Peppered moth caterpillars (桦尺蠖毛虫)live north of the equator. But if you’ve never seen one, don’t feel bad: They’re experts at blending in (融为一体). Each caterpillar looks like the branch it stays on, straightening its body into a stick-like shape. It also changes its color to match the branch’s color, whether white, green or brown.
According to a paper published in Communications Biology, the caterpillars sense the color of their surroundings not only with their eyes but also with their skin.
Ilik Saccheri, an author of the paper, normally studies the adult moth. This requires keeping a lot of caterpillars around. Years of observation awakened his curiosity about their color-changing abilities. Each caterpillar hatches tiny and black, and in its early days is blown around by the wind. Once it falls on a plant, it must disguise itself to avoid being spotted by birds.
“I was a bit disbelieving that they could change that only using their eyes,” Dr. Saccheri said.
Amy Eacock, a graduate student in Dr. Saccheri’s lab decided to investigate. First, she tested the caterpillars’ eyes for light-sensitive proteins called opsins (视蛋白). “We did the skin as kind of a negative control,” said Dr. Eacock. “But then we found they were expressed in the skin as highly as they were in the head.”
That’s when she suggested blindfolding the caterpillars. The researchers could cover their eyes, place them on different-colored dowels (木钉) , and see if they still changed to match.
“I thought it was kind of a crazy idea,” Dr. Saccheri said. The blindfolding itself was a difficult task, involving black paint, a tiny paintbrush, a microscope and lots of patience, Dr. Eacock said. Caterpillars molt (蜕皮) several times over their lives, which required that they be blindfolded again frequently.
But Dr. Eacock persisted, eventually testing more than 300 caterpillars. Over and over again, the blindfolded caterpillars successfully changed color to blend in.
Many questions remain, but the behavior alone impressed the researchers. Dr. Eacock said, “I remember turning to Ilik one day and saying, ‘You know what? The caterpillars are cooler than the moths.’” “Yes. They’re pretty amazing,” Dr. Saccheri agreed.
1. What can we learn about peppered moth caterpillars?| A．They feed on fresh tree branches. |
| B．They can be found easily across the world. |
| C．They can adapt to different environments. |
| D．They change their body color to match living conditions. |
| A．Caterpillars have a fear of height. |
| B．There are opsins in caterpillars’ skin. |
| C．Caterpillars molt several times in their life. |
| D．There is something strange in caterpillars’ eyes. |
| A．It was hard to operate. |
| B．It was well designed. |
| C．It was inspiring but the evidence was unreliable. |
| D．It was a failure but the methods deserved praise. |
| A．To solve a mystery. | B．To introduce a new species. |
| C．To present a scientific study. | D．To awaken readers’ curiosity. |
相似题推荐
【推荐1】＂Has anyone seen Charge?"I asked,only half expecting a reply.The kids were running around the house,each doing their own thing,and my husband was watching the football game. Since she had only been out of sight for a few hours,I wasn't overly concerned.I thought she must be under one of the kids' beds,hiding from all the mess that was normal for a Sunday afternoon in our home.
Charge was not good looking,to put it kindly.It wasn't her fault;she was simply gifted with the worst appearance in her background.
My husband had found Charge wandering along the freeway one day on his way home from work.She looked as though she hadn't eaten in weeks,so he stopped and fed her with bits of his leftover lunch.Not knowing what to do,he brought her home with the hope of finding her owners or at least a loving family that would take her.However,once she was in the house,the kids were determined not to let her go.After a day or two of begging,we unwillingly gave in and told them we could keep her.
After observing her actions for a few days,I found she was extremely distrustful and afraid of everyone.In time,though,she came to love the kids and slept on their beds every night.I wondered if what she had experienced had conditioned her to be protective of those who were hurting.Every time the kids cried,Charge would run to them and gently offer her comforting paw. Unlike our cat, who had recently given birth to five kittens,Charge would have been a great mother.
When I was finally able to get everyone's attention at the dinner table,I asked again if anyone had seen Charge.After an all-in-one voice"No",I decided to take a look around the neighborhood.
