Palaeontology
Not guilty？
Humans are not always to blame when big animals go extinct
The Economist| August 15th 2020
一直以来，物种灭绝与人类脱不了干系这样的想法深入人心。但是，近期有研究人员表示：其实人类是无罪的。那么人类真的就无罪了吗？
词汇：
palaeontology n. [古生]古生物学
palaeo-表示“古，旧”之义，如：palaeogenetics
not guilty[法]无罪（declared not guilty of a specific offense or cime; legally blameless）
eg: He pleaded that he was not guilty. 他申辩自己无罪。
be to blamevi. 该受责备（应负责任）
背景介绍
恐鸟（moa）
恐鸟是数种新西兰历史上生活的巨型而不能飞行的鸟之一，由英国著名解剖学家欧文命名，意为“令人恐惧的大鸟”。恐鸟是一种完全没有翅膀的鸟，运动主要靠强而有力的大腿。有一条很长的脖子，就好像鸟雀中的长颈鹿。恐鸟一般被认为在18世纪中期数量飞速下降，到了1800年代几乎踪迹全无，估计于19世纪50年代左右彻底灭绝。关于恐鸟的绝种，主要认为跟毛利人的波利尼西亚祖先的捕猎和开垦森林有关。
渡渡鸟（Dodo）
渡渡鸟(Raphus cucullatus)，或作多多鸟(Dodo)，又称毛里求斯多多鸟、愚鸠、孤鸽，是仅产于印度洋毛里求斯岛上一种不会飞的鸟。这种鸟在被人类发现后仅仅200年的时间里，便由于人类的捕杀和人类活动的影响彻底灭绝，堪称是除恐龙之外最著名的已灭绝动物之一。也是毛里求斯唯一被定为国鸟的已灭绝鸟类，渡渡鸟于1681年灭绝。
【谚】As dead as a dodo. 死透了；早就过时了。
That hairstyle isas dead as a dodonow.
披毛犀（woolly rhinoceros）
又称长毛犀牛（an extinct two-horned Eurasian rhinoceros that was adapted to the cold periods of the Pleistocene, with a long woolly coat）因全身披满厚厚的毛而得此名。披毛犀有两只扁平的角，可以推开雪来吃草。它亦有一层厚厚的毛皮及脂肪，用来在寒冷中保持温暖。披毛犀生存于更新世时期，与真猛玛同一时代，并度过冰河时期存活了下来，活跃在欧亚大陆北部。披毛犀曾是旧石器时代人类的狩猎对象，它的灭绝年代至21世纪只有10000年，是最晚灭绝的史前犀。
01
From the moa in New Zealand to the dodo in Mauritius, the arrival of humans has often spelled extinction for tasty but previously isolated animals. Many scientists had assumed that the woolly rhinoceros, a shaggy beast that sported an enormous horn, suffered the same fate. The animal was common in northern Europe and northern Asia 30,000 years ago, when the first humans arrived. Shortly after, it disappeared.
词汇：
spell vt. 招致，带来（不好的结果）；意味着
tasty adj. 美味的，可口的
shaggy adj.蓬松的；表面粗糙的；毛发粗浓杂乱的
sport v. 穿戴；蓄留；展示（特殊或引人注目的东西）[with obj.] (wear or display (a distinctive or noticeable item))
eg: He was sporting a huge handlebar moustache. 他留着巨大的翘八字胡。
从新西兰恐鸟到毛里求斯渡渡鸟，人类的到来对于从前与世隔绝但肉质鲜美的动物来说常常意味着灭绝。很多科学家曾经认为披毛犀（一种长有巨角、毛发浓密的野兽）也遭遇了同样的命运（因人类猎杀而灭绝）。在三万年前，第一批人类到达时，这种动物遍布于欧亚大陆北部。但它们不久后便消失了。
02
But Love Dalén, a professorat the Centre for Palaeogenetics inStockholm, and Edana Lord, one of Dr Dalén’s PHD students,are not so sure. In a paper published in Current Biology, they use data from ancient DNA to argue that, this time at least, humans might be innocent.
词汇：
Palaeogenetics n. 古遗传学
Stockholm 斯德哥尔摩（瑞典首都）
Current Biology《当代生物学》，由美国细胞出版社出版（1991年至今），内容涵盖生物学各个领域的科学期刊，尤其是分子生物学，细胞生物学，遗传学，神经生物学，生态学及进化生物学等各领域。
但斯德哥尔摩古遗传学中心的洛夫·戴伦（Love Dalén）教授和他的一位博士研究生埃达娜·洛德（Edana Lord）却不这么认为。在《当代生物学》（Current Biology）上一篇论文中，他们使用了来自远古DNA的数据来论证这一观点。至少这一次，人类可能是无罪的。
03
Until recently, information on the fate of the great ice-age mammals had been limited to what could be gleaned from fossilised bones. While useful, bones can only tell you so much. They can reveal the number of animals of different ages present at a specific location at a specific time. With some species sex can be determined. Occasionally the cause of death can be detected.
