A recent study of ancient and modern elephants has come up with the unexpected conclusion that the African elephant is divided into two distinct species.
The discovery was made by researchers at York and Harvard universities when they were examining the genetic relationship between the ancient woolly mammoth and mastodon to modern elephants — the Asian elephant, African forest elephant and African savanna elephant.
Once they obtained DNA sequences from two fossils, mammoths and mastodons the team compared them with DNA from modern elephants. They found to their amazement that modern forest and savanna elephants are as distinct from each other as Asian elephants and mammoths.
The scientists used detailed genetic analysis to prove that the African savanna elephants and the African forest elephants have been distinct species for several million years. The divergence of the two species took place around the time of the divergence of Asian elephants and woolly mammoths. This result amazed all the scientists.
There has long been debate in the scientific community that the two might be separate species but this is the most convincing scientific evidence so far that they are indeed different species.
Previously, many naturalists believed that African savanna elephants and African forest elephants were two populations of the same species despite the elephants’ significant size differences. The savanna elephant has an average shoulder height of 3.5metres while the forest elephant has an average shoulder height of 2.5metres. The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant. But the fact that they look so different does not necessarily mean they are different species. However, the proof lay in the analysis of the DNA.
Alfred Roca, assistant professor in the department of Animal Sciences at the University of Minois, said, “We now have to treat the forest and savanna elephants as two different units for conservation purpose. Since 1950 all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinct animals, the forest elephant should become a bigger priority for conservation purpose.”
1. One of the fossils studied by the researchers is that of ________.A.the Asian elephant | B.the forest elephant |
C.the savanna elephant | D.the mastodon elephant |
A.evolution | B.exhibition | C.separation | D.examination |
A.DNA | B.height | C.weight | D.population |
A.The conservation of African elephants. |
B.The purpose of studying African elephants |
C.The way to divide African elephants into two units |
D.The reason for the distinction of African elephants |
A.Naturalist’s Belief about Elephants. | B.Amazing Experiment about Elephants |
C.An Unexpected Finding about Elephants | D.A Long scientific Debate about Elephants |
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【推荐1】Bald eagles are a breathtaking sight, no matter where you see them. Bald eagles are making headlines again, as proven by NPR’s story about the birds’ amazing recovery in Chesapeake Bay.
“Forty years ago, we probably would not have seen a single bald eagle here,” says Bryan Watts, a conservation biologist. This is a familiar story across a nation where pollution and pesticides(杀虫剂) nearly wiped out the species in the United States. The bald eagle was on the endangered species list for decades, and considerable recovery efforts were put into place to bring the national symbol back.
It was delisted in 2007, and stories of its recovery have continued to be a source of celebration from Glenwood, Iowa to Chicago to Sandy Island Eagle Sanctuary in Missouri. The fascination with watching this species come back with vigor(活力) has been equally as wonderful as witnessing the recovery itself. Some efforts to help endangered species recover can be controversial, but the recovery of the bald eagle has been a story everyone can get behind. A bald eagle nest in Decorah, Iowa brings in millions of viewers every season as the parents hatch their chicks. It’s not often a livestream angled on a bird’s nest gets that kind of viewership!
The conservation effort has not been easy and in some areas, such as the Channel Islands off the California coast, it is really tough to carry out. Bald eagles once called these islands home but disappeared with the emergence of the pesticide DDT. In addition, humans changed the ecosystem there by introducing invasive species. Restoration efforts have included removing the alien species and helping native species. A program for reintroducing bald eagles starting in 2002 has been a success, with 2010 seeing a record-setting 15 wild chicks hatched.
At present, while there are many dangers that still face the bald eagle, the incredibly successful recovery over the last several decades is a conservation story to champion - and one to feed hope for other endangered species whose recovery is still underway.
1. What were bald eagles faced with four decades ago?A.They were at risk of extinction. |
B.They were nearly killed by pesticides. |
C.They were facing hunted by human beings. |
D.They were saved through some recovery efforts. |
A.Confidential. | B.Casual. | C.Effective. | D.Conservative. |
A.The concepts and difficulties. |
B.The challenges and measures. |
C.The strategies and promises. |
D.The methods and achievements. |
A.Not all hopes were lost in protecting nature. |
B.Ups and downs are common in the ecosystem. |
C.There is still a long way to protect wild animals. |
D.Dangers in the wild advance the growth of wildlife. |
【推荐2】The air is thin and we have to rest several times on the shore hike from camp. To our left, snow-covered mountains disappear into clouds that seem almost close enough to touch. On the plain in front of us, we can just make out a herd of graceful animals. This is why we stay here.
