by Paul Gabrielsen 胡德良 译
Dogs pant. Humans sweat. But how do starfish keep from overheating? At the hub of a sea creature's five arms (or more, in some species) is the central disk, which holds the animal's heart, stomach, and central nervous system. If this disk's temperature rises above 35°C (such as at low tide, when the animal may be isolated from cool ocean water) the starfish dies. To figure out how the animal stays cool, scientists collected 70 ochre starfish ( Pisaster ochraceus) from the California coast and placed them under heat lamps to simulate potentially lethal low tide heat exposure, at temperatures ranging from 26°C to 42° C. About one-third of the starfish died when their central disk temperatures reached 35°C, the team reports online today in The Journal of Experimental Biology. Researchers found that the arms of surviving starfish were a few degrees warmer than the disk, as warm as 39°, suggesting that the animals shunted heat into their extremities. The strategy is not without a cost, however. In the days following the experiment, 16 of the surviving starfish severed their own heat-damaged arms, which are costly to regrow. | 狗喘气,人出汗。可是,海星是如何使自己免于过热的呢?海星五臂(一些品种拥有更多的星臂)的中心部位,拥有中心盘,中心盘内有心脏、胃、和中枢神经系统。如果中心盘的温度达到35°C以上时(如遇到低潮时,海星可能会与凉爽海水隔离开来),海星就会死亡。为了搞清海星是如何保持清凉的,科学家们从加州海岸搜集了70只赭色海星(Pisaster ochraceus),并且将它们置于热灯之下,模拟在可能致命的低潮中所处于的热环境,这种环境的温度从26°C 到 42° C不等。今天,研究小组在《实验生物学杂志》在线版上报道说:当中心盘的温度达到35°C时,大约有三分之一的海星死去。研究人员发现:在存活下来的海星中,星臂比中心盘高出了几度,达到39°C,说明海星将温度转移到星臂上。然而,这种转移机制并非没有代价的:在继续进行这项实验的日子里,16只存活下来的海星截断了自己遭到热损害的星臂,要想重新长出来,代价沉重哦! |
译自:美国《科学》杂志网站(29 May 2013, 6:00 PM)
原著:Paul Gabrielsen
小妹如此多娇(图) | 古典旗袍美女欣赏(组图) |
休闲游戏—斗地主(游戏) | 周末过一把美人关(小游戏) |
龟是如何长出龟甲的?(图) | 猴子的微笑也会“传染”(图) |
入侵蜗牛利用奇特毒素保护下一代(图) | 解释公鸡打鸣(图) |
延时成像术:预测胎儿活产率(图) | 食肉甲虫大揭秘(图) |
抚养后代之后,蜜蜂老化加速(图) | 蝴蝶长寿之谜(图) |
评论