汉硕考研论坛_汉语国际教育考研论坛_汉硕考研网(ziyuekaoyan.com)

标题: 每日外刊 | 自然界的“绝命毒师”:毒蛇咬人的惊人秘密 [打印本页]

作者: 子曰汉硕刘老师    时间: 2021-12-18 17:12
标题: 每日外刊 | 自然界的“绝命毒师”:毒蛇咬人的惊人秘密
背景知识

毒蛇的起源颇有争议,有的科学家认为,蛇来源于蜥蜴一支,而这一部分的蜥蜴和蛇共同组成一个分类:有毒类。这一部分的蜥蜴和蛇中,一部分渐渐失去毒素,譬如鬣蜥和森蚺。而另外一部分的蛇和蜥蜴保留着毒素,并将其毒性发挥到了极致,譬如毒蜥和蝰蛇。而另一部分科学家则认为,毒素在爬行动物中的运用是趋同进化的结果,也就是说不同蛇类和蜥蜴的祖先,为了相似的目的,而分别进化出不同的毒素。

正文阅读

The Surprising Secret of Snakes’ Venomous Bites
自然界的“绝命毒师”:毒蛇咬人的惊人秘密

The world hosts hundreds of wildly different venomous snake species, from brightly banded coral snakes to camouflaged cottonmouths. But somehow even distantly related species independently evolved specialized fangs with venom-carrying grooves—a longtime puzzle spurring new research into how this could have happened. The answer, says Flinders University herpetologist Alessandro Palci, has been hiding inside the serpents' mouths all along.

世界上有数百种截然不同的毒蛇,从条纹鲜艳的珊瑚蛇到伪装的水腹蛇。但不知何故,即使是远亲物种也独立进化出了带有毒液凹槽的特殊毒牙——这是长期的未解之谜,促使人们对此进行新的研究。弗林德斯大学爬行动物学家亚历山德罗·帕尔奇表示,答案一直藏在蛇的嘴里。

It turns out that the teeth of most snake species, Palci and his co-authors report in the Proceedings of the Royal Society B, have a ring of tiny indentations around their bases. This pitted tooth tissue, called plicidentine, helps to anchor the teeth to the jaws. “Before our study, plicidentine was thought to be limited to only three types of lizards among living reptiles,” Palci says. In fact, the study finds, it seems to be ubiquitous in snakes.

帕尔奇和他的共同作者在《英国皇家学会学报B》上报道,事实表明,大多数蛇类的牙齿在它们的根部周围都有一圈微小的凹痕。这种凹凸不平的牙齿组织叫做折状牙齿,有助于将牙齿固定在颌骨上。帕尔奇说:“在我们的研究之前,在现存的爬行动物中,折状牙齿被认为只存在于三种蜥蜴中。”事实上,研究发现,它似乎在蛇类中无处不在。

And these dental anchors have taken on another function in venomous species, the researchers say. They used microscopic tissue sampling and micro CT scans of snake teeth to determine that in the teeth nearest a snake's venom glands, the plicidentine's folds have evolved into longer grooves that help snake venom flow from gland to tooth—and then into prey. This result suggests that modern venomous snake species did not have to start from evolutionary scratch every time they developed a deadly bite.

研究人员说,这些“牙齿锚”对有毒物种有另一种作用。他们对蛇的牙齿进行了显微组织取样和显微CT扫描,以确定在最靠近蛇毒腺的牙齿中,折状牙齿的褶皱已经进化成更长的凹槽,帮助蛇毒从腺流向牙齿,然后进入猎物。这一结果表明,现代毒蛇物种不必每次进化出致命的咬伤都从头开始。

今日单词


素材来源
文本选自:Scientific American(科学美国人)
作者:Aurelien Breeden, Constant Méheut and Norimitsu Onishi
原文发布时间:28 Nov. 2021

每日美句
No matter how bad your heart has been broken, the world doesn’t stop for your grief. The sun comes right back up the next day.
不管你有多痛苦,这个世界都不会为你停止转动。太阳依旧照样升起。


【码上添加学姐获取最新考研资讯】

微信号 :18520569495
新浪微博:@汉硕考研院
汉硕考研QQ交流群:1063353993






欢迎光临 汉硕考研论坛_汉语国际教育考研论坛_汉硕考研网(ziyuekaoyan.com) (http://www.ziyuekaoyan.com/) Powered by Discuz! X3.5