時(shí)差N小時(shí):南極森林
親愛的科學(xué)一刻，我知道大約在2.5億年前，地球要比今天熱的多的多。
So I'mwondering what that meant, exactly?
所以，我就在想這到底意味著什么?
How did the planet look different than it does today?
那時(shí)的地球相比今天而言有多大的不同呢?
Well, the Earth was different in lots of ways hundreds of millions of years ago.
幾億年前的地球與今天相比在很多方面都有所不同。
One majordifference linked to warmer global temperatures was that Antarctica was not the icy,barrenwasteland it is today.
最主要的一個(gè)差異與全球溫度有關(guān)，那就是南極當(dāng)時(shí)并不像今天這樣是一片被冰雪覆蓋的荒蕪之地。
In fact, it was covered by forest.
事實(shí)上，當(dāng)時(shí)的南極是一片森林。
What kind of forest?
什么樣的森林呢?
That's what scientists are trying to figure out.
科學(xué)家們也在試圖尋找答案。
Fossilized leaf impressions seemto show that mats of leaves once covered the ground.
從樹葉化石的痕跡來看，當(dāng)時(shí)的地表被層層的樹葉所覆蓋，
That suggests that the trees weredeciduous, meaning that they shed their leaves at the sametime.
這說明樹木會(huì)在每年的相同時(shí)間內(nèi)落葉。
But fossilized wood from theregion tells a different story.
但是該地區(qū)的木化石卻又說明了另一種情況。
Cells in the tree rings show a pattern of growth that's consistent with evergreen trees,meaning trees that don't shed their leaves.
年輪的細(xì)胞體現(xiàn)出樹木的生長(zhǎng)方式與常青樹相同。也就是說它們不會(huì)落葉。
So the ancient Antarctic forests were probably a mix ofevergreen and deciduous trees.
因此，古代的南極森林可能是一片常青樹和落葉樹的雜交林。
Analysis of carbon molecules in the fossil woods shows something similar.
對(duì)木化石中碳分子的分析結(jié)果也顯示有所相似之處。
And it also suggests that the forests have some similarities to tropical forests today.
同時(shí)，分析結(jié)果還表明了南極森林和今天的熱帶雨林也存在一定的相似。
Another question is how Antarctic forests dealt with constant daylight half the year and neartotaldarkness the other half.
另一個(gè)問題就是南極森林是如何適應(yīng)極晝和極夜現(xiàn)象的。
Wouldn't that mess with their ability to photosynthesize?
這難道不會(huì)擾亂它們光合作用的能力嗎?
More research might reveal the answer.
想要找出答案可能還需要進(jìn)行更多的研究。
