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描寫瀕臨危機動物的英語作文北極熊（精選5篇）
無論在學習、工作或是生活中，說到作文，大家肯定都不陌生吧，作文是經(jīng)過人的思想考慮和語言組織，通過文字來表達一個主題意義的記敘方法。怎么寫作文才能避免踩雷呢？以下是小編整理的描寫瀕臨危機動物的英語作文北極熊，僅供參考，希望能夠幫助到大家。
描寫瀕臨危機動物的英語作文北極熊 1
When the Arctic Ocean freezes over in the autumn, polar bears set off in search of their favorite meals: fatty ringed seals and bearded seals. By the summer, the sea ice begins to melt and break apart. Deprived of access to the tasty seals, polar bears spend the summer fasting. At least, thats whats supposed to happen. As the planet warms, the warmer ice-free season is getting longer and longer. So whats a hungry bear to do?
Scientists once thought that polar bears might survive by supplementing their pinniped diet by turning to terrestrial foods like snow geese, their eggs and caribou.
"Weve had this debate in the literature about whether terrestrial foods are nutritionally relevant to polar bears during the on-land season when the ice has melted."
University of Alberta biologist Nick Pilfold.
"And weve known for a long time, going back to research in the early 70s, even going to back to early explorer logs, that polar bears will consume terrestrial based foods. But the debate was always whether those foods actually add up, energetically." In other words, do these substitutes provide enough nutrition to make up for the lost seals?
To find out, Pilfold and his colleagues estimated the weight lost each day by polar bears in the wilds of western Hudson Bay during the ice-free season, when they could ostensibly be chowing down on terrestrial foods. Then they compared that to the weight lost by bears that are temporarily held in Manitobas Polar Bear Alert Program.
While captive, the bears do not eat. They drop about one kilogram each day. But the wild bears, who had access to the Arctic snack bar, lost the same amount of weight each day. The results are in the journal Physiological and Biochemical Zoology.
"Which is really saying that the terrestrial foods do not have dense enough energy to offset the mass loss. So this idea that bears can just switch from eating sea ice–based food to land food and thats going to help supplement against longer ice-free seasons, that really doesnt show up in the data."
The problem is that polar bears evolved to rely on the marine diet.
"The food on land is protein and carbohydrate based, and the food the polar bears really focus on is fat. Fat is the name of the game for these bears; theyre highly adapted to absorbing that fat into their system and putting it onto their body as body mass, so they can fast on it later on. And the only thing thats going to provide them with that type of fat are marine mammals. And they can only access those marine mammals when theres sea ice."
Adult males can go eight months without food. But younger, sub-adult bears, which are no longer nursing and must hunt, cant last as long without sea ice. So as the Arctic warms, younger polar bears will disproportionately die out. Leaving the species survival in doubt.
北冰洋在秋季結(jié)冰以后，北極熊就會出發(fā)去尋求它們最喜歡的食物：富含脂肪的海豹和胡子海豹。海冰在夏季開始融化斷裂。這使北極熊在夏季無法吃到美味的海豹，所以它們進入禁食期。至少，情況應(yīng)該是這樣。但是由于地球變暖，溫暖的無冰季節(jié)越來越長。那饑餓的北極熊要怎么辦?
科學家曾經(jīng)認為，北極熊可能會轉(zhuǎn)向陸地上的食物來補充它們對鰭足類動物飲食的需求，進而生存下去，這些陸地食物包括雪雁、雪雁蛋和北美馴鹿。
“文獻中有過這類辯論，即在寒冷融化時陸地食物是否能滿足北極熊的營養(yǎng)需求。”
尼克·皮爾福德是加拿大阿爾伯塔大學的生物學家。
“通過上世紀70年代初的研究，還有早期的探險者日志，我們很早以前就知道，北極熊會以陸地食物為食。但是辯論的焦點在于，這些食物是否能增加北極熊的能量。”換句話說，這些替代食物能否為北極熊提供足夠的營養(yǎng)，彌補不能進食海豹帶來的損失?