Tibetan antelopes live mainly on the plains of Tibet. Watching them move slowly across the green grass, I'm struck by their beauty. I'm also reminded of the danger they are in. They are being hunted illegally for their valuable fur.
My guide is Zhaxi, a villager from Changtang. He works at the Changtang National Nature Reserve. The reserve is a safe place for the animals and plants of northwestern Tibet. To Zhaxi, protecting the wildlife is a way of life. “We're not trying to save the animals,” he says. “Actually, we're trying to save ourselves.”
In the 1980s and 1990s the population of Tibetan antelopes dropped by more than 50 percent. Hunters were shooting antelopes to make money. Their living places were becoming smaller as new roads and railways were built.
In order to save Tibetan antelopes, the Chinese government placed them under national protection. Zhaxi and volunteers watched over the antelopes day and night to keep them safe from attacks. Bridges and gates were added to let the antelopes move easily and keep them safe from cars and trains.
The measures were effective. The antelope population has recovered and in June 2015, the Tibetan antelope was removed from the endangered species list. The government, however, does not intend to stop the protection program since the threat to the Tibetan antelope has not yet disappeared. Only when we learn to exist in harmony with nature can we stop being a threat to wildlife and to our planet.
1. What can we learn from Zhaxi's words in paragraph 3?A.Protecting the animals can make money. | B.Protecting the animals is protecting ourselves. |
C.He is not fond of protecting the animals. | D.The reserve is only safe for wild animals. |
A.Why hunters hunt Tibetan antelopes. | B.Why antelopes' living places changed. |
C.Why antelopes' number dropped greatly. | D.Why the 1980s and the 1990s are unusual. |
A.Deleted. | B.Changed. | C.Migrated. | D.Recognized. |
A.They will be over-populated. |
B.They will be a threat to man and other wildlife. |
C.They will be on the endangered species list again. |
D.They will be in harmony with nature and humans. |
【推荐3】In nature, smaller animals often “take a ride” on larger ones to save energy on long-distance movements. In paper published in the journal Current Biology, researchers show how fine Caenorhabditis worms can use electric fields to “jump” across Petri plates or onto insects, allowing them to go through the air and attach themselves, for example, onto naturally charged bumblebees (大黄蜂).
“Pollinators(传粉昆虫), such as insects and hummingbirds, are known to be electrically charged, and it is believed that pollen (花粉) is attracted by the electric field formed by the pollinator and the plant,” says Takuma Sugi, a co-senior author on the study. “However, it was not completely clear whether electric fields are used for communications between different land animals.”
The researchers first began studying this project when they noticed that the worms they developed often ended up on the lids of Petri dishes. When the team attached a camera to observe this behaviour, they found that it was not just because worms were climbing up the walls of the dish. Instead, they were jumping from the floor of the plate to the top.
Next, the researchers rubbed flower pollen on a bumblebee. Once close to these bees, worms stood on their tails, then jumped aboard. Some worms even piled on top of each other and jumped in a single post, moving 80 worms at once across the gap.
“Worms stand on their tail to make it easier for themselves to attach to other passing objects,” Sugi says. “In a post, one worm lifts more worms, and this worm takes off to move across the electric field while carrying all the post worms.
Researchers observed jumping in other worm species closely related to C. elegans, and they noted that mutants (突变体) who are unable to sense electric fields jump less than their normal counterparts. However, more work is needed to determine exactly what genes join in making these jumps and whether other microorganisms like bacteria can use electricity to jump as well.
1. Which is certain according to the research?A.Bacteria use electricity to jump. |
B.Smaller animals are often free riders. |
C.Electric fields are used for land animals. |
D.Pollen genes lead to making these jumps. |
A.To form stronger posts. | B.To increase the surface energy. |
C.To get electricity and jump more. | D.To show a natural electric charge. |
A.They are electrically charged. |
B.They attach themselves to the walls. |
C.They are equipped with team spirits. |
D.They communicate with each other with tails. |
A.Worms Use Electricity to Jump |
B.Worms Takes off Carrying Others |
C.Pollen Helps Worms Survive Longer |
D.Smaller Animals Ride onto Bigger Ones |
【推荐1】Why do we find ugly animals so appealing? And what makes odd-looking creatures so cute?
