【备战2023高考英语】全国甲卷真题变式：02 阅读·科普类

Goffin's cockatoos, a kind of small parrot native to Australasia, have been shown to have similar shape-recognition abilities to a human two-year-old. Though not known to use tools in the wild, the birds have proved skilful at tool use while kept in the cage. In a recent experiment, cockatoos were presented with a box with a nut inside it. The clear front of the box had a "keyhole" in a geometric shape, and the birds were given five differently shaped "keys" to choose from. Inserting the correct "key" would let out the nut.

In humans, babies can put a round shape in a round hole from around one year of age, but it will be another year before they are able to do the same with less symmetrical（对称的） shapes. his ability to recognize that a shape will need to be turned in a specific direction before it will fit is called an "allocentric frame of reference". In the experiment, Goffin's cockatoos were able to select the right tool for the job, in most cases, by visual recognition alone. Where trial-and-error was used, the cockatoos did better than monkeys in similar tests. This indicates that Goffin's cockatoos do indeed possess an allocentric frame of reference when moving objects in space, similar to two-year-old babies.

The next step, according to the researchers, is to try and work out whether the cockatoos rely entirely on visual clues（线索）, or also use a sense of touch in making their shape selections.

The rapid pace of global warming and its effects on habitats raise the question of whether species are able to keep up so that they remain in suitable living conditions. Some animals can move fast to adjust to a swiftly changing climate. Plants, being less mobile, rely on means such as seed dispersal(传播) by animals, wind or water to move to new areas, but this redistribution typically occurs within one kilometre of the original plant.

When the climate in a plant's usual range becomes hotter than it can tolerate, it must find new, cooler areas that might lie many kilometres away. One explanation for long-distance seed dispersal is through transport by migratory (迁徙的) birds. Such birds swallow seeds when eating fruit and can move them tens or hundreds of kilometres outside the range of a plant species.

Gonzáiez-Vary and colleagues report how plants might be able to keep pace with rapid climate change with the help of migratory birds. The authors analysed the fruiting times of plants, patterns of bird migration and the interactions between fruit-eating birds and fleshy-fruited plants across Europe. Plants with fleshy fruits were chosen for this study because most of their seed transport is by migratory birds, and because fleshy-fruited plants are an important part of the woody-plant community in Europe. The common approach until now has been to predict plant dispersal using models fitted to abiotic (非生物的) factors such as the current climate. Gonzáiez-Vary instead analysed an impressive data set of 949 different seed-dispersal interactions between bird and plant communities, together with data on entire fruiting times and migratory patterns of birds across Europe. The researchers also analysed DNA traces from bird wastes to identify the plants and birds responsible for seed dispersal.

Around the globe far more bird species are losing ground than gaining, according to an expansive review of a half-century of bird population research published in the journal Annual Review of Environment and Resources in May.

The review, entitled The State of the World's Birds, showed that more than 5,200 different species of birds-just shy of half the world's total-are known or suspected to be declining. Around 3,800 species are relatively stable, and fewer than 700 species show increases. Among birds on the IUCN Red List of Threatened Species, almost 400 birds worldwide have had their conservation status changed for the worse in the past three decades (moving from vulnerable to threatened, or threatened to endangered) — five times more than the number of bird species with an IUCN status that has changed for the better.

"After documenting the loss of nearly 3 billion birds in North America alone (according to a 2019 study published in the journal Science), it was disturbing to see the same patterns of population declines and extinction occurring globally," says review coauthor Ken Rosenberg, a conservation scientist now retired from the Cormell Lab of Omithology.

The review points to disappearing and degraded habitat-resulting from climate change, urbanization, agricultural intensification, and international trade-as the leading driver of bird declines worldwide. In a note of hope, the authors cite a 2020 study indicating that restoring just 5% of habitat in priority areas around the world could avert 60% of likely extinctions.

Lead author Alexander Lees, a research associate at the Cormell Lab, also points to the need for substantial changes in human behavior to prevent further losses. "Loss and degradation of habitat is often driven by demand for resources," says Lees. "We need to better consider how commodity flows such as beef, oil, and seed crops can contribute to biodiversity loss and try to reduce the human footprint on the natural world."

Migratory (迁徙的) birds are declining globally because of the way that humans have changed the landscape over recent decades — according to new research from the University of East Anglia (UEA).

A new study published today reveals that population declines have been greatest among species that migrate to areas with more human infrastructure — roads, buildings, power lines, wind turbines (涡轮机) — as well as more population and hunting levels.

