Since English biologist Charles Darwin (1809 –1882) published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still the subject of speculation, and scientists can still only make educated guesses at certain things.

One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

Romer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land. Romer thought that tidal pools might have led to fish gaining limbs.

Romer called these earliest four-footed animals “tetrapods” (四足动物). Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, on Feb 15 that by using computer software, her team had managed to link Romer’s theory to places where fossil deposits (化石沉积) of the earliest tetrapods were found.

According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained the UK’s University of Bangor ocean scientist Mattias Green. As he told Science: “After a few days in these pools, you become food or you run out of food … the fish that had large limbs had an advantage because they could flip (空翻) themselves back in the water”.

As is often the case, however, there are others who find the theory less convincing. Cambridge University paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It’s only one of many ideas for the origin of land-dwelling (陆地栖息的) tetrapods, any or all of which may have been a part of the answer,” she said.

Scientists have discovered an astonishing number of Antarctic blue whales in the waters off the coast of South Georgia, an island in the South Atlantic Ocean, suggesting decades of conservation efforts are paying off.

During a 23-day survey, a team of researchers from the British Antarctic Survey(BAS) counted 55 animals. Dr. Trevor Branch, a scientist from the University of Washington, who specializes in studying blue whales, said the number was truly amazing.

In the last century, Antarctic blue whales were nearly hunted to extinction for their blubber, a thick layer of fat that marine animals have under their skin to keep their bodies warm. Hunters used the blubber for oil to use in products like soap or fuel for oil lamps. Around South Australia, more than 33000 whales are believed to have been killed. A hunting ban was introduced in 1966, but by that time the whales were critically endangered. In 2018 there were reported to be only around 3000 Antarctic blue whales left.

These sightings by the BAS team, helped by scientists from the University of Auckland in New Zealand, are a positive sign that the population is increasing.

“In a period of 40 or 50 years, I only had records for two sightings of blue whales around South Georgia,” Dr. Branch told the reporter. “So to go from basically nothing to 55 in one year is astonishing.” The cold water around South Georgia has always been popular with whales because it is crowded with krill, tiny shrimp-like creatures that are the whales’ favorite food.

The high count was so unusual that other scientists wondered whether it was a one-off, perhaps caused by usually high number of krill temporarily attracting whales from other areas. However, Dr. Jennifer Jackson from BAS says the quantity of krill was no different from other years. She’s confident the population growth shown in the recordings is real and down to the protection that the whales now have. This remains to be seen, but it is highly suggested that when the next assessment is released, most likely at the end of 2021, it could show a further increase in the number of Antarctic blue whales. With the comeback of the whale, this could be an inspiration for environmental campaigns that still have progress to make.

Many of us enjoy watching animals in the wild. They usually make us pleased, cheer us up and, sometimes, even make us frightened. But do you know what they can teach us? Wild geese (鹅), for example, teach a very good lesson about teamwork.

In fall, Canada wild geese fly south to get away from Canada’s cold winter weather. They lift off in no order. Yet very quickly they form a V-shape, with one bird leading the flock (鸟群). Scientists have discovered that wild geese flying in a V-shape can help them to save energy. In this way, they can fly 70 percent farther without rest than those flying alone.

What can human learn from this?

Be cooperative. We have found that wild geese make sound in flight to encourage those that have fallen behind to keep up with the speed. Team members should regularly communicate with each other while working towards a common goal.

Set a good example. When wild geese are on the ground, if something frightens the leader, it might fly off. So does the flock. But if the leader stays calm, the flock will do the same. Wild geese and people usually emulate their leaders. When leading, we must remember that our actions and feelings will be passed on to our followers.

Whether it is in our personal lives or our work, we need other people. We are encouraged by their enthusiasm and energy. If we face the difficulties alone, the risks are greater. Like wild geese, when we work together, our burdens are lighter.