SSS 2008-02-26
时间：2018-12-24 作者：英语课 分类：Scientific American(二)月
This is Scientific American’s 60-Second Science. I am Karen Hopkin. This will just take a minute.
Being a big fish in a small pond is more likely to get you noticed. That’s good news if you are, say, the best pitcher 1 in your little league division, but it’s not so good if you're an actual fish. Because bigger fishes are the ones that tend to get caught. Not only is that bad news for the fish, but it may be bad for the whole fish population. Or so say scientists from Australia and Canada in the online edition of the proceedings 2 of the National Academy of Sciences. They find that fishing for the largest individuals targets the fastest growers, leaving behind their slower growing counterparts. That means that current fishing practices may favor the evolution of slower growing fish.The scientists stocked two small lakes in British Columbia with two strains of rainbow trout 3. One that grows quickly and is more aggressive in chasing down food. And the other that grows slowly and tends to be more cautious.They then used commercial gillnets to fish the lakes and found that they bagged the bolder fish three times faster than the shy ones which were left behind to multiply. So we could inadvertently be breeding fearful small fry that are nearly impossible to catch, which will make them hard-to-see food.
Thank for the minute for Scientific American’s 60-Second Science. I am Karen Hopkin.
- He poured the milk out of the pitcher.他从大罐中倒出牛奶。
- Any pitcher is liable to crack during a tight game.任何投手在紧张的比赛中都可能会失常。
- He was released on bail pending committal proceedings. 他交保获释正在候审。
- to initiate legal proceedings against sb 对某人提起诉讼