Endangered polar bears are breeding with grizzly bears, creating “pizzly” bears, which is being driven by climate change, scientists say.
As the world warms and Arctic sea ice thins, starving polar bears are being forced ever further south, where they meet grizzlies, whose ranges are expanding northwards. And with that growing contact between the two come increasing hybrids (杂交种), “pizzly” bears.
With features that could give the hybrids an advantage in warming northern habitats, some scientists guess that they could be here to stay. “Usually, the hybrids,“pizzly” bears aren’t better suited to their environments than their parents, but these hybrids are able to search for a wider range of food sources, ” Larisa DeSantis, an associate professor of biological sciences at Vanderbilt University, told Live Science.
The rise of “pizzly” bears appears with polar bears’ decrease: their number is estimated to go down by more than 30% in the next 30 years. This sudden fall is related partly to “pizzly” bears taking up polar bears’ ranges, but also to polar bears’ highly specialized diets.
“Polar bears mainly consumed soft foods even during the Medieval Warm Period, a previous period of rapid warming,” DeSantis said, referring to fat meals such as seals. “Although all of these starving polar bears are trying to find alternative food sources like seabird eggs.” Actually, the calories they gain from these sources do not balance out(抵消) those they burn from searching for them. This could result in a habitat ready for the hybrids to move in and take over, leading to a loss in biodiversity if polar bears are replaced.
“We’re having massive impacts with climate change on species,” DeSantis said. “The polar bear is telling us how bad things are. In some sense, “pizzly” bears could be a sad but necessary compromise(妥协) given current warming trends.”
1. Why do polar bears move further south?| A．To create hybrids. | B．To expand territory. |
| C．To deal with hunger. | D．To contact grizzlies. |
| A．Wider habitats. | B．More food choices. |
| C．Climate preference. | D．Improved breeding ability. |
| A．Polar bears are increasing. | B．Polar bears like soft foods. |
| C．Polar bears hate fat meals such as seals. | D．Climate change can benefit polar bears. |
| A．Polar bears are changing diets for climate change. |
| B．Polar bears have already adjusted to climate change. |
| C．“Pizzly” bears are on the rise because of global warming. |
| D．“Pizzly” bears have replaced polar bears for global warming. |
相似题推荐
【推荐1】How could we possibly think that keeping animals in cages in unnatural environments－mostly for entertainment purposes－is fair and respectful?
Zoo officials say they are concerned about animals. However, most zoos remain “collections” of interesting “things” rather than protective habitats. Zoos teach people that it is acceptable to keep animals bored, lonely, and far from their natural homes.
Zoos claim to educate people and save endangered species, but visitors leave zoos without having learned anything meaningful about the animals’ natural behavior, intelligence, or beauty. Zoos keep animals in small spaces or cages, and most signs only mention the species’ name, diet, and natural range(分布区). The animals’ normal behavior is seldom noticed because zoos don’t usually take care of the animals’ natural needs.
The animals are kept together in small spaces, with no privacy and little opportunity for mental and physical exercise. This results in unusually self-destructive behavior called zoochosis. A worldwide study of zoos found that zoochosis is common among animals kept in small spaces or cages. Another study showed that elephants spend 22 percent of their time making repeated head movements or biting cage bars, and bears spend 30 percent of their time walking back and forth, a sign of unhappiness and pain.
Furthermore, most animals in zoos are not endangered. Captive breeding(圈养繁殖) of endangered big cats, Asian elephants, and other species has not resulted in their being sent back to the wild. Zoos talk a lot about their captive breeding programs because they do not want people to worry about a species dying out. In fact, baby animals also attract a lot of paying customers. Haven’t we seen enough competitions to name baby animals?
Actually, we will save endangered species only if we save their habitats and put an end to the reasons people kill them. Instead of supporting zoos, we should support groups that work to protect animals’ natural habitats.