Evolution (进化) plays a role. According to Austrian zoologist Konrad Lorenz, human attraction to childish features, such as big eyes, large heads and soft bodies, is an evolutionary adaptation that helps ensure that adults care for their young, guaranteeing the survival of their species. Odd-looking animals such as blobfish, pugs, and bulldogs all share these childish qualities that initiate an affectionate response among humans. And these childish characteristics increase a person’s “protective behavior, attention and willingness to care” for the individual and reduce the “likelihood of attacks towards a child”, says Marta Borgi, a researcher.
Ugly animals often have other value—some, like the blobfish or the naked mole rat, live in extreme environments that they have adapted to in remarkable ways. Scientists are keen to study these animals to understand whether their biology might provide fresh insights that could lead to treatments for human health conditions such as cancer, heart disease and other deadly diseases.
Our fascination with ugly-cute animals can also be traced back to culturally-based causes. “The ugly-cute thing is very fashionable,” says Rowena Packer, a lecturer of animal behavior. “This is partly driven by social media, with many influential people showing off pet pugs and French bulldogs on the Internet,” she says.
But there are some serious welfare concerns around this trend. Vets are urging people not to choose a flat-faced dog, because they suffer from serious health problems. Pugs and French bulldogs which have been selectively produced experience breathing difficulties, repeated skin infections and eye diseases.
We may want to rethink our love for “ugly-cute” animals because of their silly features like protruding (鼓出的) eyes and wrinkly faces.
1. Why do people like ugly animals according to Konrad Lorenz?A.People appriciate their efforts to survive. | B.People appreciate their super adaptability. |
C.People are attracted by their childish looks. | D.People are fond of their fast response speed. |
A.What media are changing people. | B.How public practices influence people. |
C.Whether social media is worth believing. | D.Why celebrities show off their pet animals. |
A.Opposed. | B.Supportive. | C.Indifferent. | D.Cautious. |
A.By quoting different researchers’ findings. | B.By showing some examples of keeping pets. |
C.By observing people’s behavior towards animals. | D.By referring to authoritative evolutionary theory. |
【推荐2】People use laughter to connect and bond with others. It’s how we tell friends that their jokes are funny.
What about other animals?
When compared to human laughs, animal laughter sounds very different, especially between different animals. While vervet monkeys (长尾猴) make a purring sound in playing, squirrel monkeys produce a soft peeping sound.
Most primates make sounds of “he he” and smack their lips when playing. This might help explain where human laughter comes from.
A.This is an issue that has not been settled so far. |
B.It’s also how kids show that they are having fun. |
C.For many animals, laughter is a way to start play. |
D.Bottlenose dolphins whistle while they swim and jump together. |
E.Many animals laugh so that their play partners know they are having fun. |
F.Experts believe that humans may have started off laughing like some monkeys do. |
G.This is just what the scientists from the University of California tried to find out recently. |
【推荐3】Believe it or not, there are many strange things banned around the world.
Black cars—Turkmenistan
Trying to buy a new car in the central Asian country of Turkmenistan can be a tricky business due to numerous restrictions issued by President Gurbanguly Berdimuhamedov. Batir Turken, who is from Turkmenistan but lives in Dubal, explained, “For the country with 60℃ in summer, it is really strange and stupid—cars with black colors are banned, and dirty cars are not allowed to drive in the city.”
He added, “Cars which are older than five years are banned, cars with a right-hand drive are banned, sports cars and two-door cars are banned, and cars with tinted(有色的) windows are banned.”
Vacuum cleaners(真空吸尘器)Victoria—Australia
No one likes a noisy neighbor, but the state of Victoria in Australia has introduced a set of rules about at what point during the day you can make noise including when you can vacuum.
Sumit Gupta, Mumbai, India, said,“In Melbourne, Australia, vacuuming your house between 10 pm and 7am during weekdays and 10 pm and 9 am during the weekends is against the law.”
