Ancestor of humans not so brainy
A monkey-like animal seen as an ancestor of monkeys, apes and humans was not as brainy(1) as expected, according to scientists who analyzed its nicely preserved 29-million-year-old skull.
The finding indicated that primate(2) brain enlargement evolved later than once thought, the researchers said on Monday.
They analyzed a remarkably well-preserved fossilized(3) skull of the little primate Aegyptopithecus(4) zeuxis, which lived in the trees and ate fruit and leaves about 29 million years ago in warm forests in what is now an Egyptian desert.
A technique called microcomputerized tomography(5) scanning a computerized X-ray method also called micro-CT allowed them to determine the dimensions of the animals brain.
What was astonishing is how small this brain is, Duke University primatologist Elwyn Simons, who led the study in the Proceedings of the National Academy of Sciences, said in a telephone interview.
You can also see its a pretty darn primitive brain. It would be small for a monkey or an ape, Simons added. So its telling us that the speed of achievement of brain enlargement in primates was a little slower than perhaps we had thought.
This skull of a small female was uncovered in a quarry(6) southwest of Cairo in 2004. It was better preserved than another skull of a larger male of the species found in the same area in 1966.
Based on earlier finds, scientists had theorized the species had a relatively large brain. Instead, it had a brain that might have been even smaller than that of a modern lemur, a primate with primitive traits.
Simons said that when this primate lived, Africa was an island, limiting the competition for survival. Simons said brain enlargement may have evolved in this lineage after Africa became connected to Asia, bringing in more animals including new and dangerous predators.
Brain-volume enlargement is favored under conditions of competition because you need to be smarter, Simons said.
1. brainy:有头脑的,聪明的
2. primate:灵长类动物
3. fossilize:变成化石
4. aegyptopithecus:埃及猿
5. tomography:X线体层照相术,能够照出某确定物体上事先规定好的某层部分,而不会照下其它部分的像
6. quarry:采石场科学家对一个保存良好的2900万年前的头骨进行研究,发现这种类猴的猴子、猿和人类祖先并没有预想得那么聪明。
周一,研究人员们说此发现显示灵长类大脑进化时间比原来认为的要晚。
这个小巧的古埃及猿头骨化石保存十分完好。此种灵长类动物生活在2900万年前的温暖埃及丛林,以树为家,以果为食,但是现在这片丛林已经变成沙漠了。
一项被称为微型电子计算机X线断层扫描的技术可以帮助测算动物大脑尺寸,它也可被称为微CT.
杜克大学灵长类动物学家Elwyn Simons在电话采访中说:我们很惊讶它的大脑竟然如此之小。 由他负责的本次研究被刊登在美国国家科学院报中。
Simons说:它虽然是一个灵长类头骨,但是比猴子或者猿的都要小。也就是说灵长类动物大脑的飞速发展比我们原来推算的要慢一点。
这个小的女性头骨在2004年被发掘于开罗西南部一个采石场中。它的保存状况好于1966年在同一地点发现的另一个稍大的同类男性头骨。
根据之前的研究,科学家们推断这种动物应该拥有相对大的大脑。但是它的大脑却比具有原始特点的现代狐猴的还小。
Simons说这种动物生活的时候非洲还是一个岛屿,没有生存竞争。Simons认为他们的大脑发展发生在亚非大陆相连的时候,因为很多动物包括新的和危险的食肉动物都来到了这里。
他说:竞争促进脑容量的扩展,因为你如果不变得更聪明就得死。
上一篇: 雅思阅读文章:儿童顺从与成长
下一篇: 雅思阅读判断题解题方法:镜像法
体坛英语资讯:Chinese starlet Wang Zongyuan dominates mens 1m springboard heat in his 1st FINA World Cha
国内英语资讯:China fast tracks approval of 65 items of medical equipment
国际英语资讯:Trump signs two-year budget deal to boost spending, lift debt ceiling
嗓音低沉者更具“领导风范”
国际英语资讯:EU nominates Bulgarias Georgieva as its candidate for next IMF chief
宠爱女孩儿的20条理由
浪费生命、蹉跎人生的50件事II
英众多父母为孩子储存脐带血
On Go to Study Abroad at Young Age 论年幼留学
My Favorite City—Zhuhai 我最喜欢的城市——珠海
国内英语资讯:RCEP negotiations make significant headway in Beijing
体坛英语资讯:International marathon along Yellow River to start in September in NW China city
健康人都有什么好习惯?
双语小说阅读:《谁动了我的奶酪》(7)
英发现世界最小化石 长度不到五分之一毫米
国内英语资讯:Root cause of fentanyl issue does not lie with China: FM spokesperson
国内英语资讯:China attaches great importance to cooperation with UN: envoy
娱乐英语资讯:Around 57,000 people attend Jennifer Lopezs 1st concert in Israel
最老牌的美国热狗是哪一家?
冬季如何搭配好围巾呢?
国内英语资讯:China to promote pooled procurement of expensive medical consumables
国内英语资讯:Hong Kong society strongly condemns act of flinging Chinese national flag into sea
国内英语资讯:China urges Western nations not to intervene in Hong Kong affairs
国内英语资讯:China competitions for Intl Army Games 2019 kicks off
体坛英语资讯:Thunder trade Westbrook to Rockets for Chris Paul
让动物长出人类器官?日本人兽杂交胚胎实验获批
哪种坐姿最正确?这取决于你做的是哪种工作
国内英语资讯:China warns of production safety in summer
国内英语资讯:Commentary: Blaming China for US fentanyl issue totally unacceptable
智商高的女性更易在三十多岁时吸毒