為了解開這個疑惑，皮爾福德及同事對西哈德遜灣荒野地區(qū)的北極熊在無冰季期間每天失掉的體重進行了估算，從表面上看，北極熊在這段時間食用了陸地食物。隨后，他們將這一數(shù)據(jù)與通過馬尼托巴北極熊預警計劃暫時捕得的北極熊所失掉的體重進行了對比。
在被關(guān)期間，北極熊不吃東西。它們的體重每天大約下降1公斤。雖然野生北極熊能享用北極“小吃”，但是它們的體重每天也同樣會下降1公斤。這一研究結(jié)果發(fā)表在《生理學和生化動物學》期刊上。
“顯然結(jié)果表明，陸地食物不能為北極熊提供足以抵消大量損失的.能量。所以，北極熊可以從食用海冰下面的食物轉(zhuǎn)向食用陸地食物，并幫助它們對抗日益延長的無冰季這個觀點，并沒有在這項數(shù)據(jù)中得到證明�！�
問題是，北極熊進化成了依靠海洋食物的動物。
“陸地食物以蛋白質(zhì)和碳水化合物為基礎(chǔ)，而北極熊需要的食物以脂肪為主。脂肪是這些熊真正需要的東西;它們高度適應(yīng)的情況是，將脂肪吸收進它們的系統(tǒng)中，然后把這些脂肪放在身上以增加體重，這樣它們之后就可以依靠這些脂肪來度過禁食期。唯一能提供給北極熊這種脂肪的就是海洋哺乳動物。但是它們只能在有海冰時食用到這些海洋哺乳動物�！�
成年北極熊可以8個月不進食。但是小一些的未成年北極熊已經(jīng)不再被哺育，它們必須要去獵食，可是它們不能在漫長的無冰季期間一直不進食。所以，隨著北極地區(qū)變暖，較小的北極熊將會大批死亡。這使這些物種的生存成為問題。
描寫瀕臨危機動物的英語作文北極熊 2
A triple bacon cheeseburger seems like a heart attack on a plate.
三層奶酪咸肉漢堡感覺吃完很容易讓人突發(fā)心臟病。
So how can polar bears thrive on their version, seal blubber?
那么,北極熊是如何處理這些高熱量食物的呢?
Turns out theyve stocked up on genes that let them clear fats from their blood.
結(jié)果顯示它們儲存在遺傳基因里的信息使得它們能夠清除血脂。
Thats according to a study in the journal Cell.
這是根據(jù)《細胞》雜志上的一篇研究得出的結(jié)論。
Polar bears are well adapted to life on the sea ice.
北極熊非常適應(yīng)在浮冰上的生活。
Up to half their body weights fat, which gives them extra insulation and buoyancy, and provides them with a ready source of energy.
幾乎占它們身重一半的'脂肪足以使它們保暖并且維持體力，提供給它們一種易轉(zhuǎn)化的能量。
But how can an animal so fat also be so fit?
但一種動物怎么能又胖又健康?
Researchers compared the genomes of polar bears with those of brown bears, and found that polar bears have accumulated genetic changes that boost their heart health and fat metabolism.
研究人員們通過比較北極熊和棕熊的基因，發(fā)現(xiàn)北極熊的基因組中積累了不少有利于心臟健康和脂肪代謝的遺傳突變。
One gene in particular, called ApoB, helps move cholesterol out of the blood—where it causes problems in humans—and into cells.
特別是編碼為載脂蛋白B的基因有助于清除血液中對人類有害的膽固醇轉(zhuǎn)變成細胞代謝。
These genomic changes happened quickly, evolutionarily speaking.
這些遺傳變化從進化的角度來講發(fā)生的十分快。
Polar bears and brown bears diverged from a common ancestor less than half a million years ago.
北極熊和棕熊都來自于同一個祖先，它們是在大約50萬年前左右開始向不同分支進化。
But if that seems super speedy, the ability to digest lactose didnt spread through human populations until we domesticated cows, just 10,000 years ago.
但是如果這種變化看上去十分快速的話，消化乳糖的酶逐漸進化到人類各個種群中也還是發(fā)生在大概1萬年前我們可以馴化乳牛之后。
A moooving testament to the power of natural selection.
這是自然選擇力量的證明。
描寫瀕臨危機動物的英語作文北極熊 3
The global polar bear population could decline by more than 30 percent in as little as 35 years. Thats according to a new study in The Royal Societys Biology Letters.
全球北極熊數(shù)量在35年內(nèi)可能下降超過百分之30。這是根據(jù)英國皇家學會生物學快報的一項新研究。
Researchers looked at climate change effect on the Arctic Sea and calculated the likelihood of this projected population drop is 71 percent.
