South Biologist Researches Unique Shell Shapes of Famed Galapagos Tortoises

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2017年12月4日发布

Alice Jackson

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Dr. Ylenia Chiari，大学助理教授 biological sciences at the 十大彩票网投平台, has received international media attention with publication of her innovative research into how the different shells of the famed 加拉帕戈斯群岛的陆龟可能已经进化了.

The 《十大彩票网投平台》发表了一篇报道 last week about Chiari’s lengthy research into why Galapagos Islands tortoises evolved with predominately two different type shells, despite the species being related to each other. Also, on Thursday, the academic publication “Scientific Reports” published Chiari的研究论文.

Chiari’s ground-breaking research is capturing attention because it is the first such 研究为什么两种主要的外壳类型可能会进化. 岛上的乌龟 chain near Ecuador have intrigued scientists and the public since Charles Darwin studied their ancestors as he developed his theory of natural selection in 1835. Today, the huge and endangered tortoises, often weighing as much as 90 pounds, remain frequent 科学研究和环境问题的主题.

Her research has introduced the idea that energy exerted by the tortoises may have 让我们对它们的进化有了更多的了解.

“You have these variations in the shells of Galapagos tortoises, and people have wondered 很长一段时间为什么他们如此不同. 蛋壳是非常不同的. It’s 真的很迷人，”基亚里说.

The shape of their shells has led to them being called “domed tortoises,” or “saddleback tortoises.”  The dome shells are more rounded while the saddleback shells are flatter 颈部开口凸起. 最流行的理论推测了差异的发生 to make it easier for the tortoises to upright themselves after flipping, a frequent hazard, or because they occupied different elevation habitats, or each type adapted 为不同的饲养生态位.

Chiari, who became interested in the shell shapes while on Galapagos in 2006 for a different research project, thought it would be interesting to simply begin scientific 解释差异的基础.

“There have been all these theories, but no one had ever tested them,” Chiari said. “Now, this study is the first body of evidence to produce some data showing that maybe 它有助于进化.”

She and colleagues created 3-D animated images of 89 of the tortoises. Then, she needed to determine the center of mass for each type tortoise to compare self-righting potential. That led to measurements being made of Galapagos tortoises at the Rotterdam Zoo.

Each of two turtles at the zoo was placed on a platform with three load sensor and 被拍成三维重建吗. 一旦质心被估计出来 for the two tortoises, using the 3-D reconstructions, its position was calculated 对于每一个89个重建的炮弹. 这使得科学家们能够进行计算 乌龟在仰卧后自我矫正需要多少能量.

Before studying her data, Chiari suspected, like many others, that the shape of the saddleback shells may have evolved to make it easier for them to right themselves. To her surprise, she discovered that energy exerted by the tortoises as they righted 他们自己可能导致了差异.

“Saddleback tortoises require a higher energy input than domed species to successfully self-right. Saddleback tortoises self-right by pushing their head on the ground and 然后用脚翻转，”基亚里说. “圆顶龟依靠移动 他们的脚和头获得足够的动力来自我矫正. These traits could 已经进化到能够促进自我纠正.”

Chiari's research found that not only the higher opening of the saddleback shells provides higher range of motion for the neck, but the neck of saddleback tortoises 是不是也比圆顶长.

Chiari研究论文的第二作者产生了一个 演示两种shell类型之间区别的视频 总结了他们的发现.

Chiari said she isn’t completely surprised by the publicity her study has attracted, 但她希望这将导致更多的研究.

“People like to read and watch things about the Galapagos tortoises,” Chiari said. “此外，我们使用的方法非常酷. 然后，当你发现结果 和你期望的不太一样，这很有趣.”

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