1. In the state of zoochosis, animals _________.| A．remain in cages | B．behave strangely |
| C．attack other animals | D．enjoy moving around |
| A．Zoos are not worth the public support. |
| B．Zoos fail in their attempt to save animals. |
| C．Zoos should treat animals as human beings. |
| D．Zoos use animals as a means of entertainment. |
| A．pointing out the faults in what zoos do |
| B．using evidence he has collected at zoos |
| C．questioning the way animals are protected |
| D．discussing the advantages of natural habitats |
| A．zoos have to keep animals in small cages |
| B．most animals in zoos are endangered species |
| C．some endangered animals are reproduced in zoos |
| D．it’s acceptable to keep animals away from their habitats |
【推荐2】It only takes one wrong step near a lake in the winter for disaster to happen. Pepper, the dog and his mom found that out the hard way.
The two of them were taking a morning walk in Chicago along Lake Michigan when Pepper, a 7-year-old dog, got free of its rope, slipped on some rocks, and fell onto the ice sheets of the lake. As Pepper tried to climb back up to his human owner, the ice around him broke, and he began floating (漂浮) away!
Since the water was so cold, Pepper should be saved as soon as possible. As Fire Deputy District Chief Jason Lach said, hypothermia (a serious medical condition caused by very low temperature) can start within several minutes. Thankfully, firefighters were already nearby practicing underwater ice dives.
Just 10 minutes later, 40 rescue (救援) workers arrived, along with fire department vehicles and a helicopter. By the time the officials in the helicopter noticed Pepper, he and his ice float were 500 feet out into the lake. Firefighter Chris Iverson dove into the water and swam out to Pepper. Chris calmed the dog down and tied him to a safety sling (吊索). Meanwhile, firefighter Emerson Branch swam out with a rapid deployment craft, which he and Chris used to bring Pepper safely to shore. The rescue only took about 15 minutes. When the firefighters reached dry land with Pepper, they dried him using a towel and played the pass-the-dog to get him back to his human owner.
Caretakers at Veterinary Emergency Group Hospital made sure Pepper was OK. But Jason hopes his rescue will be a lesson for others. “The dog was good, warmed up to its owner, and went on its happy way,” Jason said. “But stay off the ice. It’s never safe, …Step into a hole, and you’re out of sight.”
1. What happened to Pepper one morning?| A．He lost his owner. | B．He was trapped in a lake. |
| C．He got missing suddenly. | D．He was covered by ice sheets. |
| A．The cold water. | B．Poor medical conditions. |
| C．Rescue equipment shortage. | D．The changeable temperature. |
| A．The rescue lasted about an hour. | B．Pepper got to the shore alone. |
| C．The rescue was highly effective. | D．Pepper reacted calmly all the time. |
| A．No going near the ice. | B．No walking dogs by a hole. |
| C．Taking good care of pets. | D．Warming up well before exercise. |
【推荐3】The Whale’s Voyage
Strange as it may seem, modern whales’ ancestors didn’t always live in the water.
The journey whales made from land to water began about 50 million years ago. The dinosaurs had already disappeared.
Some of these ancient mammals began to wander along muddy shores and explore the water. They were probably searching for food.
Fossils provided clues to the whales’ past. The secret was locked in the skulls of their four-legged ancestors. Scientists found features similar to those of modern whales.
Examining early whales revealed another clue.
To determine which of the hoofed mammals are most closely related to whales, scientists also examined their DNA. Scientists soon found whale’s nearest relative: the hippo!
| A．Their ancestors lived on land. |
| B．But many ancient mammals survived the extinction. |
| C．The whale breathed in the same way as mammals. |
| D．These whales had tiny legs, too small to be useful for walking. |
| E．As to what caused the extinction, opinions were divided among scientists. |
| F．The newly aquatic mammals kept some characteristics from their ancestors’ lives on land. |
| G．The ability to find new kinds of food in the water or live in a new environment gave these land animals an advantage. |
Noah's Ark is aimed at collecting eggs, embryos(胚胎), semen and DNA of these animals and storing them in liquid nitrogen. If certain species should become extinct, Dr. Duane Kraemer, a professor in Texas A & M's College of Veterinary, Medicine, says there would be enough of the basic building blocks to reintroduce the species in the future.