研究人員觀察氣候變化對北極海的影響，并計算出預計種群下降的可能性為百分之71。
Thats because polar bears stand on Arctic Sea ice when hunting for seals. According to NASA, even the thickest ice in the Arctic Ocean has "either thinned or melted away."
這是因為北極熊捕獵海豹時站在北極海的'冰上。美國國家航空航天局表示，甚至北冰洋最厚的冰要么變薄或要么融化了。
And just this week, scientists reported sea ice levels in the area were at a record low for this time of year.
就在本周科學家報告稱，該地區(qū)的海冰水平創(chuàng)下一年中這個時候的歷史新低。
This all adds up to not great news for polar bears. With an estimated population of 26,000, the bears are already listed as a vulnerable species by the International Union for the Conservation of Nature.
這對北極熊不是什么好的消息。現(xiàn)估計有26,000頭北極熊，已被國際自然保護聯(lián)合會列為易危物種。
描寫瀕臨危機動物的英語作文北極熊 4
In the vast, icy expanse of the Arctic, there exists a magnificent creature whose survival has become emblematic of the growing ecological crisis - the polar bear. Known scientifically as Ursus maritimus, these majestic white giants are facing a plight that is both heart-wrenching and urgent.
Polar bears stand at the pinnacle of the Arctic food chain, playing a critical role in maintaining the balance of their ecosystem. However, their existence is under severe threat due to the rapidly melting ice caps caused by climate change. Their habitat, which once stretched across vast frozen oceans, is diminishing at an alarming rate. As sea ice retreats earlier each spring and forms later each autumn, polar bears are left with less time and space to hunt seals, their primary source of sustenance.
The image of a polar bear stranded on a dwindling ice floe has become a haunting symbol of the Anthropocene era. It depicts not just the struggle for survival of one species, but also a clarion call for global action against climate change. The narrative of the polar bears decline mirrors the larger story of biodiversity loss and the devastating consequences of human-induced environmental changes.
Moreover, the polar bears predicament underscores the interconnectedness of life on our planet. Their potential extinction could trigger a domino effect within the Arctic food web, impacting countless other species and exacerbating the overall health of the region.
Despite the grim outlook, hope persists. Conservation efforts are underway to protect polar bear habitats and curb greenhouse gas emissions. Education campaigns raise awareness about the impact of climate change on these magnificent creatures, inspiring individuals and governments alike to take decisive steps towards sustainability.
In conclusion, the polar bear’s fight for survival is a poignant reminder of our shared responsibility to safeguard the Earths ecosystems. Their plight serves as a stark warning that the future of all living beings, including our own, is intertwined with the fate of the polar bear. It is therefore imperative that we act now to mitigate climate change and preserve the Arctic habitat, not only for the polar bears sake but for the preservation of the delicate balance of life on our planet.
描寫瀕臨危機動物的英語作文北極熊 5
In the frigid, white wilderness of the Arctic, there roams a creature whose plight epitomizes the perils of climate change – the polar bear. This formidable and awe-inspiring species, Ursus maritimus, is grappling with an existential crisis that has escalated into a global call to action.
Polar bears are icons of resilience in the harshest of environments, yet they find themselves on the precipice of endangerment. Their existence relies heavily on the sea ice, which serves not only as their hunting ground but also as their platform for breeding and resting. Unfortunately, the relentless march of global warming has led to the accelerated melting of this icy habitat. The extended periods of open water each year severely limit the polar bears ability to hunt seals, thereby leading to malnutrition, lower reproductive rates, and in some cases, starvation.
The narrative of the polar bears struggle is one of stark contrast - from powerful predators stalking across the frozen expanse to emaciated figures pacing the dwindling remnants of ice. Their diminishing numbers serve as a tragic barometer of our planets health, indicating a profound shift in Earths ecosystems.
Moreover, the plight of the polar bear transcends its individual survival. It symbolizes the interconnectedness of all life forms within the intricate web of nature. As apex predators, their decline could trigger a cascade effect throughout the food chain, impacting countless other species that coexist within the Arctic ecosystem.
In conclusion, the polar bear’s fight for survival is a poignant reminder of the urgent need for global environmental conservation efforts. It is a call to action for humanity to recognize and address the consequences of our actions on these majestic creatures and the world at large. We must strive to mitigate climate change and preserve the integrity of their natural habitat, lest we lose not just the polar bear, but a significant piece of our planets irreplaceable biodiversity.
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