Chewing gum—Singapore
Singapore prohibits the sale and import of chewing gum,which makes it impossible for locals to get their hands on gum. However, exceptions are made for people who have medical conditions and need to chew gum. The ban began in 1992 and is still in effect.
Running out of fuel—Germany
People are not allowed to let their cars run out of fuel if they are driving on the autobahn(高速公路) in Germany. What complicates matters is that a person can’t walk along the highway to get some gas, as walking on the autobahn is also prohibited by law.
Changing bulb—Victoria, Australia
In Victoria, one of the most populous states in Australia, changing a light bulb is illegal unless you are a licensed electrician. People who disobey this law could receive a fine of up to AU$10(£5.5).
1. Which kinds of cars are Not banned in Turkmenistan?A.cars used for six years | B.cars with a left-hand drive |
C.cars with colored windows | D.sports cars |
A.Running out of fuel is forbidden in this country. |
B.Whoever walks on the autobahn is against the law. |
C.Dirty cars are not allowed to drive in the city. |
D.The ban of running out of fuel is out of effect now. |
A.Batir Turken considers it an absurd idea to ban black cars in Turkmenistan. |
B.A person who is ill and needs to chew gum will be fined for chewing gum. |
C.You can change a light bulb as long as you handle with care. |
D.People vacuuming houses at midnight in Melbourne will be fined AU$10. |
【推荐1】Some people say that the best way to reduce the size of your waist is to do stomach exercise. Many people believe that when specific muscles are exercised,the fatty tissues(组织)in the immediate area are burned up. The truth is that exercise burns fat from all over the body and not from one specific area. Of course,if you reduce the fat throughout your body,you will certainly see results around your waist,too.
Some people believe that you need to exercise twice a week in order to keep a sufficient level of physical fitness. However,studies directed by American scientists show that unexercised muscles lose their strength very quickly. Within 48 to 72 hours,you must use the muscles again to reestablish(重建)the good physical effects. And what does that mean to you?American scientists concluded that while daily exercise is most helpful,exercising every other day or three days a week will keep a sufficient level of physical fitness.
Is it true that you burn more calories running one mile than walking the same distance?The answer is no. The truth is that you use the same amount of energy whether you walk or run the mile,since in both cases you are moving the same weight the same distance. The speed does not matter. Of course,if you run rather than walk for 30 minutes,you will cover more distance,and therefore,burn more calories.
If your breathing doesn't return to normal within 5 minutes after you finish exercising,you have exercised too much. Five minutes or so after exercising,your breathing should be normal,your heart shouldn't be beating loudly,and you shouldn't be tired.
1. If you want to reduce the fat around your waist,you should________.A.do stomach exercise |
B.exercise the waist |
C.exercise all the muscles of your body |
D.run fast for 30 minutes |
A.we only need to exercise twice a week |
B.we should exercise three times a week |
C.muscles lose their strength after 48 hours |
D.we should exercise every other day,or three days a week |
A.your breathing will take longer than 5 minutes to return to normal after you finish exercising |
B.your breathing will return to normal within 5 minutes after finishing exercising |
C.your heart will not be beating loudly |
D.you will be too tired to move |
A.it is better to do more running than walking |
B.the more exercise you do,the healthier you will be |
C.the unexercised muscles must be used again within 48 to 72 hours |
D.in order to lose weight,you have to run fast |
【推荐2】Do you know the term "tweenager"? It's a slang word being used in the UK to describe children 10-13 years old. They are between junior and the teenage years. Why are they suddenly referred to in this way?
Tweenagers now have more money, freedom and influence upon their parents than they've ever had before. More and more companies are creating products and services for tweenagers. You can get everything from branded lunchboxes and mobile phone covers, to monthly fan magazines and clothing-it's all about sales.
Most children in the UK today get more pocket money than kids did a decade ago. It is because parents are having fewer children on average than in the past. In addition, the divorce rate in the UK is continually rising and parents spend less time with their children than they used to. So, many parents try to compensate(补偿) by buying presents for them.
And do tweenagers have more freedom? Well, UK children today are very familiar with media and computer. Many have a television, if not a computer, in their bedrooms. They have access to much more information about the world.
