时间:2019-01-12 作者:英语课 分类:2007年VOA标准英语(七月)


英语课
By Jessica Berman
Washington
19 July 2007

The origin of modern humans has been a heated topic among anthropologists, who have debated whether modern man came from Africa or somewhere else.   Now, researchers say they have they have proof beyond dispute of the so-called "out of Africa" theory.   VOA's Jessica Berman reports.


The "out of Africa" theory holds that modern humans emerged from the continent some 50,000 years ago, replacing more primitive 1 species including Neanderthals that existed on different continents.


The alternative theory, called the multiregional hypothesis, is that modern humans evolved from primitive species in many places around the world.


But in the 1990s, the multiregional hypothesis was largely discredited 2 by the advent 3 of genetic 4 testing.


Still, biologist Andrea Manica of Cambridge University in England says there are anthropologists who believe in the multiregional theory. 






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She says that is because of differences in the appearance, or morphology, of primitive human skulls 6 that have been uncovered on different continents.


"What we did, which I think really in a way brings the whole discussion slightly to a close, is actually to look at genetics and skull morphometrics at the same time with a single sort of framework," she explained.  "And actually show that if you ask the question explicitly 7, 'Do we come from Africa?'  Then the answer is yes no matter whether you look at genetics or whether you look at morphometrics."


Manica and colleagues measured 4,500 ancient human skulls from more than 100 populations around the world.  She says the size and shape of the skulls were compared to those unearthed 8 in Africa, which she says has a very diverse population.


"You find for example in terms of skulls, quite of a lot of variability on the traits," she added.  "You know, how broad faces are and how narrow and deep, and so on."


The investigators 9 discovered that the greater the distance from Africa, the less variability there was among the skulls.


"So, if you take skulls from a population in Africa, there is lots of variability," she noted 10.  "If you go to Europe, there's a little bit less.  If you go to Asia, it's going further down.  If you go then to North America, it goes further down.  And South America is really the most homogeneous in a way of [set] populations."


Manica says that the modern humans who left Africa were far less diverse than the human ancestors who remained behind.  And those that traveled further afield were physically 11 even less diverse, contributing to more physical uniformity on the continents where they settled. 


The study of the origins of modern humans appears in the current issue of the journal Nature.




adj.原始的;简单的;n.原(始)人,原始事物
  • It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
  • His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。
不足信的,不名誉的
  • The reactionary authorities are between two fires and have been discredited. 反动当局弄得进退维谷,不得人心。
  • Her honour was discredited in the newspapers. 她的名声被报纸败坏了。
n.(重要事件等的)到来,来临
  • Swallows come by groups at the advent of spring. 春天来临时燕子成群飞来。
  • The advent of the Euro will redefine Europe.欧元的出现将重新定义欧洲。
adj.遗传的,遗传学的
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
n.头骨;颅骨
  • The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
  • He fell out of the window and cracked his skull.他从窗子摔了出去,跌裂了颅骨。
颅骨( skull的名词复数 ); 脑袋; 脑子; 脑瓜
  • One of the women's skulls found exceeds in capacity that of the average man of today. 现已发现的女性颅骨中,其中有一个的脑容量超过了今天的普通男子。
  • We could make a whole plain white with skulls in the moonlight! 我们便能令月光下的平原变白,遍布白色的骷髅!
ad.明确地,显然地
  • The plan does not explicitly endorse the private ownership of land. 该计划没有明确地支持土地私有制。
  • SARA amended section 113 to provide explicitly for a right to contribution. 《最高基金修正与再授权法案》修正了第123条,清楚地规定了分配权。 来自英汉非文学 - 环境法 - 环境法
出土的(考古)
  • Many unearthed cultural relics are set forth in the exhibition hall. 展览馆里陈列着许多出土文物。
  • Some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。
n.调查者,审查者( investigator的名词复数 )
  • This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
  • The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》
adj.著名的,知名的
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
adj.物质上,体格上,身体上,按自然规律
  • He was out of sorts physically,as well as disordered mentally.他浑身不舒服,心绪也很乱。
  • Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。
学英语单词
acquired tendency
afforestation station
Agago
Andreyevskoye, Ozero
aphis ichigocola
arnolds of brescia
at&t global network services
beds us
bethenod-latour high frequency generator
blue-heat
calcium-magnesia phosphate fertolizer
capacity for heat
carbon filament atomiser
cermets ceramic metals
colloidox
cringes
degree program
diphtberia antitoxin unit
discretionary heavier punishment
distance increment
Dominating enterprise
Dontostemon integrifolius
Empoasca pirisuga Matsumura
epilobium canums canums
exoneree
explicit prompt
first-dose
fluidane
fouad
fuvicin
gas-filled radiation-counter tube
gear contact
Gol Gol
Graham Steell accentuated
hamuli
Hartshone bridge
helical mouldboard
Heloderma harridum
impact drive sprinkler
Indonesia Botanical Gardens
inexpressable
inter-macro instruction
iodine water
ironstone
isodactylous
isopiestic level(isobaric surface)
lacus lacrimalis
leap into
liaison ammunition
louisiade archipelago
lower sleeve
lymphographic
manual card
maximum type
miejour
minke whales
mock eightlock
mud stone
N-dimethyItryptamine
national requirements
nephropyosis
olive-dark
oscillating reaction
paleocarpology
permanent steel bulkhead
phosphorus tricyanide
pillarize
pre-cation
prime focus cell
Psiolnemateae
Psoropoidea
Pulvinaria camellicola
purchasing power parity doctrine
pylethrombophlebitis
qatari monetary units
R.D.A.
rabbath ammon (amman)
radiation burner
Rear-Admiral
red Bordeaux
regularities
rianter
school-home
sensitized reaction
small gain theorem
sodiumthiosulfate
son me
speed without load
Sporoxeia
stash houses
superthreshold neutron interrogationtechnique
synchronous 7-unit system
Tamluk
tarsorrhaphy
thalamic paraventricular nucleus
think no small bear of oneself
timber groin
to exceed
total insertion loss
two-way bit
xiphoidian
zearalenols