时间:2019-01-08 作者:英语课 分类:Scientific American(十一)月


英语课

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.


 


Why bother with sex? It’s a question that’s bugged 1 biologists since they first noticed that some critters do it and some don’t. The answer they’ve come up with is that sex generates genetic 2 diversity, which could allow a species to better adapt to changing environments. That’s because sex mixes together the genes 3 from mom and dad. And, like shuffling 4 a deck of cards and dealing 5 new hands, sometimes the kids will get a better combination of genes than their parents had.


So how do species that reproduce by cloning weather change? It turns out not all clones are alike. Scientists from Melbourne were studying a kind of mite 6 that reproduces asexually. In the process, sometimes rare mutations occur, so a clone might be a little different from its parent, and from the rest of the population.


What the scientists found is that sometimes these rare mutants are favored by natural selection. Maybe they’re a little better at hiding from predators 7. So they leave behind more offspring, and eventually come to dominate the population. When circumstances change, another rare mutant might gain favor, results that appear in the current issue of the Proceedings 8 of the National Academy of Sciences. So sex isn’t necessary, as long as you’re willing to back somebody different when it’s time for a change.


 


Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.


 



vt.在…装窃听器(bug的过去式与过去分词形式)
  • The police have bugged his office. 警察在他的办公室装了窃听器。 来自《简明英汉词典》
  • He had bugged off before I had a chance to get a word in. 我还没来得及讲话,他已经走了。 来自《简明英汉词典》
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.基因( gene的名词复数 )
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
n.经商方法,待人态度
  • This store has an excellent reputation for fair dealing.该商店因买卖公道而享有极高的声誉。
  • His fair dealing earned our confidence.他的诚实的行为获得我们的信任。
n.极小的东西;小铜币
  • The poor mite was so ill.可怜的孩子病得这么重。
  • He is a mite taller than I.他比我高一点点。
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面)
  • birds and their earthbound predators 鸟和地面上捕食它们的动物
  • The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
n.进程,过程,议程;诉讼(程序);公报
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • to initiate legal proceedings against sb 对某人提起诉讼
标签: SSS mutation
学英语单词
75
ah-huh
Angled bracket
anticipated transient without scarm
botryblastoconidium
break earth
brush lifting device
buffer stop
butt splice
cacophobia
cancerates
cataplexy
character topology
childhelp
closed convex function
connected digraph
conveyor trip switch
creatural
cross cultural training
cruisegoers
cytherura chanilua
demucosatio intestini
descrived
dew water
dispute to arbitration
docking bracket
double volcano
driving toothed gear
effisax
even mass
exposure of internal abdominal ring
factiousness
fixed-price lump-sum contract
Foot's staining methods
frequency hysteresis
functional generator
funny games
Great Compendium of Acupuncture and Moxibustion
ground drill
half-line block
hot plate tempering
houdon
hours underway
hydrodynamic profile
i-risen
infrared beacon
ink-cap fungi
joint electronics type designation system (jetds)
knowledge inference
knuckleballer
kyllinga monocephala rottb.
lamar
lamination percentage by volume
market-indexes
Mataojo
mesitylene lactone
microorganella
more important
Mount Holyoke College
Mujahidin-e Khalq Organization
network user address
nobilis
observed measure
oocyt
organic element
pally
parallel strand roving
party-trick
peak potential
period of pitching
photothermoplastic
pinky sworn
polygram casting
pork butchers
pressure converter
prologo
resonance-antiresonance method
reverse braking
ribauds
Rio Grande do Norte
road marker
robinov
rose family
salvage cutting
sandbox
sanjays
special memory
St Leonards
Steno, Nicolaus
Steyning
surface servo system
switched-off
transmission direction
trenchworks
undeveloped property
unregulatable
uptake of water by plant
water eryngo
Zincorhodochrosite
zip-ties
zyxin