They may have experienced a lot in life as well, since 24% of UK kids live in single-parent families. People now say that "Kids are getting older younger". With such sophistication (世故) at such a young age, they are much more fashion conscious and concerned about their image.
In a world of TV programs that promise overnight success and fame at a young age, some people think it's extremely important to look fashionable. Surely none of the above is a good thing, is it? Can it really be healthy for us to encourage kids to be like adults at such a young age? Are we stealing childhoods in return for profit?
The UK government is certainly concerned, and for that reason has strict laws preventing companies from marketing their products and services at children. So, is there a happy ending to this story?
Companies have just worked out that the older tweenage audience is now looking for something darker and more rebellious. As a result, films such as Twilight are being produced for this older tweenage audience.
1. More and more companies pay attention to the tweenagers because________________.A.tweenagers have a growing interest in lunchboxes and mobile phones |
B.parents are more likely to spend money for their kids than before |
C.kids receive less pocket money now but have more freedom |
D.every kid has a computer or a TV in their bedroom |
A.Kids have a great influence on the market. |
B.The products for the kids are of better quality. |
C.Kids are more fashionable than other earlier generations. |
D.Kids like to buy magazines and clothing most. |
A.Children exercise too little to physically healthy. |
B.Children look older than they actually should be. |
C.Children know more than earlier generations of youngsters knew. |
D.Children have more freedom and appear more mature than previous generations. |
A.The companies make use of tweenagers to make money. |
B.Young tweenagers are having a positive influence on adult. |
C.The market is changing to meet the demand of kids. |
D.Darker and more rebellious movies are popular with kids. |
【推荐3】Like a tired marriage, the relationship between libraries and publishers has long been dull. E-books, however, are causing heartache. Libraries know they need digital wares, but many publishers are too cautious about piracy(盗版) and lost sales to co-operate. Among the big six, only Random House and Harper Collins license e-books with most libraries.
Publishers are wise to be nervous. Owners of e-readers(电子阅读器) are exactly the customers they need: book-lovers with money. If these people switch to borrowing e-books instead of buying them, what then? Electronic borrowing is awfully convenient. Unlike printed books, which must be checked out and returned to a physical library miles from where you live, book files can be downloaded at home. The files disappear from the device when they are due.
E-lending is not simple, however. There are lots of different and often incompatible(不兼容的)e-book formats devices and licenses. Most libraries use a company called OverDrive, which secures rights from publishers and provides e-books and audio files in every format. Yet publishers and libraries are worried by OverDrive’s global market dominance the company can control fees and conditions. Publishers were annoyed when OverDrive cooperated with Amazon, the world’s biggest online bookseller, last year. Owners of Amazon’s Kindle e-reader who want to borrow e-books from libraries are now redirected to Amazon’s website, where they must use their Amazon account to secure a loan.
According to Pew, an opinion researcher library users are a perfect for market for Amazon. Late last year Amazon introduced its Kindle Owners’ Lending Library, which lets its best customers borrow free one of thousands of popular books each month.
Library supporters argue that book borrowers are also book buyers and that libraries are vital spaces for readers to discover new work. Many were cheered by a recent Pew survey, which found that more than half of Americans with library cards say they prefer to buy their e-books.
So publishers keep adjusting their lending arrangements in search of the right balance.
Random House raised its licensing prices earlier this year, and Harper Collins limits libraries to lending its titles 26 times.
1. It can be inferred from paragraph 1 that __________.A.libraries and publishers face the same problem of e-books’ piracy |
B.libraries are eager to keep strong relationship with publishers |
C.most publishers are hesitant to cooperate with libraries |
D.several big publishers have sold e-books to libraries |
A.Book sales may drop sharply because of convenient electronic borrowing. |
B.There are lots of different and incompatible e-book formats available |
C.There is no time limit for the book files downloaded on the device. |
D.E-books must be checked out and returned to libraries regularly. |
A.e-books can be lent at libraries as many times as you like |
B.OverDrive distributes e-books and audio files to publishers |
C.over half of Americans are borrowing e-books from libraries |
D.Amazon is adopting measures to win more customers |
A.The Hopeful Future of Publishing Business |
B.The Uncertain Economics of Lending E-books |
C.The Dull Relationship between Libraries and Publishers |
D.The Close Cooperation between Over and Amazon |