威斯康辛冰期

But most significant of all, the jaguar has a tell-tale trademark. Instead of going for the neck or snout like most cats do, it kills with a crushing bite through the skull into the brain. This makes the jaguar prime suspect in this case. Even the gl

发表于:2018-12-03 / 阅读(47) / 评论(0) 分类 探索与发现2012年

These holes are the unmistakable hallmark of a violent death. Their shape suggest they were made by the teeth of a big cat, but which one? Today theres only one large cat in the region, the Florida panther. Though similar to the cougar at the western

发表于:2018-12-03 / 阅读(57) / 评论(0) 分类 探索与发现2012年

But how did one man and a spear produce the huge force behind this blow? The answer lies with small bits of ivory like this. They were once part of an atlatl, or spear thrower. An atlatl acts as a sort of catapult, magnifying the strength of a hunter

发表于:2018-12-03 / 阅读(63) / 评论(0) 分类 探索与发现2012年

At first sight, manatees might look like seals or dolphins. But in fact, some of their closest relatives live on land. These toenails are the giveaway, remarkably similar to those of elephants. 13,000 years ago, two other members of the elephant fami

发表于:2018-12-03 / 阅读(60) / 评论(0) 分类 探索与发现2012年

By piecing together the evidence these creatures left behind, we can build a picture of this sub-tropical corner of the continent as it was 13,000 years ago. While most of North America was still in the grip of the Big Freeze, Florida was an ice age

发表于:2018-12-03 / 阅读(67) / 评论(0) 分类 探索与发现2012年

This is Florida, a taste of the tropical, one of the world's most popular holiday destinations. Here mankind's unquenchable desire to explore and colonise reaches astronomical proportions. Eight, seven, six, five, four, three, two, one. Ignition. Lif

发表于:2018-12-03 / 阅读(48) / 评论(0) 分类 探索与发现2012年

This creates steam in oasis and a profusion of life. Today, these warm springs are a refuge for one of Florida's most tropical inhabitants. The West Indian Manatee wasn't present during the last ice age, but returned here as the waters warmed up. Eve

发表于:2018-12-03 / 阅读(65) / 评论(0) 分类 探索与发现2012年

But the glyptodont wasn't a reptile. So what was it? There is a relative of the glyptodont thats still alive today. It's the armadillo and it's a mammal, the only mammal with this kind of armor in the whole of North America. It may give us some idea

发表于:2018-12-03 / 阅读(68) / 评论(0) 分类 探索与发现2012年

This triggered other dramatic changes. As sea levels dropped, so did the inland water tables. Florida's fresh water drained away through the porous limestone rock. Pools dried up and springs diminished. Florida was on the brink of drought. And animal

发表于:2018-12-27 / 阅读(51) / 评论(0) 分类 探索与发现2013年

Could it be that drastic water shortage was the reason for the mastodons' epic migrations? Another big piece of this puzzle lies far out to sea. This is the ocean floor. But this isn't rock sprouting out at the bottom. It's wood. It's the remains of

发表于:2018-12-27 / 阅读(46) / 评论(0) 分类 探索与发现2013年

But despite their name, the mighty Everglades did not exist during the ice age. So what did pre-historic Florida look like? There is one place in northern Florida that has revealed more ice age secrets than almost anywhere else, the dark slow-moving

发表于:2018-12-27 / 阅读(48) / 评论(0) 分类 探索与发现2013年

The cold climate conifer forests of the north displaced broadleaved woodlands. Plants and animals were gradually pushed south to find a warmer climate. Florida became a refuge from the cold. Down here is where the Ice Age north met the subtropical so

发表于:2018-12-27 / 阅读(46) / 评论(0) 分类 探索与发现2013年

Like a science fiction time traveler, an arctic plant of the late Pleistocene age, over thirty one thousand years old, is growing again after a long frozen sleep. 犹如科幻小说里的时间旅行者,一种曾存活在更新世晚期的极地植物