词汇：
glean vt. 收集（资料）
be gleaned from 从……收集
fossilissed bones骨化石
直到最近，有关大型冰河时期哺乳动物的信息仅来自于骨化石。虽然有用，但也只能告知我们这么多。它们可以揭示出在特定时间、特定地点出现的各年龄段的动物数量。某些物种的性别也能得到确定。偶尔还可查出该动物的死亡原因。
04
In the past couple of decades, though, scientists have learned to tap another, richer source of information: ancient genomes. By itself, DNA degrades quickly, attacked by water and sunlight. But DNA encased within bones and teeth can survive for longer, especially if those bones and teeth are themselves encased in permafrost. It was this sort of DNA that enabled Dr Dalén and Ms Lord to investigate the woolly rhino’s disappearance.
词汇：
tap v. 利用，开发，发掘（已有的资源、知识等） ~(into) sth. to make use of a soure of energy, knowledge, etc. that already exists.
eg: We need to tap the expertise of the people we already have. 我们需要利用我们现有人员的专业知识。
degrade vt./vi. （使）降解；（使）降级
encase vt. 把……放入盒内；把……装箱
permafrost n. （如极地的）永久冻土
It is … that … 强调句，用于强调 is 和 that 之间的成分
eg: It is your hard work that matters.
然而，在过去几十年中，科学家们已经学会利用另一种包含更丰富信息的物质：远古基因组。就其本身而言，受到水和阳光的影响，DNA降解得很快。但是，包裹在牙齿和骨骼中的DNA就可以保存得更久，尤其当它们（骨骼和牙齿）封存在永久冻土中时。正是这种DNA让戴伦教授和洛德女士得以调查披毛犀消失的原因。
05
Working with ateam of colleagues, the researchers obtained DNA from 12 woolly rhinoceros bones collected from permafrost in Siberia, dating from the beginning of the Late Pleistocene, about 130,000 years ago, until the animals were on the verge of extinction. Extra DNA was recovered from one sample of rhino hair and one piece of tissue found in the stomach of a frozen wolf that had been preserved by the cold.
词汇：
on the verge of extinction濒临灭绝
SYM：be on the verge of = be close to = on the brink of = on the edge of + extinction
tissuen. 生理组织（part of an organism consisting of an aggregate of cells having a similar structure and function）
经团队合作，研究人员（戴伦教授和洛德女士）从西伯利亚永久冻土中采集到的12根披毛犀骨骼中提取到了DNA。这些骨骼可追溯到大约13万年前的晚更新世初期至其濒临灭绝。另一个DNA样本来自于一只被永冻土封存的狼，他们在这只冻狼的胃中发现了犀牛毛发及组织样本。
06
Analysing the genetic diversity of the samples allowed the researchers to make a rough calculation ofthe size of the woolly rhino population over time. Rather than declining as humans arrived, the population remained stable from 29,000 years ago until 18,500 years ago, just a few thousand years before the species went extinct.
词汇：
over time随着时间的推移
通过分析样本的多样性，研究人员可以对披毛犀种群数量的大小进行粗略计算。研究结果表明，从29000年前到18500年前，也就是披毛犀灭绝的几千年之前，该物种数量一直保持稳定，并没有因为人类的出现而减少。
07
That suggests that, far from being hunted to extinction, the rhinos co-existed stably with humans for around 10,000 years. Perhaps the people who encountered the beasts found them unpalatable. Or perhaps the rhinos were simply too dangerous to hunt with their simple weapons. (They were the size of the modern white rhino, which is not an animal that takes kindly to being stabbed withspears.)
词汇：
unpalatable adj. 不好吃的；味道差的
stab vt./vi. 刺，扎；刺入，刺伤
spear n. 矛；枪
这表明披毛犀与人类共处了一万年左右，并没有因猎杀而灭绝。或许是对其猎杀的人类发现它们并不可口。又或许只是用当时如此简易的武器去猎杀它们太过危险。（它们的体型同现代白犀牛一般大，不易被矛刺伤。）
08
Theresearchers’ case is not quite conclusive. It ispossible that some sort of technological advance eventually gave ancient humansthe ability to hunt rhinos safely, and that extinction followed after that breakthrough. On the other hand, the animals’ decline lines up suggestively with a rapid bout of global warming that began around 14,700 years ago.The researchers argue that this was the more likely cause of the animal’s disappearance. This time, it seems, it was Mother Nature whodunnit.
词汇：
conclusive adj. 确定的；毫无疑问的；不容置疑的
line up与……对齐
suggestively adv. 让人想起……地；引起联想地；暗示地
bout n. 一次；回合
whodunnit n. 侦探小说（who has done it 的缩写）（a story about a crime (usually murder) presented as a novel or play or movie）
但这一案例又缺乏一定的说服力。有可能某种技术的进步最终让远古人类拥有了安全猎杀犀牛的能力，而这一突破导致了它们的灭绝。从另一方面来说，该物种数量锐减时期让人联想到大约14700年前开始的一轮全球变暖。研究人员表示，这（全球变暖）更有可能导致物种消失。这一次，似乎大自然才是真凶。
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