Why are fish so smart? Because they swim in schools! Even though a school’s out for the summer, most fish are still swimming in schools wherever they may be. Let’s take a closer look at why most fish tend to stick together.

       When fish stay together for social reasons, biologists say they are “shoaling”. If they also swim together in the same direction, they are “schooling”. So why do fish shoal and school together? The main reason appears to be that there’s safety in numbers.

       Staying together in schools helps to protect fish from their enemies. While a predator(食肉动物) might easily grab a fish by itself, it’s much harder for a predator to single out a victim if a fish is surrounded by hundreds of his closest friends.

       Hanging out in schools also has a few other benefits. Scientists think that swimming close together may reduce friction(摩擦) in the water and make it easier for fish to swim and conserve energy. When it’s time to eat, it’s also easier to find food as a group. A lone fish might be able to find a meal on his own. But having hundreds of sets of eyes and noses on the prowl for food is even better.

       Not all fish shoal or school, though. Scientists estimate that at least 80 percent of all fish will school at some time in their lives. Some fish--often larger species--choose to live solitary(孤独的)lives.

       If fish do decide to school, exactly how many fish does it take to be a school? While there’s no magic number that equals a school, there would usually need to be at least five or more fish to be considered a school. In the wild, though, fish schools can be huge. In large bodies of water, schools of fish numbering in hundreds or even thousands are not uncommon.

       If you’ve ever seen a huge school of fish swimming together in unison, you may have wondered how they keep from swimming into each other. Scientists believe fish use a combination of some of their senses to keep track of the movements of the fish around them* Having their eyes on the sides of their heads helps fish to see what’s going on around them easily. Sight isn’t the only tool fish use, though. They also use hearing and even their sense of smell to stay with the group.

Some people are like homing pigeons: Drop them off anywhere, and they’ll find their way around. Other people, though, can’t tell when they’re holding a map upside down. Are the directionally challenged just bad learners?

    Not all of your navigational skills are learned. There’s evidence that your sense of direction is innate. Your brain has special navigational neurons—head-direction cells, place cells, and grid cells—and they help program your internal GPS when you’re just a baby.

    In 2010, scientists carried out an experiment to study baby rats’ neural activity in their brains. Although the rats were newborns, the researchers discovered that their head-direction cells (which help them recognize the direction they’re facing) were fully mature. The rats, it seemed, were born with a sense of direction. And they hadn’t even opened their eyes yet!

    Humans, of course, are not rats. But the hippocampus—the brain region responsible for navigation—is similar in most mammals. If the rat’s compass develops this way, then it’s likely that a human’s compass does, too.

    If we’re born with a sense of direction, then why are some people so good at getting lost? The scientists found that the two other cells—place and grid cells—developed within the first month. Place cells are thought to help us form a mental map, while grid cells help us navigate new and unfamiliar places. The two cells interact—and that’s where the trouble might be.

    People who took part in a 2013 study played a video game that required them to travel quickly between different places. Monitoring their brains, the scientists found that grid cells helped the gamers keep track of where they were—even without landmarks. According to researcher Michael Kahan, differences in how grid cells work may help explain why some people have a better sense of direction than others.

The Alice Ferguson Foundation is a non-profit group that works to improve the environment by building relationships between people and nature. The foundation is based in the state of Maryland. It was created more than 50 years ago. It teaches people ways to protect the environment.

  At the end of the year, it designs events to help children celebrate Christmas without increasing the amount of waste they create. Hanna Seligmann works for the foundation. “So let’s figure out what is in our bag of trash.” She shows adults and children how to reduce waste during the holiday gift-giving season. “You can sort it as a cardboard item or you can sort it as a plastic item.” “We encourage using things that are already in your house like newspaper, old magazines, using a gift within a gift.” Urging people to recycle is important in the Washington, D.C., area, because Potomac River, one of the most famous rivers in the country lies there.

“Over time we realized that really just doing trash cleanups was the symptom of the problem, not getting to the root cause. And so it was just a little over a decade ago that we started the initiative (倡议)itself.” says Seligman.

The Trash Free Potomac Watershed Initiative is an effort by the Alice Ferguson Foundation to support clean agricultural methods. It includes educational programs teaching children about the kinds of pollution that can enter the watershed.

One activity is called the Trash Timeline Game. It teaches children that the things they throw away do not decompose, at the same rate. For example, paper dissolves in about four weeks. An apple core may take two months to rot. A metal can take up to 100 years.

Based on new analysis, we are rapidly approaching major climate change and the effects on society and the environment could be quite severe. Geographers predict that within the next eighty years, current world climate zones could shift and some could completely disappear. Polar regions will get colder while tropical regions will get even hotter, forcing animals to migrate (迁徙) north.

Climate changes like these could lead to the spread of diseases. Tropical storms and hurricanes will not only increase but may also become more intense. If the changes come too quickly, animal and plant species may not be able to adapt fast enough and could disappear.