发表于:2018-12-28 / 阅读(64) / 评论(0) 分类 初学者听力文摘精选

During the last ice age, rapid swings in temperature occurred within decades or less, meaning populations of organisms had to adjust quickly to new environments or face extinction. 在最后一个冰河世纪中,温度在数十年甚至更短的时间

发表于:2018-12-28 / 阅读(45) / 评论(0) 分类 初学者听力文摘精选

By Alan Silverman Hollywood 02 April 2006 It's back to prehistoric times for a sequel to the 2002 computer-animated family film that featured a grumpy mammoth and his traveling companions: a quick-wit

发表于:2019-01-08 / 阅读(114) / 评论(0) 分类 2006年VOA标准英语(四月)

Global Warming Could Delay Next Ice Age The next ice age could be delayed by tens of thousands of years due to excessive amounts of heat-trapping carbon dioxide in the atmosphere, which disrupts Earths natural cycle of warming and cooling, according

发表于:2019-01-13 / 阅读(77) / 评论(0) 分类 VOA标准英语2012年(一月)

Ice Age Melt Offers Future Climate Clues University of Wisconsin geologist Anders Carlson studies ice sheet melt from land and ocean sediment cores. His study describes what prehistoric Earth was like in North America and Northern Europe some 140,000

发表于:2019-01-13 / 阅读(58) / 评论(0) 分类 VOA标准英语2012年(八月)

Greenhouse Gas Speeded Ice Age Melting A new study in the Journal Nature provides compelling evidence that carbon dioxide was a major driver of climate change at the end of the last Ice Age. That correlation supports the prevailing scientific view th

发表于:2019-01-13 / 阅读(55) / 评论(0) 分类 VOA标准英语2012年(四月)

In the heat of the day, hunters can afford to slow down and rest in the shade. Its one of the advantages of a high-protein diet. Llamas originated here in North America are the regular visitors to the spring. The strange-looking tapir is common too.

发表于:2019-01-23 / 阅读(63) / 评论(0) 分类 探索与发现2013年

Though very powerful, shes not a sprinter and she needs to get close to her prey before she strikes. This time shes run too soon and its a fruitless chase. Then her attention is diverted to a slower-moving target, slow but not defenseless. She backs

发表于:2019-01-23 / 阅读(57) / 评论(0) 分类 探索与发现2013年
学英语单词
abdal
ambisexualities
antihumanglobulin consumption test
aqueductus Sylvii
Archimedes law
aubry
back splicing
balmified
base line stabilizer
be confounded with
be lovely
bio-hazards
biodiagnostic
black leopard
bottom drop car
broken terrain
business district
Candle Lake
chopper-stabilized amplifier
cimbric
common wheat
curated
cypraea walkeri
decigramme
Deer Creek
dicksonii
diesel engine exhaust
diligent
discussion
doters
dry piston compressor
electronic leather area measuring machine
endomyocardial biopsy
endosexine
etozoline
food-stuff industry
guild
harden off
heavy spar
Helsingor
heterogeneous x-ray
hydraulic transporting device
hydroxypropylcellulose
in litteris
ineligible bills
Kazakstan, Kazakhstan
Khinganskiy Zapovednik
kyking
larson-juhl
lattice unit
Loi, Nam
lon-gitudinal survey
macoma baltica
marketing margin
meadow ferns
melodiographs
membranotropic
merchandise legal weight
mortar factor
myo
new institutional economics
nonemployer
nuptialling
off-Broadway
operating diskette
orderin'
orientational coring
outer-arc ridge
Pattison
personal communications network
ploughshare
pressure cook
program generation
prototype liquid
pseudohydrophobia
radialerror
rained cats and dogs
Richard Strauss
selectrifiner
self fluxing sintered ore
servomechanism tester
signal latency
signing bonus
smuttiest
sprinkler nominal working pressure
straight people
TEM wave
the joke of the town
theanthropist
themyl
theory of numbers
thermoelectrical colorimeter
triorthogonal
uneven bottoming
us toll
visnomy
Vucine
Web site management
webge clamp
whorled milkweeds
xanthated
yezidi dance (syria)