"Who wants to go look for Charge with me?" I asked as I opened the door of the hall closet and reached in to gel my shoes.
“Charge!"I cried,because there she was in the closet!She looked up at me from inside the little cats'box as if to say,"Shhh,I just got them to sleep!"
We usually kept the closet door open a bit so our mamma cat could go in and feed her kittens, but she always left as soon as she finished nursing.Obviously,Charge knew they needed more mamma time and was more than willing to help out.
The kids smiled upon seeing the dog with the kittens.My husband shook his head and said,“Only you,Charge.Only you!"
Charge continued to mother the kittens until they were placed in their new homes.Charge may not have been an attractive dog,but she truly had her inner beauty.
1. It can be inferred from the first paragraph that_| A．the kids were not willing to play with Charge |
| B．the author didn't worry too much about Charge |
| C．Charge liked playing hide-and-seek games with the kids |
| D．the author's husband was watching the football game with the kids |
| A．fed her with his lunch |
| B．decided to adopt her |
| C．felt pity for her |
| D．helped to find her owner |
| A．It was really an energetic hunter. |
| B．It was too selfish and lazy. |
| C．It was quite clean and lovely. |
| D．It was not a very caring mother. |
| A．prove one's past could influence their characteristics |
| B．indicate those who love the kids will be loved by others |
| C．inform a pet dog can bring both joy and sadness to its owner |
| D．show beauty isn't in the face but from the bottom of the heart |
| A．The most beautiful Charge |
| B．The greatest mamma |
| C．A loving story |
| D．A special Sunday |
【推荐2】Toronto Zoo
You may think you need to look far and wide for the best zoos in the world but there’s an impressive zoo right here in Canada. The Toronto Zoo is home to over 16,000 animals. The zoo also has an amazing Discovery Zone for children to learn more about the animals and their natural habits. Another thing that makes this zoo worthy of a visit? Its conservation policy. The Toronto Zoo has helped in the effort to conserve endangered animals from all around the world, and is presently one of the very few animal-friendly zoos in North America.
Basel Zoological Garden
Basel Zoo, which lies in Basel, Switzerland is a non-profit 200 that first opened up in 1874 making it one of the word’s oldest. Rated as one of the top 200 in the world by Forbes Traveler in 2008. Basel Zoo is an awe-inspiring sight to see. There are presently over 6, 000 unique animals housed there. Basel Zoo has also bred(繁殖)several endangered animals, making it one of the most animal-friendly zoos, too,
National Zoological Gardens of South Africa
As the largest 200 in South Africa, there isn’t much you won ‘t see at this amazing habitat for animals. While many of the animals have been bred and raised in the zoo, there is enough room in this vast park for the animals to run freely. Here you’ll find African animals and the third latest collection of fantastic trees in South Africa. If you’re looking for an adventure—packed day, with its magnificent animals in a cruelty—free environment, a trip to pretoria, it may be your best bet.
1. How many aspect make Toronto Zoo special?| A．Five. |
| B．Four. |
| C．Three. |
| D．Two. |
| A．It offers children a special zone. |
| B．Visitors can see animals run freely. |
| C．It lies on the mountain top. |
| D．It doesn’t run for profits. |
| A．National Zoological Gardens. |
| B．Discovery Zone. |
| C．Basel Zoological Garden. |
| D．Toronto Zoo. |
【推荐3】While elephants born without tusks (长牙)are not unheard of，they normally form just 2 to 6 percent of the population. However, that is not the case at Mozambique’s Gorongosa National Park, where an astonishing 33 percent of female elephants born after the country’s civil war ended in 1992 are tuskless. While that may appear to be just a coincidence, Joyce Poole, an elephant behavior expert, has another theory. The researcher thinks we may be witnessing unnatural evolution of the species due to the constant hunting of elephants for valuable ivory.