Dr. James Gilroy, from UEA's School of Environmental Sciences, said, "We know that migratory birds are in greater decline than non-migratory species, but it's not clear why. We want to find out where in their life cycles these migratory species are most exposed to human impacts."

The research team identified 16 human-induced threats to migratory birds, including infrastructure associated with bird disturbance and impacts, transformation of land from natural habitat to human land use, and climate change. Advances in satellite imagery allowed the team to map each of the 16 threats across Europe, Africa and Western Asia. The team also created the first ever large-scale map of hunting pressure across the region. A total of 103 species of migrating birds were studied, including many rapidly declining species like the turtle dove and the common cuckoo, using large-scale datasets. The team calculated threat scores for factors such as habitat loss and climate change, across breeding locations, as well as non-breeding ranges. They then explored the relationships between these threat scores and bird population trends calculated from 1985 to 2018 by the Pan-European Common Bird Monitoring Scheme (PECBMS).

Dr. Aldina Franco, also from UEA's School of Environmental Sciences, said, "Our findings are important because we need to understand where declining species are being most impacted by humans across their seasonal migrations. Locating where birds are most exposed to these threats could help us target conservation actions."

The Amazon rainforest, is as undisturbed a place as most people can imagine, but even there, the effects of a changing climate are playing out. Now, research suggests that many of the region's most sensitive bird species are starting to evolve in response to warming.

Birds are often considered sentinel（哨兵）species-meaning that they indicate the overall health of an ecosystem-so scientists are particularly interested in how they're responding to climate change. In general, the news has not been good. For instance, a 2019 report by the National Audubon Society found that more than two-thirds of North America's bird species will be in danger of extinction by 2100 if warming trends continue on their current course.

For the new study, researchers collected the biggest dataset so far on the Amazon's resident birds, representing 77 non-migratory species and lasting the 40 years from 1979 to 2019. During the study period, the average temperature in the region rose, while the amount of rainfall declined, making for a hotter, dryer climate overall. According to the report on November 12 in the journal Science Advances, 36 species have lost substantial weight, as much as 2 percent of their body weight per decade since 1980. Meanwhile, all the species showed some decrease in average body mass, while a third grew longer wings.

Because of the study's long time series and large sample sizes, the authors were able to show the morphological（形态学的）effects of climate change on resident birds. However, the researchers themselves are unsure and wonder what advantage the wing length changes give the birds, but suppose smaller birds may have an easier time keeping cool. In general, smaller animals have a larger rate of surface area to body size, so they dissipate more heat faster than a bigger animal. Less available food, such as fruit or insects, in dryer weather might lead to smaller body size.

    Feeding birds is a popular way to watch wildlife. But experts say it might put wild birds at risk.

    Feeding birds is not necessary for their survival except in extreme weather conditions. Feeders(喂食器)can definitely help birds get through that kind of weather. But most birds eat insects and show little interest in bird feeders. For those birds, we can grow native plants in a natural environment. Birds which are fond of eating seeds will be more likely to come to feeders if there is some cover nearby. This lets them feed and then fly to protective areas, such as in trees.

    The most common mistake people make with their bird feeders is that they put feeders in places where birds are easily frightened by passers-by, risk being hurt by cats, or risk flying into windows.

    So set up a bird feeder at least one meter away from a window. That way, if a bird gets frightened, it won't get killed when it hits the glass. Owners of cats should keep them inside home so they can't hurt the birds.

    Some birds are more aggressive at feeders. They eat a lot and do not leave much food for other birds. A solution is to put the food in more than one place by using different kinds of seeds or fruits. This can also increase the number and diversity of birds in your neighborhood. But don't feed wild birds anything salty, like potato chips, or food that could choke them, like bread.

    Pay attention to food quality and freshness. Unprotected food left too long in feeders will turn moldy(发霉), which can kill wildlife.

    Another word of advice: Always provide a supply of clean water for birds, but use care when looking for the right birdbath. If the birdbaths are too deep for birds, putting a few large stones in the water can give the birds a place to sit.

Animals can move from place to place, but plants cannot. When an animal is under attack, it can run away or fight back. Plants certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.

Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines(刺)that discourage grass­eating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.

Some plants, such as the oak tree, have thick and hard leaves that are difficult for animals to eat. Some grasses may contain a sandy material；eating such grasses wears down the animal's teeth.