According to Science Daily, a new study predicts that by the year 2100, many of today’s familiar climates will be replaced by climates unknown in today’s world. It is urgent that we reduce the risks of these far-reaching consequences for the whole world. The planet itself has been showing signs of change. In 2004, a serious tsunami created by a major earthquake killed thousands in Sumatra and in 2008, thousands died in China because of another severe earthquake. Egypt was hit in 2009 with a major earthquake and Haiti was devastated in 2010 by yet another massive earthquake.

Within just the last few months, new reports from around the world have been coming in and most agree that our climate situation is much worse than previously thought. At this point, it doesn’t matter what is causing it, but rather, what can be done about it. What’s more, our world is getting more and more unstable every year. There is war and threat of war everywhere. Natural disasters are becoming more frequent and serious.

However, other planets are experiencing global warming as well as our own and some scientists believe there may be some connection between this. No one knows anything for sure at this point because there is simply not enough data.

Rising levels of carbon dioxide in the atmosphere are a major cause of climate change, and now a new study has confirmed that atmospheric is also affecting the ocean chemistry and potentially harming sea life.

Montana State University scientist Robert Dore has been researching the water in the Pacific Ocean for almost two decades. “We've been going to the same spot in the Pacific Ocean, and we try and characterize long­term change in the open ocean environment. And one of the key things that we measure is levels. And we've been able to record this increasing quantity of atmospheric into the ocean.”

Scientists expected that as atmospheric increased, more and more of the carbon dioxide would be absorbed into the ocean, affecting the chemical balance of the sea water, with a potentially harmful impact on shellfish and coral in particular.

“As carbon dioxide dissolves in the water, or seawater in this case, it forms a weak acid, carbonic acid，” Dore explains. “And therefore, as the concentration of in the atmosphere goes up and that exchanges with the surface seawater, it drives the PH down, and makes it more acidic.”

The seawater samples Dore and his colleagues have analyzed confirm what the theory predicts.

The effect was particular striking at about 250 meters down, and again at 500 meters. Dore and his colleagues came up with two possible explanations. It could be that surface water picked up and then moved to those depths. Or there could be a biological explanation.

“It's important to realize that the oceans are really becoming acidic. And it can have negative impacts on a whole variety of sea life from fish to coral. It's potentially catastrophic.”

a．Sea life is endangered.

b． goes into the surface water.

c．The ocean chemistry is affected.

d． decreases the PH and makes the seawater more acidic.

e. levels in the atmosphere go up.

Across the United States, universities and colleges have been looking to become more sustainable (可持续发展的) and more than 600 schools have already planned to become eco-friendly. The EcoDorm, home to 36 students at Warren Wilson College in Swannanoa, was designed to be sustainable from top to bottom, or in this case, from its rainwater-collection system to its garden. The dormitory is bringing new meaning to the concept of living “green” at college.

At Warren Wilson College, a biological science school with fewer than 1,000 students, the sustainability drive came from the student body. The EcoDorm concept was presented ten years ago by two students; a planning committee firstly suggested using building materials like corncob. Although the architects disagreed with the idea, they came up with other creative solutions: Wood siding was taken from the trees grown in the school yard that were suffering from a disease, and rainwater was collected in an old railway car and pumped back into the house to clean the toilets.

All in all, the dorm uses nearly two-thirds less electricity than a similar-sized traditional building world. But even the most sustainable homes need continued efforts from its livers. And in the case of EcoDorm, students live by their words. Most also take advantage of the dorm’s bio-garden, planting and harvesting fruits and vegetables. “I didn’t have to worry about paper towels being wasted or feel bad about drying my clothes outside,” Jeremy Lekich, the dorm’s gardener, said. “Basically, it has made my life easier.”

UFO stands for "unidentified flying object". Many people reported having seen UFOs in the sky. A lot of countries tried to research them and in 1952 they got the name of UFO.

There were several reports published in the 19th century which were related to UFOs. Denison Daily News in its report of 25th January, 1878 wrote that a farmer, Martin, saw a flying object in the sky and it was just like a plate. This was the first time that the word plate had been related to the UFOs.

The first reports on UFOs came during World War II. In 1947 pilot Kenneth Arnold said while he was flying near the Mount Rainer he saw a very bright object in the sky. He said that it was like a plate too. The information given by Kenneth got lots of attention from the media and people.

Several research organizations gave their reports on the UFOs. They showed direct or indirect physical evidence of the UFOs, and sometimes UFOs’ appearance was found on the radar (雷达) screen. Many people tried to take video tapes or photos of the UFOs as testimony. Most UFOs are in saucer shape while many UFOs are like a cigarette or a half ball.

Many films and TV shows are made about UFOs. There are two famous movies which are created on the theme of UFOs and aliens, War of the World and Star Wars. UFOs have created a new field in science which is known as Ufology (飞碟学).