Poole says before the country’s 15-year-long civil war, the 100,000-acre park was home to over 4,000 elephants. However, by the time the conflict ended in 1992, about 90 percent of them had been killed for ivory to help finance weapons (武器)and meat to feed the soldiers. Of the less than 200 survivors, over 50 percent of adult females had no tusks. Therefore, it is not surprising that the park’s tuskless elephant population has grown greatly.
This is not the first time researchers have observed a great change in the population of elephants. At Zambia’s South Luangwa National Park and Lupande Game Management Area， areas which were heavily hunted in the 1970s and 1980s, 35% of elephants 25 years or older and 13% of those younger than 25 are now without tusks. A 2008 study published found that the number of tuskless females at the Ruaha National Park in Tanzania went from 10.5 percent in 1969 to almost 40 percent in 1989, largely due to illegal hunting for ivory.
The recent ban on ivory in both the US and China should help get rid of, or at least reduce, elephant hunting. However, scientists are not sure how long it will take for elephants with a higher rate of tuskless females, to change the trend.
1. What is the probable cause of the phenomenon mentioned in Paragraph 1 ?| A．Illegal hunting. | B．Constant farming. |
| C．A pure coincidence. | D．Natural evolution. |
| A．To get funds by selling ivory. |
| B．To develop new weapons. |
| C．To provide food for local people. |
| D．To make ivory products. |
| A．Gorongonsa National Park. |
| B．South Luangwa National Park. |
| C．The Ruaha National Park. |
| D．Lupande Game Management Area. |
| A．Elephants facing greater danger. |
| B．Elephants growing more slowly. |
| C．Fewer female elephants staying alive. |
| D．More female elephants being tuskless. |
【推荐1】Does just thinking about stepping inside a gym make you feel exhausted? If so, here's some good news. One of the world's largest studies on physical activity has found that doing household chores（家务事）can be just as effective as running or working out when it comes to cutting your risk of heart disease and extending your life.
A team of researchers discovered that people enjoyed the same health benefits whether they were going to the gym, walking to work or doing household chores. Indeed, performing 30 minutes of any kind of physical activity five days a week could reduce your risk of dying from any causes by 28% and your rate of heart disease by 20%.
And, again, the positive effects were the same whether someone was working out, walking or doing chores such as mopping the floor or gardening.
“Walking for at least 30 minutes most days of the week has a massive benefit, and high levels of physical activity is associated with even lower risk of illness," lead researcher Scott Lear said about the findings. “By including low and middle-income countries in this study, we were able to determine the benefit of activities such as having an active job or even doing household chores,” Lear said. He noted that 1 in 4 people worldwide do not get 30 minutes of exercise a day, five times a week.
Interestingly enough, the Canadian study found no ceiling on the benefits of exercise and "no risks associated with extremely high levels of physical activity", defined as more than 2,500 minutes, or more than 41 hours per week. Lear said that those who spent more than 750 minutes walking quickly each week lowered their risk of premature death by 36%.
1. What can we infer about the study from paragraph1?| A．Women should do more housework than men. |
| B．Doing housework may help to live long and healthy. |
| C．People with heart disease had better do less housework. |
| D．Doing housework makes people feel less tired than going to gym. |
| A．Sitting long will take the health away. |
| B．The exercises will make life meaningful. |
| C．It's a good idea to walk less than 30 minutes a day. |
| D．High levels of physical activity can reduce disease risk. |
| A．Statistics. | B．Voices. |
| C．Examples. | D．Experiments. |
| A．Exercise Moves for Better Strength and Balance |
| B．Risks From High Levels of Physical Activity |
| C．Household Chores May Be a Secret to Living Longer |
| D．The Two Factors Determine the Benefit of Activities |
【推荐2】The need to feed a growing population is putting much pressure on the world's supply of water. With 97% of the world's water too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage(短缺)seems strange to someone fortunate enough to live in a high rainfall country, many of the world's agricultural industries experience constant water shortages.
Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution(重新分配)are very high. Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered. Where valleys(山谷)are flooded to create dams, houses are lost and wildlife homes destroyed. Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other. Each country must therefore rely on the management of its own water to supply its farming requirements. This is particularly troubling for countries with agricultural industries in areas dependent on irrigation. In Texas, farmers' overuse of irrigation water has resulted in a 25% reduction of the water stores.
