墨尔本PTE素材库——Color-Changing Skin Aids Climate Control and Communication

墨尔本PTE素材库——Color-Changing Skin Aids Climate Control and Communication

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这段材料讲述了墨尔本大学的生物学家们关于松狮蜥皮肤变色的研究。文章内容并不算长，信息量却很丰富，但是信息点也比较集中。

澳大利亚语言学院会定期整理一些PTE的素材库，旨在用这些与Question Criteria高度契合的素材，让大家在平日复习的时候有题可练，有素材可学习。光靠PTE官方所给出的那些复习材料，想要大幅度的提升自身英语水平，其实是远远不够的。这段材料就非常适合用来练习Re-tell Lecture，是一篇很好的关于动物科学的听力材料，也非常适用于练习Repeat Sentence和定位关键信息。大家听完之后可以尝试总结科学家们是如何研究松狮蜥的皮肤变色行为的，以及松狮蜥的皮肤变色有哪些特点及作用。

【key Vocabulary】

Evolve: 发展，进化

Coloration: 着色，染色

Jaguar: 捷豹

Slink: 潜逃，溜走

Undetected: 未被发现的，未被检测的

Mottle: 斑点，杂色

Pigmentation: 染色，色素淀积

Bark: 树皮，深青棕色

Chromatophore: 色素提，叶绿体

Camouflage: 伪装，掩饰

Species: 物种，种类

Regulation: 管理，规则，校准

Soak up: 吸收

Thermal: 热的，热量的

Lizard: 蜥蜴

Signalling: 信号传输法

Simultaneous: 同时的，同时发生的

Full Transcript

Bearded dragons modify their colors for camouflage or to maintain their body temperature, or to communicate with other dragons. Jason G. Goldman reports.

Various animals evolved coloration that keeps them hidden. A jaguar‘s patterns help it slink undetected across the sun-dappled rainforest floor. The mottled pigmentation on the wings of some let them rest on tree bark undisturbed. And then there are animals that can quickly change their appearance—for example, the Central Bearded Dragon.

This two-foot-long lizard lives in the more arid parts of Australia.

“They can change color really quickly, just in a matter of seconds or minutes.”

University of Melbourne biologist Katie Smith.

“And they do this by moving pigments within specialized skin cells called chromatophores.”

Bearded dragons modify their colors for camouflage, or to maintain their body temperature, or to communicate with other dragons. Smith wanted to know how they meet all those needs with the same tool kit.

So she and her team rounded up twelve bearded dragons and put them through a series of tests before releasing them back into the wild. They found that when the dragons want to communicate with other members of their species, they change the colors on their neck.

“This is actually one of the reasons they’re called bearded dragons—because they look like they have a really serious five o’clock shadow.”

Changes to their backs were for temperature regulation. Shifting to yellow lets them to cool off during extreme heat, while darker greys allow them to soak up more heat during cooler weather.

“They actually save about, on average, 22 minutes a day at the darker colors than the lighter colors. That’s about 85 hours throughout the whole year.”

Eighty-five hours a year NOT spent out in the open and exposed to potential predators. The results were published in the Proceedings of the Royal Society: B. [Kathleen R. Smith, Viviana Cadena, John A. Endler, Warren P. Porter, Michael R. Kearney, & Devi Stuart-Fox. Colour change on different body regions provides thermal and signalling advantages in bearded dragon lizards.]

The lizards can clearly control each part of their body separately, resulting in an efficient system. Temperature regulation involves the back, which is facing the sun. Social signalling uses the neck, easily visible to another lizard they’re faced off with.

The researchers’ next task is to see what happens when the lizards have to deal with simultaneous but conflicting coloration requirements—situations that could give a bearded dragon a close shave.

—Jason G. Goldman

(Source: http://www.scientificamerican.com/podcast/episode/color-changing-skin-aids-climate-control-and-communication/)