It is estimated that as many as 2, 000 species of mammals, birds and reptiles will probably become extinct in over 100 years. The panda, native only to China, is in danger of becoming extinct in the next 25 years. This week, Chinese scientists said they grew an embryo by introducing cells from a dead female panda into the egg cells of a Japanese white rabbit. They are now trying to implant the embryo into a host animal. The entire procedure could take from three to five years to complete. "The nuclear transfer of one species to another is not easy, but the lack of available panda eggs could be a major problem," Kraemer believes. "They will probably have to do several hundred transfers to result in one pregnancy (having a baby). It takes a long time and it's difficult, but this could be groundbreaking science if it works. They are certainly not putting any live pandas at risk, so it is worth the effort," adds Kraemer, who is one of the leaders of the Project at Texas A&M, the first-ever attempt at cloning a dog.
"They are trying to do something that's never been done, and this is very similar to our work in Noah's Ark. We're both trying to save animals that face extinction. I certainly appreciate their effort and there's a lot we can learn from what they are attempting to do. The cooperation between us is very much needed."
1. The final aim of "Noah's Ark" project is to ___________.
| A．make efforts to clone the endangered pandas |
| B．save endangered animals from dying out |
| C．collect DNA of endangered animals to study |
| D．transfer the nuclear of one animal to another |
| A．the long time lasting cloning research could be successful. |
| B．the eggs transfers immediately result in having a baby. |
| C．the lack of nuclear transfer could be a major problem to have new pandas. |
| D．if species should die out, basic building blocks would heal them. |
| A．China's Success in Pandas Cloning |
| B．Helping Ways to Avoid Extinction |
| C．Exploring the Possibility to Clone Pandas |
| D．The Practice in Noah's Ark |
| A．Kraemer and his team have succeeded in cloning a panda |
| B．scientists try to implant a panda's egg into a rabbit |
| C．Kraemer will work with Chinese scientists in clone researches |
| D．about two thousand species are to die out in a century |
【推荐2】The world is a greener place than it was 20 years ago. A study published in the journal “Nature Sustainability” said that recent satellite data reveals a greening pattern that is strikingly prominent in China and India. The study shows that human activity in China and India dominates this greening of the planet, thanks to tree planting and agriculture. The effect comes mostly from ambitious tree-planting programs in China and intensive agriculture in both countries.
“China and India account for one-third of the greening, ” said lead author Chi Chen of Boston University. “ That is a surprising finding, considering the vague idea of land degradation (毁坏) in populous countries from overexploitation, ” added Chen.
China alone accounts for 25 percent of the global net increase in leaf area with only 6.6 percent of global vegetated area. The greening in China is from forests (42 percent) and croplands (32 percent), but in India, it is mostly from croplands (82 percent) with minor contribution from forests (4.4 percent).
China’s outsized contribution to the global greening trend comes in large part from its programs to conserve and expand forests with the goal of preventing land degradation, air pollution, and climate change.
“Once people realize there is a problem, they tend to fix it,” said Rama Nemani, research scientist and co-author of the study. “In the 1970s and 80s in India and China, the situation around vegetation loss was not good. In the 1990s, people realized it, and today things have improved. Now we see that humans are contributing.”
Land area used to grow crops is comparable in China and India—more than 770, 000 square miles—and has not changed much since the early 2000s. Yet these regions have greatly increased both their annual total green leaf area and their food production.
This was achieved through multiple cropping practices, where a field is replanted to produce another harvest several times a year. Production of grains, vegetables, fruits and more have increased by about 35%～40% since 2000 to feed their large populations.