In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.
Saudi Arabia's attempts to grow wheat in desert areas have seen the pumping of huge quantities of irrigation water from underground reserves. Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.
1. From the first two paragraphs we learn that________.| A．much of the world's water is available for use |
| B．people in high rainfall countries feel lucky |
| C．the costs of water redistribution should be considered |
| D．water can be easily carried through pipes across the world |
| A．The water stores in Texas have been reduced by 75%. |
| B．Most industries in the world suffer from water shortages. |
| C．The underground water in Saudi Arabia might run out in 50 years. |
| D．Good management of water use resulted from the project in the Central Valley. |
| A．water supply and increasing population |
| B．water use management and agriculture |
| C．water redistribution and wildlife protection |
| D．water shortages and environmental protection |
【推荐3】Scientists in Switzerland have used lasers(激光)to change the path of a lightning strike. The experiment was carried out on Säntis mountain in Switzerland, near a radio and TV tower that’s hit by lightning about 100 times a year. Using a special laser, the researchers were able to guide the lightning strike.
Scientists have been trying to find a way to protect buildings from lightning for a long time. Currently, the best way to protect buildings from lightning is by putting metal rods(棒)on the buildings. But lightning rods can only protect a small area. If a building is very large, it needs a lot of lightning rods. But some buildings—such as airports—are so large that it’s difficult to protect the whole building using lightning rods.
Another idea is to use lasers to guide lightning. The idea of using lasers to guide lightning isn’t new. Scientists have been working on the idea for over 20 years. They have successfully guided lightning with lasers inside a laboratory.
But until recently, scientists haven’t been able to guide lightning with lasers outside. That changed in the summer of 2021. Using a powerful laser that can fire about 1,000 times a second, scientists in Switzerland were able to guide lightning for 164 feet away.
The heat from the laser creates a path of air that is less thick than the air around it. The path also has a special charge. The lightning can follow this path almost as if it were a lightning rod.
But despite the progress, the laser still didn’t guide the lightning as far as the scientists would like. To protect buildings from most lightning, lasers will have to guide the lightning for a much longer distance. The laser is also very expensive. The scientists say it cost about $2 billion. It will probably take 10 or more years before a laser like this is truly able to protect large buildings.
1. What is this new technology expected to protect?| A．High buildings. | B．Large buildings. |
| C．Important buildings. | D．Complex buildings. |
| A．It is still being tested. | B．It works only in the lab. |
| C．It is an invention of Swiss scientists. | D．It cools the air around the lightning. |
| A．Its cost control. | B．Its disadvantages. |
| C．Its wide application. | D．Its promising future. |
| A．Guide Lightning With a Laser | B．Lightning Rods Are out of Date |
| C．Use Lasers to Block Lightning | D．Lightning Can Be Used to Serve People |
【推荐1】Ireland has had a very difficult history. The problems started in the 16th century when English rulers tried to vanquish Ireland. For hundreds of years, the Irish people fought against the English. Finally, in 1921, the British government was forced to give independence to the south of Ireland. The result is that today there are two “Irelands”. Northern Ireland, in the north, is part of the United Kingdom. The Republic of Ireland, in the south, is an independent country.
In the 1840s the main crop, potatoes, was affected by disease and about 750,000 people died of hunger. This, and a shortage of work, forced many people to leave Ireland and live in the USA, the UK, Australia and Canada. As a result, the population fell from 8.2 million in 1841 to 6.6 million in 1851.
For many years, the majority of Irish people earned their living as farmers. Though many people still follow the routine nowadays, more and more people are moving to the cities to work in factories and offices. Life in the cities is very different from life in the countryside, where things move at a quieter and slower pace.
The Irish are famous for being warm-hearted and friendly. Oscar Wilde, a famous Irish writer, once said that the Irish were “the greatest talkers since the Greeks”. Since independence, Ireland has revived (复兴) its own culture of music, language, literature and singing. Different areas have different styles of old Irish songs which are sung without instruments. Other kinds of Irish music use many different instruments such as the violin, whistles, etc.
