In the hills outside Missoula, Montana, wildlife biologists are looking at how climate change affects something very small: the snowshoe hare.
Life for snowshoe hares is pretty stressful 一 almost everything in the forest wants to eat them.
Alex Kumar, a graduate student at the University of Montana, lists the animals that are hungry for hares. “Lynx, foxes, coyotes, […. even] red squirrels.”
Kumar and field technician Tucker Seitz spend months searching these woods for hares, often listening for signals from hares they've already put radio collars on.
They catch other hares with wire traps about the size of a breadbox, with some apple as bait (诱饵). Most of the hares they track live less than a year — a hazard (风险）of being what Kumar calls “the cheeseburger of the ecosystem”.
But snowshoe hares have a special skill: camouflage. They're brown during the summer, but turn white for the snowy winter months.
“There’s times when you’re tracking them and you know they’re really, really dose, and you just can’t find them,” he says.
Hares switch color in the spring and fall in response to light, when the days get longer or shorter. But if the snow comes late, you get a white hare on brown ground.
“And they really think that they’re camouflaged,” Kumar says. “They act like we can’t see them.”
Kumar calls this “mismatching,” and it's becoming more of a concern with climate change.
“If the hares are consistently molting (脱毛) at the same time, year after year, and the snowfall comes later and melts earlier, there’s going to be more and more times when hares are mismatched,” he says.
Scott Mills of North Carolina State University leads the research. He says they're finding that mismatched hares die at higher rates. That’s a concern for the threatened Canada lynx, which mainly eats these hares.
“It’s a very clear connection to a single climate change stressor,” Mills says.
Hares might be able to adapt over time. Some snowshoe hares in Washington State don't turn white at all. Mills is trying to figure out whether hares and other wildlife can adapt as fast as the climate is changing.
“But how fast is too fast?” he asks.
1. The word “camouflage”（Paragraph 6) is closest in meaning to .| A．escaping | B．hiding |
| C．fighting | D．scaring |
| A．change their fur color to white too late |
| B．haven’t adapted to climate change |
| C．can no longer adapt to the change of light in spring and fall |
| D．find it more and more difficult to molt at the same time each year |
| A．Approving. | B．Enthusiastic. |
| C．Concerned. | D．Doubtful. |
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【推荐1】A Colourful Puzzle
People often wear clothing with colours that express something about themselves. A happy person might choose to wear a bright yellow shirt. A swimmer might wear a sea-blue dress.
Animals appear in different colours too, but they don’t get to pick what they wear every morning. Scientists have known for a long time about some of the ways animal colouring can be beneficial. They know that some animals’ colours attract mates or show who is boss. Other animals’ colours blend(融合) in with their environment; thus the animals cannot be seen by their enemies. Still, scientists do not fully understand why blue jays are blue or why rainforest frogs are golden. Now many scientists are working hard to figure out the puzzles of animal colours.
Part of the answer can be found in an animal’s habitat, the place where it lives. It turns out that many animals — especially birds, fish, and reptiles — can see more colours than humans can. These creatures notice colours that stand out in their habitat. For example, forests are mostly green, brown, and yellow. For an animal to be seen by others of its species, it would have to be a different colour than its background. That explains why you can find birds of many shades of blue living in forests.
Another piece of the puzzle lies in what an animal eats. Birds often eat things that have chemicals in them called “carotenoids”(类胡萝卜素). These chemicals are what make tomatoes red and bell peppers bright orange or yellow. When birds eat these foods, the carotenoids affect the colour of their feathers. For example, a cardinal’s bright red feathers will become lighter or darker depending on how many berries it has found to eat.
Some animals do not have any colour at all — but they are not just white; they are transparent(透明的)! Transparent animals live mostly in the ocean. This amazing wonder of nature came about because the animals needed a way to escape their enemies. They are often slow, defenseless creatures that would have no way of fighting back if larger animals wanted to eat them. Because there are few places to hide in the ocean, these creatures have to hide in plain sight. A good example of this kind of transparent creature is the jellyfish. A jellyfish’s body is almost all water, so it is very hard to see it floating in the ocean.
Animals come in all kinds of colours. Their colours are caused by many different factors, and most animals will remain the same colour for their whole lives. Think how lucky we are to get to change our feathers every day!
1. What is the main idea of this article?| A．Animals appear in many different colours. |
| B．Animals are unable to choose their colours. |
| C．Animals’ colours are caused by different factors. |
| D．Animals need colours to blend into their surroundings. |
| A．It marks the places they live in. |
| B．It shows the leader of the group. |
| C．It helps them to escape enemies. |
| D．It allows their mates to see them. |
| A．to identify group members |
| B．to show their personalities |
| C．to distinguish the group leader |
| D．to blend in with the environment |
| A．comparisons | B．explanations |
| C．order of events | D．order of importance |
【推荐2】Zhong Zhong and Hua Hua have made medical history as the first cloned primates (灵长目动物),with the efforts of a team of Chinese scientists.
