pecks at the seeds in your birdfeeder; frogs thatsing during mating season in springtime; a Moose that emerges fromthe mist close to your campsite... Even animal species not atrisk need your support. If humans don't take action to keep ourplanet "green and blue", hundreds of species will be gone 50 yearsfrom now, while those currently abundant will merit the status ofendangered species in 2050 – an unenviable fate. As inhabitantsof the Earth, we must take measures to reverse this trend,for we are the ones responsible for the ecological disorder. Overthe next decades, therefore, we must step up efforts to ensure thatour grandchildren, like ourselves, will have the opportunity toenjoy nature in all its glory.
Why protect biodiversity and save endangeredspecies?
Biodiversity is the variety of life (its ecosystems, populations,species and genes). Saving endangered species (plants and animals)from becoming extinct and protecting their wild places is crucialfor our health and the future of our children.
As species are lost so too are our options for future discoveryand advancement. The impacts of biodiversity loss include clearlyinto fewer new medicines, greater vulnerability to naturaldisasters and greater effects from globalwarming.
Biodiversity provides us with tremendous vital benefits:
Air Purification
Forests filter particulates and help regulate the composition ofthe atmosphere and purify our air. Loosing forest around the worldincreases air pollution.
Poverty Alleviation
Biological diversity provides the world's population, particularlythe poor, with food, medicines, building materials, bioenergy andprotection against natural disasters.
Health
Of the medicines currently available, about 50% are derived fromnatural products. At least 120 chemical compounds, derived from 90plant species, are important drugs currently in use in manycountries around the world! By loosing biodiversity, we are losingthe chance to discover new medicines that could end the sufferingof millions of people and save national economies billions ofdollars each year.
Purification of Fresh Waters
Nitrogen pollution became a serious problem many parts of theworld. Protecting and restoring wetlands to reduce nitrogen loadingis less expensive than the construction of wastewater treatmentplants. Wetlands contain exceptional biodiversity and generatecritical services such as purification of fresh waters. They alsosupport the livelihoods of localcommunitie.
Agriculture
Many of the benefits of biodiversity rue to agriculture itself. Forexample, the marine environment is a source for insecticides.Nereistoxin is an insecticidal poison isolated from the marineworm, Lumbrineris brevicirra. Others benefits include croppollination, soil fertility services provided by microorganisms,and pest control services provided by insects and wildlife.Biodiversity loss has important implications foragriculture.
Mitigation of Floods
Floodplains are ecosystems that border rivers subject to flooding.Following excessive rains, flood waters flow over riverbanks andinto these floodplainforestsand wetlands. Some of the water is soaked up by thesoil.
Pollination of Crops and NaturalVegetation
Many flowering plants rely on animals to help them mate by ensuringfertilization. Bees, butterflies, beetles, hummingbirds, bats, andother animals transport pollen, the male reproductive structures,from one plant to another, with enormous benefits to humanity.Approximately one third of the world’s food crops depends on thesenatural pollinators. In the U.S., honeybees pollinate about U.S.$10 billion worth of crops.
Carbon Sequestration
Carbon storage (sequestration) urs in forests and soils primarilythrough the natural process of photosynthesis. The movement ofcarbon in and out of trees and soils is part of the Earth's globalcarbon cycle. Forests and coral reefs contain massive carbonreservoirs, which significantly contribute to regulating the globalclimate.
Buffering the Land against OceanStorms
Mangrove forest protect coastlines against Vegetated banks bind thesoil, preventing erosion caused by wave and surface waterflow.
Preservation of SoilFertility
Soils, with their active microbial and animal populations, have thecapacity to supply adequate nutrients to plants in suitableproportions. Natural forest soil had a higher content of totalnutrients and biomass.
Aesthetics and Spiritual
The natural world is beautiful and valued for its aesthetic appeal.Loss of biodiversity impoverishes our world of natural beauty andwonder, both for ourselves and for the futuregenerations.
