万物简史 第478期:生命在前进(20)

Many of the Burgess specimens have now been assigned to living phyla just where Walcott put them in the first place. 许多布尔吉斯标本现在已经归到活着的动物的门里就是沃尔科特最初放置它们的地方。 Hallucigenia and s

SSS 2011-03-29

This is Scientific Americans 60-Second Science. Im Steve Mirsky. Got a minute? To keep your car purring, you have to change the oil. Such maintenance produces eight billion gallons of used motor oil annually. Some waste oil does get re-refined to pro

英语听力：2012-01-20 从南极到北极 From Pole To Pole—2

The penguins stay when all other creatures have fled because each guards a treasurea single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach. There is no food and no water for them. And they will not see the sun

英文书摘精选 有趣的事实,短嘴鳄可以再长牙齿

Fun Fact: Alligators Can Regrow Teeth 有趣的事实：短嘴鳄可以再长牙齿 Fun fact about alligators: they can regrow any of their eighty teeth up to fifty times. Which is pretty impressive, especially compared to us relatively dentally chal

英语听力文摘 English Digest 600、科学家如何预测火山喷发？

its time again for the A Moment of Science mailbag. A listener writes: Dear A Moment of Science, Ive always been fascinated by volcanoes. So I was wondering: How well can scientists predict when and where a volcano will erupt? Intersting question. Th

SSS 2008-04-17

This is Scientific American's 60-Second Science. I am Steve Mirsky.Got a minute? Talk about your vicious cycles. A new study finds that belly fat could be making you hungrier. Which would lead to more belly fat. The research was performed at the Univ

SSS 2009-11-13

Algae seem harmless enough. These precursors to plants thrive throughout the world's waters. But these single-celled plants have global consequences. We can thank them for oxygen in the atmosphere, oil in the lithosphere as well as dead zones in the

VOA标准英语2012--Azaz Residents Pick Up After Aerial Bombings

Azaz Residents Pick Up After Aerial Bombings The residents of Azaz clean up and mourn after Wednesday's deadly bombing by Syrian government warplanes. Azaz had been peaceful in recent months, although forces of the rebel Free Syrian Army have had to

英语听力：2012-01-22 从南极到北极 From Pole To Pole—3

But they are hungry and eager to reach their mother whos delayed feeding them on this special day. Now she lures them with the promise of milk, the only food the cubs have known since they were born, deaf and blind beneath the snow some two months ag

英语听力：2012-01-25 从南极到北极 From Pole To Pole—4

Day 10. And the mother has let her cubs a mile from the den. Its time to put them to the test. Theyve grown enormously in confidence, but they dont have their mothers sense of urgency. At last it seems that they are ready for their journey. And they

英语听力：2012-01-29 从南极到北极 From Pole To Pole—6

Midsummer on the tundra and the sun does not set. At these altitudes, the suns rays are glancing and not enough of their energy reaches the ground to enable trees to grow. Youll need to travel five hundred miles south from here before that is possibl

英语听力：2012-02-01 从南极到北极 From Pole To Pole—7

As we travel south, so the suns influence grows stronger. And at 50 degrees of latitude, a radical transformation begins. Summers here are long enough for broadleaf trees to replace conifers. Broadleaves are easier to eat and digest, so now animals c

英语听力：2012-02-05 从南极到北极 From Pole To Pole—9

The advance of the seasons brings constant change. As the suns influence diminishes in the north, so the deciduous forests of America begin to shut down, losing their leaves in preparation for the dark, cold months ahead. One season hands over to ano

英语听力：2012-02-08 从南极到北极 From Pole To Pole—10

The character of the forest changes as we descend, becoming ever darker and damper, favoring different kinds of animals and plants. Less than two percent of the sunlight reaches the floor. But even here there is extraordinary variety. In the Great Is

英语听力：2012-02-15 从南极到北极 From Pole To Pole—13

The sun beating down on tropical waters powers the weather systems of the globe. Moisture evaporates from the warming ocean and rises to create great storms. The winds generated out at sea sweep inland across the continents. As they travel across the

英语听力：2012-02-03 从南极到北极 From Pole To Pole—8

Deer are frequent casulties of the harsh winter. And these leopards are not above scavenging from a corpse. African leopards could never survive here. But the Russian cats have thick fur to shied them from the cold. There are only 40 Amur leopards le

英语听力：2012-02-24 从南极到北极 From Pole To Pole—17

Their secret is teamwork. Impala are their favourite prey. They start to hunt and the pack splits up. An aerial viewpoint gives a new insight into their strategy. As the dogs approach their prey, they peel off to take up separate positions around the

英语听力：2012-02-26 从南极到北极 From Pole To Pole—18

The dogs know their prey must come out or drown. Now its a waiting game. The rest of the pack are calling. Theyve made a kill in the forest and this is an invitation to join in the meal. The impala is in luck. A pack this size kills once a day and ev

英语听力：2012-02-17 从南极到北极 From Pole To Pole—14

All across southern Africa, all animals are journeying for the same reason. Buffalo join the great track. Nowhere else on Earth are so many animals on the move for the same urgent purpose. They are all heading for the swamps of the Okavango, a vast i

Researchers make sperm from stem cell in dish

WASHINGTON, Aug. 4 (Xinhua) -- Researchers have found a way to turn mouse embryonic stem cells into sperm and this finding opens up new avenues for infertility research and treatment, according to astudy published Thursday in the online edition of jo