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Narrator:Listen to part of a lecture in a biology class.
獨白:請聽下面生物課的一部分錄音。
Professor:Ok, I have an interesting plant species to discuss with you today.
教授:今天我們將要討論一種奇特的罕有植物品種:
Um…it's a species of a very rare tree that grows in Australia, Eidothea hardeniana,
它就是生長于澳洲的Eidothea hardeniana，
but it's better known as the Nightcap Oak.
也被稱為夜冠橡樹。
Now, it was discovered only very recently, just a few years ago.
直到近幾年人們才發現，
Um… it remained hidden for so long because it's so rare.
夜冠橡樹因其罕見而隱藏了很久，
There are only about 200 of them in existence.
目前存活個體僅有200株，
They grow in a rain forest, in a mountain rage…range in the north part of New South Wales which is a…er… state in Australia.
它們生長在澳大利亞新南威爾士州北部山脈的熱帶雨林區。
So just 200 individual trees in all.
所以目前存活個體僅有200株，
Now another interesting thing about the Nightcap Oak is that it is…it represents…er…a very old type…er…kind of tree that grew a hundred million years ago.
而夜冠橡樹的另一個奇特之處在于，它屬于某種存活于一億多年前的古老樹種，
Um, we found fossils that old that bear remarkable resemblance to the tree.
并與迄今發現的古老化石具有驚人的相似之處。
So, it's a primitive tree.
因此可以說它是原始植株，
A…a living fossil you might say.
你們也可以說它是活化石，
It's relic from earlier times and it has survived all these years without much change.
它是歷經億年風雨存活至今未曾改變的遺跡，
And it…it's probably a kind of tree from which other trees that grow in Australia today evolved.
而且人們甚至可以推斷，當今澳洲生長的諸多樹種都是由其進化而來。
Just to give you an idea of what we are talking about.
以上就是關于夜冠橡樹的簡介，
Here's a picture of the leaves of the tree and its flowers.
下面請同學們觀看一張它的樹葉和花朵的照片。
I don't know how well you can see the flowers.
我不知道大家是否能看清楚花朵，
They're those little clusters sitting at the base of the leaves.
那些位于樹葉底部的小花簇就是。
Okay, what have we tried to find out about the tree since we've discovered it?
夜冠橡樹在被發現后究竟有哪些謎題值得我們去探究呢？
Hum…or how…why is…is it so rare? That's one of the first questions.
首先，為何它如此稀少？
Um… how is it…um…how does it reproduce? This's another question.
另外，它是如何繁殖的呢？
Um, maybe those two questions are actually related. Jim?
也許這兩個問題是緊密聯系的。Jim你怎么看？
Student:Hum …I don't know.
學生:嗯，我不確定，
But I can imagine that…for instance, seed disposal might be a factor.
但我想種子的散播或許是影響橡樹繁殖的重要因素。
I mean if the…er…you know, if the seeds cannot really disperse in the wild area, then, you know,
如果夜冠橡樹的種子無法在廣闊區域內散播、生長，
the tree may not colonize new areas.
那么樹種就無法拓展新領域，
It can't spread from the area where it's growing.
因此其繁殖也就無法突破原生地的地理范圍。
Professor:Right. That's…that's actually a very good answer.
教授:好的，回答得很好。
Um, of course, you might think there might not be any areas where the tree could spread into, er…because…um…well, it's very specialized in terms of the habitat.
同學們或許認為夜冠橡樹能夠生存的區域很稀有，即它對生長環境的要求很獨特。
But, that's not really the case here.
但事實卻并非如此。
Um…the suitable habitat, that is, the actual rainforest is much larger than the few hectares where the Nightcap Oak grows.
實際上適合夜冠橡樹生長的熱帶雨林區面積廣闊，遠遠超過其現今存活的幾公頃范圍。
Now this tree is a flowering tree as I showed you.
現在展現給你們的是一株開花樹。
Um…um…it produces a fruit, much like a plum.
大家想想看，夜冠橡樹是開花植株，能夠結出梅子狀果實，
On the inside there's a seed with a hard shell.
其種子外包有堅硬的外殼。
It…it appears that the shell has to crack open or break down somewhat to allow the seed to soak up water.
只有在外殼被擊破或打碎的情況下，種子才能接觸到水分；
You know, if the Nightcap Oak remains…if their seeds remain locked inside their shell, they will not germinate.
你們清楚，如果夜冠橡樹仍然在，一旦種子被封閉在外殼內，那么發芽生長就無法實現。
Actually, the seeds…er…they don't retain the power to germinate for very long, maybe two years.
事實上，種子的發芽能力只能持續兩年左右，
So there's actually quite a short window of opportunity for the seed to germinate.
所以實際上種子開始發芽的機會少之又少。
So the shell somehow has to be broken down before this…um…germination ability expires.
因此夜冠橡樹的種子必須在此段時間內突破外壁。
And…and then there's a kind of rat that likes to feed on the seeds as well.
另外，當地某種鼠類喜歡以橡樹種子為食。
So, given all these limitations, not many seeds that the tree produces will actually germinate.
因此，由于以上原因，僅有少數夜冠橡樹種子能夠成功地發芽生長，
So this is a possible explanation for why the tree does not spread.
所以這是對于這種樹無法傳播的可能解釋。
It doesn't necessarily explain how it became so rare, but it explains why it doesn't increase.
這雖然不能解釋夜冠橡樹為何如此稀少，但或許可以說明為什么夜冠橡樹繁殖如此有限，以至于數量無法激增。
OK, so it seems to be the case that the species, this Nightcap Oak is not very good at spreading.
綜上所述，夜冠橡樹似乎并不是善于擴展領地積極繁殖的物種，
However, it seems, though we can't be sure, that it's very good at persisting as a population.
雖然我們不能夠肯定，但它的確是生命力極強的物種。
Um…we…there's some indications to suggest that the population of the Nightcap Oak has not declined over the last er…you know, many hundreds of years.
部分證據顯示，夜冠橡樹的數量在過去的數百年內都未發生明顯減少，
So it's stayed quite stable.
其個體數量極為穩定。
It's not a remnant of some huge population that is dwindled in last few hundred years for some reason.
因此，現存的200株并非數百年前豐盛繁殖的剩余，
It's not necessarily a species in retreat.
它也并不處于物種衰退期。
Ok, so it cannot spread very well, but it's good at maintaining itself.
可以說，夜冠橡樹繁殖力不強，但生命力強，
It's rare, but it's not disappearing.
它雖然稀少卻并不面臨滅絕的危險。
Ok, the next thing we might want to ask about the plant like that is what chances does it have to survive into the future.
那么接下來我們將要討論，夜冠橡樹一類的植物種群在未來得以存活的幾率有多大，
Let's look at that.
讓我們繼續分析。