1. What did the study mainly find?| A．India and China are leading the global greening effort. |
| B．Intensive agriculture is the cause of global land degradation. |
| C．China and India has got the largest forest coverage in the world. |
| D．Agriculture is more helpful in expanding green areas than tree-planting. |
| A．India reduced cropland to prevent the overexploitation. |
| B．India increased forest by planting around croplands. |
| C．China changed more lands into forest by planting trees. |
| D．China controlled the increase of its population. |
| A．Ambitious. | B．Responsible. |
| C．Passionate . | D．Tolerant. |
| A．Forest. | B．Trees. |
| C．Cropland. | D．Food |
Having worked in a nature reserve for 30 years, Hou Tiguo has developed a special ability—he can tell what kind of birds are around simply by their singing. “I can also tell whether they are happy or unhappy,” he added with a big smile.
The 52-year-old’s home, Baihualing, a village in Yunnan province, is well-known for the diversity of birds. He recalled, “In the 1970s, people were so poor. Birds were often targeted as food, so almost all the children including me in the village were good at using slingshots (弹弓).”
His life changed in 1989, when a couple hiking through the mountains visited Baihualing. They asked him to be their guide and lead them to good bird-watching spots. He said, “That was the first time I had made money from birds without killing them.”
Inspired by that, the villagers built a reserve to feed birds and protect the habitat (栖息地) of birds. In the decades that followed, more bird-watchers visited the village. The village became a popular destination for bird lovers, and most villagers have turned into bird protectors and engaged in serving bird-loving tourists.
In the village, there are more than 60 “bird guides” like Hou. More than 20 guesthouses which have hosted visitors from more than 100 countries bring in a total income of 15 million yuan every year. “During the peak season, I serve nearly 100 tourists a day. Thanks to the birds, our life is not what it used to be any more.” Hou said, adding that he takes his 3-year-old grandson with him every day to feed birds and teaches him to love and respect them.
1. What was the life in Baihualin like in the 1970s?2. When did Hou begin to change his life?
3. What is the job for most villagers now?
4. Why does Hou take his 3-year-old grandson with him every day?
【推荐1】One of the hardest things in life is sticking to a healthy diet. Experts recommend you plan your meals in advance, so you aren’t attracted when faced with less-than-healthy choices. It’s said that the average American eats almost 25 percent of their daily calories from snacking (零食) alone, and snacking is the leading cause of childhood obesity.
Therefore, there are two choices: Stop snacking (hard) or snack healthier (simple). But, for many of us, telling apart what’s “healthy” and how much to consume (消耗) are two different things. But, if you don’t keep the amount in check it can seriously ruin your diet. It’s easy to consume double or triple the amount. If you’re struggling to keep you and your family’s snacking under control, you may be interested in the new online store called NatureBox.com, offering a new service delivered right to your front door on a monthly basis.
After you sign up on their website and provide some information about your taste preferences and anything else, the company sends you a box every month containing a delicious selection of healthy snack foods. A box includes 12-15 servings across 4 to 5 different NatureBox snacks — enough to last you and your family for a month.
Each box costs just under $20 and shipping is always free. NatureBox is meant to fit your lifestyle by providing you with snacks you’ll enjoy and look forward to eating. You can easily order what you want to receive based on the snacks you love most. And now, NatureBox is offering an immediate 25% off their first order. Just enter the code “livehealthy” when you join.
1. We can learn from the passage that ________.| A．almost 25 percent of Americans’ daily calories are from snacking |
| B．NatureBox is the name of a new kind of healthy snacking |
| C．it is easy for people to control their amount of snacking in daily life |
| D．snack boxs from NatureBox are given to the customers for free |
| A．In danger. | B．In control. |
| C．In need. | D．In store. |
| A．NatureBox is a snack box given by the government free of charge. |
| B．Each box from NatureBox costs more than $20 . |
| C．NatureBox is an online store which sells healthy snacks. |
| D．A box from NatureBox contains snacks for a family to eat for a year. |
| A．the unhealthy eating habits of Americans |
| B．the development of healthy snacks in America |
| C．a way of keeping a healthy diet |
| D．a company that sells healthy snacks |
【推荐2】At Englands University of Plymouth, Professor Eduardo Miranda has been programming pairs of robots to compose music. Miranda's robots have simple “ vocal cords”(声带)and are programmed to sing and to listen to each other. The robots' unique warbling sounds (颤音) do not perfectly match the human voice, but each machine is exactly sharing music with the other in a new and unique way.
