Scientists have long had it in their mind to make a robot lizard (蜥蜴). They began with finding out why a lizard can hang on a wall. They noticed the lizard’s toes were unique: they have suckers (吸盘), which enable it to hang on walls. They, therefore, made a robot with suckers on its hands and feet.

The robot could hang on the wall but fell off when climbing. So, they went on researching. 6 years ago, scientists discovered that suckers only were not enough. It is the bristles (刚毛) on each foot that adds friction (摩擦) and static adsorption (静电吸附力) that makes a lizard move on the smooth wall easily without falling down.

Then scientists made great efforts to fix thick bristles to the robot’s hands and feet. However, the effect was not satisfactory. The robot still couldn’t attach itself firmly to the wall.

Scientists got puzzled: how on earth can the lizard climb on an extremely smooth wall or even on a ceiling without dropping off?

An accidental finding inspired them. One day a scientist happened to see a cat attack a lizard and bite off its tail. The lizard broke away from the cat’s teeth and threw itself on a wall to escape, only to fall off heavily on the ground. The scientist wondered: is it the tail that plays an important role in its travelling on the wall? He caught some lizards for an experiment. The result proved his assumption: a tailless lizard has no trouble walking on an ordinary wall but can’t on a smooth one. A further study showed the lizard’s tail can prevent it falling over backward and, what’s more, that the tail acts as an additional leg while one of the lizard’s legs leaves the wall, which is always the case while it is walking on the wall.

Thus, Tailbot, a super tailed robot, is born.

For centuries, fishers in Narrangansett have fished in the waters of the northwestern Atlantic for herrings (鲱鱼). But as climate change warms the world’s seas, the herrings are disappearing at the southern end of their range and turning up more often at its northern edges. A study shows that concentrations of marine (海洋的) species populations have been shifting away from the equator (赤道) and toward the poles during the course of the past century. These movements could wreak havoc on food webs and endanger the livelihoods (生计) of fishers.

The tropical (热带的) water at the equator is well-known for having the richest diversity of marine life on Earth. The number of marine species naturally decreases gradually as you head towards the poles. Ecologists have assumed this global pattern has remained stable over recent centuries until now. Our recent study found the ocean around the equator has already become too hot for many species to survive, and that global warming is responsible. And as species flee to cooler water towards the poles, it’s likely to have deep impacts on marine ecosystems.

Losing species in tropical ecosystems means ecological adaptation to environmental changes is reduced, potentially damage ecosystem persistence. In subtropical ecosystems, species richness is increasing. This means there’ll be species invaders, and new competitive relationships. This could result in ecosystem collapse in which species go extinct and ecosystem services (such as food supplies) are permanently changed.

One way is to reduce our emissions aggressively. Other opportunities could also help safeguard biodiversity and hopefully minimize the worst impacts of it shifting away from the equator. Designing climate-smart reserves could further protect biodiversity from future changes. For example, reserves for marine life could be placed where the climate will be stable over the foreseeable future. We should take action without delay.

Our planet is rich in life.Tigers and turtles,bats and bees,gnats and gnus,crabs and crabgrass-the list seems endless.We have named more than 1.5 million species,and suspect that millions more remain undiscovered.Scientists call this mind-boggling variety of life biodiversity.With so many species,it is surprising to realise that so many are in danger of becoming extinct.

Extinct species are plants and animals that once lived on Earth,but no longer live anywhere in the world.Endangered species are those most in danger of extinction.Even large populations of animals can be at risk.Passenger pigeons once darkened the skies of the US.Over time,habitat destruction and hunting decreased the population of these birds.The last one died alone at the Cincinnati Zoo in 1914.

Dinosaurs,dodos and passenger pigeons are all extinct.Extinction used to happen naturally,but in modern times,people have pushed wildlife to the brink much more quickly than ever before.We are losing wildlife very rapidly!

After realising this severe situation,many countries and international organisations have carried out rules and principles to protect endangered animals.The US Endangered Species Act of 1973,for example,was passed to protect threatened wildlife and habitats so they don't go the way of the dodo.

So why do animals become endangered?The main reason is the loss of habitats.Habitat destruction can make it extremely hard for wildlife to survive.However,as people learn to take better care of plants and animals as well as their habitats,endangered and threatened species may begin to make a comeback.In fact,many species such as bald eagles already have.