Many plants also have chemical defenses, some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar(毛虫)bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.

Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly(多刺的)leaves, and each prickle contains poisonous venom(毒液)．A single experience with this kind of plant will teach an animal to stay away from it in the future.

Dogs Trained to Find Endangered Animals

Many dogs are very hard - working animals. They have been helping people for thousands of years. Dogs protect our homes. They help people with disabilities. They team up with rescue workers in search -and - rescue operations. And now, dogs can add another job to their resumes—finding endangered animals! The official title for this kind of work is conservation detection dog.

Luke Edwards is a dog owner and trainer. He is training two border collies (边境牧羊犬), named Rubble and Uda, to become conservation detection dogs.

He says that border collies are good for this kind of work because they have a great, sense of smell. The dogs also have great stamina—the mental and physical strength to work long hours.

Recently, the dogs went on their most difficult job yet - finding the Baw Baw frog. This frog is one of Australia's most endangered animals.

The work is difficult mainly because of the search area. Just to get to the place where the frogs live. the dogs and their trainers must walk far distances through alpine (高山) forests. It is difficult but important work.

A deadly fungus (真菌) has killed nearly all of Australia's Baw Baw frogs. In fact, scientists say these creatures could disappear in the next five to ten years.

Zoos Victoria is a group set up to protect wildlife. Conservation experts there claim that since 1980 the deadly fungus has killed off 98 percent of the Baw Baw frogs.

So. Zoos Victoria is trying to save the frogs. Experts there raise them and have them reproduce. They call it their captive breeding program.

Bananas and apples continue to ripen after being picked. Cherries and grapes do not. The difference between climacteric (后熟的) and non-climacteric fruits matters to fruit growers and greengrocers, who must ensures their products are in excellent condition when arriving at the marketplace. But how those differences originally came about remains unclear.

In a paper in Biology Letters, Fukano Yuya and Tachiki Yuuya of the University of Tokyo offer a suggestion. Fruits, they observe, exist to solve a problem faced by all plants - how best to spread their progeny around. Wrapping their seeds in a sugary flesh, to provide a tasty meal, serves as a way to got animals to do this for them. They do, however, need to ensure their fruits favour the animals most likely to do the distributing. They propose that climacterism or non-climacterism is a way to achieve this. If ground-living animals are the main distributors, then the continuing ripening of fallen fruit is beneficial. If, by contrast, those distributors are tree-living or flying animals, which can feed on unfallen fruit, then non-climacteric fruits will do well.

To test their idea, the two researchers combed through 276 papers about 80 sorts of fruits. They discovered 35 of these fruits were eaten by both groups of animals. But of those where one group or the other were the dominant consumers, 15 of the 19 eaten mainly by ground-living animals were climacteric.

Their assumption is strengthened by other evidence. They point out non-climacteric fruits tend to have vivid colors which may help them stand out amid the leaves, advertising their presence. Climacteric fruits are generally better hidden, making them harder to spot until they have fallen to the ground.

The blue whale is the largest animal that has ever lived. It can reach 30 meters long and weigh as much as 181,000 kilograms. The animal's heart alone weighs more than a fully grown cow. For the first time ever, scientists have recorded its heart rate.

Stanford University ocean biologist Jeremy Goldbogen led the study of the blue whaled heart rate. To get this reading, the researchers attached an electrocardiogram device(心电图设备) to the body of a blue whale. They recorded nine hours of information on a 22-meter-long male from the Pacific Ocean off the coast of California. The data did not come easily.

"First, we have to find a blue whale, which can be very arduous," Goldbogen said, because these animals live across massive areas of the open ocean. But, with years of research experience and some luck, he explained, the team was able to position a small boat along the whalers left side.

Then, the researchers connected a special recording device to a very long pole. As the whale surfaced to breathe, they quickly put the device as near to the animal's heart as possible. The small device had four suction cups(吸盘) on it, permitting it to remain on the whale for several hours.

They found out that when the blue whale dived for food, its heart rate dropped to between 4 to 8 beats per minute—with the lowest being two beats per minute. At the bottom of the hunting dive, the whale's heart rate rose to about 2. 5 times the minimum and then decreased again. Once the whale got its fill and began to surface, the heart rate increased. The highest heart rate — 25 to 37 beats per minute — occurred after the whale came out of the water for air. The findings are different from what scientists have already known — larger animals have slower heart rates. Therefore, they believe that such research helps scientists understand how huge animals operate.