| A. selected B. distinctive C. signature D. odds AB. domestication AC. decided AD. individuals BC. tamest BD. conflicted CD. mixed ABC. develop |
If you see a house cat, the
As it turns out, this story started about 10,000 years ago, when humans and cats
This
“As humans became farmers and started staying in one place, they had grain stores and waste piles” that attracted rodents, Lyons said. It was a mutually beneficial arrangement: the humans had fewer rodents to deal with and the cats got an easy meal.
The wild, undomesticated ancestor species of house cats, Felis silvestris, lives in Africa and Eurasia. These felines are tasty snacks as kittens and stealthy predators as adults, so
But not every F. silvestiis is born with a coat that blends into its habitat.
“Genetic mutations are occurring all the time.” Lyons said.
There isn’t much evidence to indicate why early cat people chose the individuals they did, but Lyons said the range of coats seen on modern domestic cats shows that our agrarian ancestors favored cats with markings that would have
In its native mixed forest or scrub desert environment, a cat with stark white paws would have stood out to predators and prey.
When humans started taking an interest in cats, these white paws would have stood out to them, too. “There were probably people saying, ‘I particularly like that kitten because it has white feet . Let’s make sure it survives’”, Lyons said.
Humans probably also
These
Then, those cells slowly migrate down and around the body. If those waves of cells move far enough to meet each other on the cat’s front side, the embryo will be born a solid-colored kitten, such as an all-black or all-orange cat. Felines
So, the next time you see a kitty wearing white socks, you’ll know that this
| A. attacks B. plains C. reserves D. harmony E. threat F. exists |
Herds of Tibetan antelopes used to live on the
| A. army B. available C. displayed D. reserves E. straight F. inserted G. additional H. advocates I. initiative J. proven K. existing |
A new way to reduce poaching
Researchers are working on a pilot program backed by Russia’s Rosatom Corp to inject rhino horns (犀牛角) with radioactive material, a strategy that could discourage consumption and make it easier to detect illegal trade.
Poachers (偷猎者) killed 394 rhinos in South Africa for their horns last year, government data shows, with public and private game
Thousands of
Known as The Rhisotope Project, the new anti-poaching
“If we make it radioactive, these people will be hesitant to buy it,” Larkin said. “We’re pushing on the whole supply chain.”
Besides Russia’s state-owned nuclear company, the University of Witwatersrand, scientists and private rhino owners are involved in the project. If the method is
“Once we have developed the whole project and got to the point where we completed the proof of concept, then we will be making this whole idea
| A. mineB. criteriaC. catalogedD. candidateE. delay F. anticipatingG. comprisedH. perceivingI. initiativeJ. compounds K. unfavorable |
What Lies Beneath
“Earth” has always been an odd choice of name for the third planet from the Sun. After all, an alien (外星人) examining it through a telescope would note that two-thirds of its surface is
A new
The attempt is happening now for two reasons. One is that, the longer scientists
The second one is technological. Marine biologists discover about 2,000 new species a year, a rate hardly changed since Darwin’s day. Ocean Census is
Exactly what the new effort might turn up, of course, is impossible to forecast. But history suggests it will be fruitful. Half a century ago scientists detected hot openings on the sea bed that were home to organisms living happily in conditions that, until then, had been thought
More practical benefits can’t be ignored. Many drugs, for example, come originally from biological
To help make use of its data, Ocean Census plans to make it attainable to scientists and the public without charge, who will be able to search it for anything valuable or unexpected.
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