Each robot is equipped with speakers, software that mimics the human voice, a mouth that opens as it “sings,” a microphone for ears, and a camera for eyes. The robots also move. Miranda hopes that by studying his robot vocalists, he can discover something about how and why humans create, perform, and listen to music.
When the robots sing, first one robot makes six random sounds. Its partner responds with more sounds. The first robot analyzes the sounds to see if their sequences (序列)) are similar. If they are, it nods its head and commits the sounds to memory, and the second robot notices and “memorizes” the musical sequence, too. If the first robot thinks the sounds are too different, it shakes its head and both robots ignore the sounds. Then the process continues.
Miranda set up an experiment in which he left the two robots alone in his study for two weeks. When he returned, his little warblers had, by imitating each other, not only shared notes but combined them. The product of their cooperation was far from symphonic, but the robots had begun to combine the notes into their own self-developed “songs”.
With the help of his warbling robots, one of Miranda's goals is to create music that no human would ever compose. Miranda believes the robots are ideal for this purpose because they would not be influenced by any existing musical styles or rules.
1. Which is closest in meaning to the underlined word “mimics” in Paragraph 2?| A．Substitutes. | B．Interrupts. |
| C．Controls. | D．Copies. |
| A．They interacted with each other. |
| B．They ignored the unique sound. |
| C．They learned to sing better than humans. |
| D．They committed random sounds to memory. |
| A．Sing as well as humans do. | B．Create new styles of music. |
| C．Memorize a variety of music. | D．Promote traditional musical forms. |
| A．Future robots. | B．Special songs. |
| C．Music by robots. | D．Experiments by Miranda. |
【推荐3】These days, tourism is back in full swing. An increasing number of people prefer to take a break from big city life and start exploring those harder-to-reach towns.
Paraty, Brazil
Paray is a bays de town halfway between Rio and Sao Paulo. Here, life moves at the pace of a horse-and-cart moving across the road (no cars allowed in the historic Old Town). The boats in the harbor are not just there to look good. Pick your favorite and set sail for a deserted island beach nearby.
Avignon, France
One of the most recognizable historic towns is found in the south-eastern part of France. The Palace of the Popes here defines the city and is the city and is visible from a far. It once housed Europe’s largest library, and became a hotbed for thinkers, philosophers, composers, and musicians. Now it is protected by UNESCO as a world heritage site. Four million tourists visit Avignon every year to explore the ancient architecture.
Sakrisoy and Reine, Norway
This pair of tiny finishing villages sit far, far north. Admittedly, they are a bit of pain to reach: The long (but beautiful!) journey there will require some combination of one or two fights, a bus or a boat. If you can make it that far, though, you’ll be rewarded with some of the most impressive scenery on Earth. Look out across the mountains from the hike or enjoy the Northern Lights.
Old San Juan, US
The oldest settlement in the country was founded in the early 16th century. Today everything here is colorful: the houses differ in color and style and even the pavements are made of the blue bricks, making it a very attractive and amusing place.
1. What can visitors do in Avignon, France?| A．Take a boat trip. |
| B．Enjoy the Northern Lights. |
| C．Admire ancient architecture. |
| D．Explore the largest library in the world. |
| A．Paraty, Brazil. | B．Avignon, France. |
| C．Sakrisoy and Reine, Norway. | D．Old San Juan, US. |
| A．In a wellness book. | B．In a travel magazine. |
| C．In an adventure guide. | D．In a geography textbook. |