1. What does the underlined word “vanquish” in Paragraph 1 probably mean?| A．Conquer. | B．Ruin. | C．Protect. | D．Free. |
| A．The Irish were killed by the English rulers. |
| B．The Irish were affected by a deadly disease. |
| C．The Irish were not eager to give birth to babies. |
| D．The Irish suffered from food and work shortage. |
| A．By working in the fields. | B．By working in factories. |
| C．By trading with other countries. | D．By performing musical instruments. |
| A．Life in Ireland | B．Ireland, Past and Present |
| C．A Very Difficult History | D．The Independence of Ireland |
【推荐2】Unhappily married for many years, Peter waited until his children were grown up before he divorced their mother. He hoped this would make the experience less unhappy for them. Yet in the six years since, he has not seen either of his two sons. “For me it has been completely destructive,” he says. “I get teary when I think about them.”
Though people tend not to talk about it much, family estrangement seems to be widespread in America. The relationship most commonly cut off is that between parent and adult child, and in most cases it is the child who holds the knife.
Because family estrangement has been a subject of research only for the past decade, there are no data to show whether it is becoming more common. But many sociologists and psychologists think it is. In one way this seems surprising. Divorce increases the risk of family divisions. Yet in recent years, America’s divorce rate has fallen. So Dr. Coleman thinks other factors are making parent-child estrangements likelier than ever.
A rise in individualism that emphasizes personal happiness is the biggest factor. Realization of personal value has increasingly come to take the place of filial duty, says Dr. Coleman. In some ways it is a positive development: people find it easier to separate from parents who have been pushy. But it can also carry heavy costs.
Another factor is that those who decide to break off contact with their parents find support online. Posts on internet forums for people who Want to break ties with their parents show strangers advising an immediate break in contact. This may make it easier to put aside their feelings of guilt.
Raising awareness about the issue in this Way is likely to be important not only because some broken relationships may be fixable. Parent-child estrangement has negative effects beyond the heartbreak it causes. Research suggests that the habit of cutting off relatives is likely to spread in families. But most immediately, it is likely to increase loneliness in old age.
1. What is the function of the first paragraph?| A．To explain a reason. | B．To introduce the topic. |
| C．To make a suggestion. | D．To give an example. |
| A．The research data | B．The risk of divisions |
| C．Family estrangement. | D．Parent-child relationship. |
| A．By finding support online. | B．By seeking personal happiness. |
| C．By performing filial duty. | D．By posting on Internet forums. |
| A．Causing heartbreak. | B．Breaking parent-child relationships. |
| C．Leading to awful loneliness in old age. | D．Spreading the habit of cutting off relatives. |
【推荐3】You may have heard that some plants and animals are endangered. What does that mean exactly?
Endangered means there are very few of that kind still alive. Someday they might become extinct. You may wonder what people can do to help them.
Plant trees
As the date of Earth Day roughly coincides with U.S.Arbor Day, planting trees is a popular Earth Day activity. Trees helps to reduce greenhouse gas emissions, clean pollution, secure soil in place to prevent erosion, and provide homes for many birds, insects and other animals.
Why not welcome these nonhuman neighbors into your yard？ Here is how to do it. Instead of mowing the entire yard, leave a few sections unmoved.
Clean up litter in your community
Many groups use the weekend of Earth Day to clear roadways, highways and neighborhood streets of litter that has accumulated since the last clean-up day.
| A．Welcome animals into your yard |
| B．Choose flowers that are native to your area. |
| C．One way is to protect the animals’ or plants’ habitats |
| D．Bees, butterflies, and many other insects will find this inviting |
| E．It’s a wonderful community project that you can do as an individual or with a group |
| F．So planting trees is a long -lasting act you can do to celebrate Earth Day |
| G．Encourage people to respect wild spaces by not damaging animal habitats, littering,and dumpling in the water. |
