字神帝國英語天地

今日主題：Polar Bear Rapid Evolution Lets Them Be Fat Fit
北極熊的快速進化使他們能夠在肥胖中維持健康

洪欣老師推薦：托福聽力最好的課外教材：60-Second Science
康康精選托福會考的主題，堅持每天精聽一定會進步的哦!!

建議方法：
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍，直到寫出85%以上的字)
3. 最後check文稿，看哪聽不出來，單字沒背過，還是發音不熟。
4. 堅持天天聽，就能每天進步哦。

MP3音檔 (按右鍵可下載聽)：喜歡的同學，幫忙推或按讚哦~~
http://online1.tingclass.net/voaspe/…/20140523sa_science.mp3

只有音檔怎夠，聽不懂地方，不用怕，康康幫你準備好中英文稿了：

中英文稿：
A triple bacon cheeseburger seems like a heart attack on a plate. So how can polar bears thrive on their version, seal blubber? Turns out they’ve stocked up on genes that let them clear fats from their blood. That’s according to a study in the journal Cell. [Shiping Liu et al,Population Genomics Reveal Recent Speciation and Rapid Evolutionary Adaptation in Polar Bears]
一個三層培根芝士漢堡看來像是餐盤上引發心力衰竭的元兇。那麼，北極熊是如何處理他們吃的高熱量食物的呢？原來，它們存積了（某種）基因讓它們能夠清除血 液中的脂肪。以上出自《細胞》期刊。【shiping Liu等著，《以北極熊為例，以動植物總群基因學揭示近代物種的快速進化適應性（進程）》】。

Polar bears are well adapted to life on the sea ice. Up to half their body weight’s fat, which gives them extra insulation and buoyancy, and provides them with a ready source of energy.
北極熊對生活在海面冰層具有良好適應性。重占體重一半的脂肪層給北極熊提供了額外隔離保護和浮力。同時，脂肪層也是北極熊重要的/主要的能量來源。

But how can an animal so fat also be so fit? 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. One gene in particular, called ApoB, helps move cholesterol out of the blood—where it causes problems in humans—and into cells.
但是，動物是如何做到在肥胖和健康並存的？研究人員把北極熊和棕熊的基因組進行了對比，發現北極熊的累積基因變化促進了它們的心臟健康和脂肪的新陳代謝。特別要指出的是一種叫ApoB的基因，它有助於把血液中，會給人類帶來健康隱患的膽固醇轉移到細胞中。

These genomic changes happened quickly, evolutionarily speaking. Polar bears and brown bears diverged from a common ancestor less than half a million years ago. But if that seems super speedy, the ability to digest lactose didn’t spread through human populations until we domesticated cows, just 10,000 years ago. A moooving testament to the power of natural selection. —Karen Hopkin。
這些帶有物種進化意義的基因變化通常發生得迅速。北極熊和棕熊從共有祖先，到兩者發生（基因）分歧，期間不足一百年時間。 但是，如果這（進程）看起來非常迅速，那從人類馴養乳牛到 ‘人類有能力消化乳糖’（這種認知）的普及，那也僅有一萬年時間。（以上其實）都是自然選擇力的持續見證。