According to the journal Cell , it is a milestone for biomedical research. It could potentially lead to the development of new treatments for human disease. But it also makes ethicists (伦理学者) about where this all might lead. Do Zhong Zhong and Hua Hua suggest the coming of human cloning?
Born in 1996, Dolly the sheep was the first cloned mammal, and was followed by many more, including dogs, rabbits and pigs. But researchers were unable to clone primates because the genes involved didn’t react well to the procedure. Over the years, a handful of research institutions have tried and failed to birth a live monkey clone.
The successful team, at Shanghai’s Chinese Academy of Sciences, used the same basic method that created Dolly but had failed in subsequent(随后的) primate cloning attempts. It’s called somatic（躯体）cell nuclear transfer and involves transferring DNA from adult cells into eggs that have had their own DNA removed. Without the addition of sperm(精子), the eggs are stimulated （刺激）chemically to develop into an embryo that’s a clone of the DNA donor(提供者). The embryo is then placed into a substitue(替代) for gestation（妊娠）.
The researchers modified the approach in two important ways, however. Rather than use adult cells in the DNA transfer, they used fetal (胎儿)cells, which react better to chemical stimuli（刺激）for embryo development, says Mu-ming Poo, director of the academy’s Institute of Neuroscience and a co-autho of the paper. They also fine-tuned the cell transfer process to minimize damage to the eggs
As for creating human clones, Poo says the research shows it can be done, but he and his team have no interest. “Besides many technical dificulties that remain to be overcome, we see no justifiable reason to do human cloning,” says Poo, “nor would the societies around the world permit such an attempt.”
While human cells may be cloned experimentally, for example to research tissue regeneration, the cloning of an entire human is illegal in more than 70 countries, according to the Center for Genetics and Society. U.S. law does not ban it, but over a dozen states do. (Discover 2019J&F,P60.)
1. About somatic cell nuclear transfer, which of the following statements is true?| A．It needs the combination of sperm and eggs. |
| B．The eggs keep their own DNA in the process. |
| C．The embryo has the DNA of the adult donor. |
| D．The embryo gestates in the eggs donor’s body. |
| A．acceptable. | B．incredible. | C．valuable. | D．reliable. |
| A．The right donor cells. | B．The fine-tuned transfer process. |
| C．The united team. | D．The reduced damage to the eggs. |
| A．Nature Exploration | B．Science Magazine |
| C．Medicine World | D．World Wonders |
【推荐3】Teak is a large tree that grows in tropical(热带的) forests. It’s often used for outdoor furniture, since it’s more resistant to the elements than other types of wood. When untreated, it tends to fade to a grayish color, so it is often stained(着色). Before being able to stain teak furniture, you’ll need to sand and smooth the wood first.
Wipe dirt and dust off. You can use a dry paper towed or a cloth to brush any dirt off. If there are more tenacious spots to clean off, you can use a wet rag to rub them clean. Sand rough spots with 120 grit sandpaper. After that, use 220 grit sandpaper on the whole surface. Wipe any wood dust off with a dry rag before continuing.
Paint on a layer of sanding sealer(底漆). This will make the surface smoother and will get the wood stain better attached. Once the sealer has started to dry, use a clean cloth to wipe off any sealer that’s still pooled at the top of the wood. This will prevent spots from forming on the wood. Let the sealer dry completely. It should only take a few hours for the sealer to dry completely. You should sand the surface a few times before continuing to smooth out any spots where the sealer might not have dried evenly.
When painting on a layer of stain, a brush will do fine. Apply an even coat all over. Wipe off any stain not absorbed by the wood. Use a clean dry rag to wipe off extra stain. Let the wood stain dry. The amount of time it takes for the stain to completely dry will depend on how thick of a layer you used. Avoid touching the stain too much if it’s still wet. After the first coat has dried, take a moment to see if you’re satisfied with the color. If you want your furniture to be darker, you can add another coat of wood stain, right on top of the previous layer, following the same process.
1. What do we know about teak?| A．It is not easy to be damaged. |
| B．It bears an ugly original color. |
| C．It is made into the best furniture. |
| D．It grows in the hot and dry areas. |
| A．Huge. |
| B．Obvious. |
| C．Stubborn. |
| D．Colorful. |
| A．to get rid of increasing sport |
| B．to help the sealer dry completely |
| C．to get the wood stain better stuck |
| D．to make sure the surface is smooth |
| A．Wipe dirt and dust off again. |
| B．Paint on a layer of stain once more. |
| C．Paint on a layer of sanding sealer twice. |
| D．Repeat the whole process of coloring teak. |