When Iain Douglas-Hamilton first started studying elephants in Africa,he had to invent ways of tracking the big animals. Over the course of 40 years in the field, the zoologist learned how to fly airplanes and use some high-tech means to follow their movements. He also learned how to get out of the way fast. "I learned how to climb trees very quickly," says Dr. Douglas-Hamilton, winner of the 2010 Indianapolis Prize.

As co-founder of Save the Elephants, he has also learned to be an activist, author, and politician. When Douglas-Hamilton left Tanzania, in East Africa, in 1970 to study at Oxford University in Britain, he left behind "an elephantsˈ paradise (乐园)."But when he returned in 1972, the countryˈs national parks looked more like a war zone. Douglas-Hamilton often found more dead elephants than living ones.

Dr. Douglas-Hamilton now lives in Kenya with his wife, Oria, who co-founded Save the Elephants. Together they have written two books, "Battle for the Elephants" and " Among the Elephants".

During the height of the ivory poaching (偷猎),Douglas-Hamilton flew in small planes, helping bring back elephants in Uganda from the edge of extinction. Heˈs been repeatedly shot at and has survived plane crashes, floods and diseases. He fought for years for a worldwide ban on ivory sales, which finally took effect in 1989.

Douglas-Hamilton pioneered the scientific study of elephant social behavior. Among his discoveries: Elephants have a society controlled by female elephants and travel in families. In 2009，he worked to save a rare group of desert elephants in Mali from the worst dry weather in Maliˈs history. There have been other successes, particularly in East and Southern Africa. Douglas—Hamilton has proposed (提议) the idea of a mobile national park, where the protected land would follow elephants as they travel. No country has yet accepted it.

Even after decades of research, Douglas-Hamilton still enjoys the company of elephants. "I love to sit with them and be with them, "he says. "I have the greatest joy just to be with elephants at peace."

Owls(猫头鹰) are mysterious creatures. We often think of them as scary. They sometimes live in abandoned houses. They fly without a sound through backyards at night. In stories, they appear with ghosts. When we hear an owlˈs familiar “wh­ooo...whooo...”，it can make us feel very frightened. Owls fly silently, without even a whisper of wings moving through the air. Itˈs as though they appear out of nowhere—like ghosts on wings. Owls fly and hunt on the darkest of nights. An owlˈs night habits make it unique. Do these creatures of the night possess strange powers?

Owls possess unusual powers of sight and hearing, but they are not supernatural powers. They are natural adaptations that let them live most efficiently(高效地) at night. There is no reason to fear owls. Their habits make them helpful to humans. By hunting mice and other rodents(啮齿目动物)，owls help to keep a natural balance between plant and animal life. Without owls, there would be a large number of rodents in farmersˈ fields and storage barns.

More than 100 species of owls occupy a variety of habitats around the world. A few oceanic islands and the Antarctic have no owls. The worldˈs owls come in large, medium, small, smaller, and smallest. For example, the Eurasian eagle owl—one of the largest—has a body that is two to three feet long, with a wingspan(翼展) of up to five and one­half feet. The North American elf owl (the worldˈs smallest owl) is five to six inches long and has a wingspan that measures slightly more than one foot.

Most male and female owls of the same species look alike, although females are usually larger. In some species, the femaleˈs colors are like those of the trees or grass where she makes her nest.

Baby owls, called chicks, stay with their parents until they are about three months old. They soon find their own hunting areas, where they may stay for the rest of their lives. Some owls can live 20 years or more.

Parents are often amazed at how fast their child grows and develops. New research has determined that the ability to quantify may develop much sooner than most parents realize.

Kristy vanMarle, professor of the University of Missouri, has determined that contrary to what previous studies have shown, infants（婴儿）are able to quantify substances（物质）—like sand or water—as early as 10 months. As long as the difference between the two substances is large enough, infants will choose the larger amount, especially when it comes to food.

With the assistance of her team researchers, vanMarle tested the quantifying skills of babies by presenting them with two cups: one containing a small amount of food, and one containing a larger amount. Consistently, the babies chose the larger amount.

“Several studies throughout the last 15 years have shown that infants are very good at telling how many objects they see; however, infants don’t seem to count things like water or sand,” vanMarle said. “What we’re saying is that they can quantify substances; it’s just much harder. The infants can see how much food goes into each cup and compare that in their memories. They decide which amount is larger, and they almost always select the larger one.”

This information further refutes（驳斥）the long-held idea that babies “know nothing of the world,” vanMarle said.

“Since psychologists have begun studying infants with sensitive measures, we’ve discovered a lot of early abilities. I think for parents, it should be exciting to know that there’s somebody in there that has some fundamental and basic knowledge of the world, and that knowledge is guiding their development,” vanMarle said.

In the future, vanMarle says this kind of study could be linked to a child’s progress in math-related skills, although programs marketed to increase those abilities, such as “Baby Einstein,” still have mixed reviews when it comes to academic study.