CU Boulder geologists Lizzy 相信 和 卡尔•辛普森 win $1 million in support from W.M. 凯克基金会 to try to solve an evolutionary puzzle 和 to extend Earth’s temperature record by 2 billion years

What happened during the “Snowball Earth” period is perplexing: Just as the planet endured about 100 million years of deep freeze, with a thick layer of ice covering most of Earth 和 with low levels of atmospheric oxygen, 多细胞生命出现了. 

为什么? The prevailing scientific view is that such frigid temperatures would slow rather than speed evolution. But fossil records from 720 to 635 million years ago show an evolutionary spurt preceding the development of animals. 博彩平台推荐的两位科学家旨在帮助解决这个难题.

如果他们成功了, 它们不仅有助于解开一个进化之谜, 还将地球的温度记录延长了20亿年.

卡尔•辛普森, 博彩平台推荐的宏观进化古生物学家, has found evidence that cold seawater could have jump-started—rather than suppressed—evolution from single-celled to multicellular life forms. 但为了证明极低的温度可能会加速进化, 他需要那个时期的精确温度记录. 

Temperature records using existing methods are accurate only to 500 million years ago. 这可能会改变, 尽管:莉兹·特罗尔, 化学沉积学家, 开发了一种测量全球温度从5亿到2亿的新方法.50亿年前. 

在一起, 相信 和 辛普森 hope to test 辛普森’s hypothesis against temperature records from 相信’s novel tool, 他们最近获得了100万美元的资助 W.M. 凯克基金会 这样做.

Both the fossil record 和 calculations based on a “DNA clock”—which calculates the age of current organisms based on the rate of mutations over eons—indicate that multicellular organisms emerged during Snowball Earth. 

辛普森, who is an assistant professor of geological sciences 和 curator of invertebrate paleontology at the CU Museum of Natural History, has spent a lot of time since coming to CU Boulder trying to underst和 the connection between extreme, 漫长的寒冷和进化. He describes a breakthrough stemming from a “knuckleheaded” approach: “trying to imagine what the unicellular ancestor of an animal would have been experiencing” during Snowball Earth.

在这个“寒冷”时期, 咸而暗”时期, 赤道上可能有一公里厚的冰, 冰下的液态水会非常冷, 约零下5摄氏度(约23华氏度). 

“One thing that you learn about small organisms from a physics point of view is that they don't experience the world the same way that we do, 作为体型较大的生物体,辛普森说. 单细胞生物受海水粘度或厚度的影响.

The increase in viscosity—which increases as water temperature falls—could yield an evolutionary advantage to those single-celled organisms that clumped together, 使用他们的 为双方的利益联合推进. 在他的实验室里，辛普森和同事们发现了一种绿藻 回应他的假设 它将.

“基本上，这可能会引发动物的起源，”他说.

天气有多冷??

然而, there is uncertainty about how cold it was 和 how much that cold varied during Snowball Earth. Current methods suggest that the average global temperature in this period was about 20 degrees C, 或华氏68度, 不会把地球变成滚雪球的水平. 这就是相信的用武之地.

相信, 地质科学副教授, 研究由碳酸钙制成的砂粒，称为鲕粒. 这些沙粒可以聚集物质，并在滚动时变得更大, 而不是任何其他类型的沙粒, 一般来说，它被传递得越多，就越小,”她说。.

相信’s idea was to explore whether the size of ooids could reveal things about the environments in which they formed. 液体受到两种过程的影响:物理和化学. 

Physically, the s和 grains are abraded as they roll around 和 collide with other grains. 这些摩擦和碰撞使颗粒收缩. 

从化学上讲，沙粒可以随着新矿物质的沉淀而生长. Originally, 相信 framed these reactions as reflecting the seawater in which they’re forming. “So, 例如, 如果它相对于这些碳酸钙矿物质更饱和, 然后矿物沉淀的速度更快, 这也许可以解释为什么你会得到更大的液体.”

But her calculations based on water viscosity didn’t suggest that ooids would grow as large as they did during Snowball Earth. 在世界各地的一些地方都发现了这一时期的巨型小行星. 特罗尔的研究重点是一种叫做钙石的碳酸钙, which forms only in very cold conditions 和 which was discovered in a Norwegian fjord. 

在这些稀有的, 喜冷的碳酸盐矿物可以长得比较大, 直径大于2毫米的. 相信 notes that ooids of this size 和 composition form only in certain temperatures; thus, the diameter of these ooids could be a proxy measurement of Earth’s temperature for the last 2.50亿年.

回答一个大问题

在世界银行的资助下.M. 凯克基金会, 相信, 辛普森和他的同事将从世界各地收集巨大的卵泡样本, measure them 和 analyze the samples to determine the nature of minerals they were originally composed of.

“那, 反过来, can tell us something about the chemistry 和 water temperature in which they formed,特罗尔说。, 注意到这些结果将与实际记录进行比较. 

The goal is to answer a big question: “Does the fossil record agree with the predictions we would make based on this theory from this new record of temperature?”

Undertaking such potentially ground-breaking research is both nerve-wracking 和 also quite exciting, 辛普森和特罗尔说. 

安妮·希恩, 地质科学系教授兼系主任, praised the scientists: “The project benefits not only from the talent 和 creativity of 相信 和 辛普森 but also from their willingness to step outside of their disciplines 和 take risks. This work exemplifies how cross-disciplinary collaboration can push the boundaries of Earth science 和 drive groundbreaking discoveries.”

南希·J. 史蒂文斯, 科罗拉多大学自然历史博物馆教授兼研究所所长, 观察到:“复杂多细胞生命的起源是一个令人兴奋的谜题, 和 它将 be remiss not to point out how 相信 和 辛普森 have selected a topic 和 这种方法反映了当代研究的现状. Organisms able to join forces to unlock new solutions can navigate challenging environments, 并最终发展壮大.” 

相信 和 辛普森’s work also has potential implications for the human quest to find life elsewhere in the universe, 以为说. 如果极端恶劣和寒冷的环境能刺激进化变化, “then that is a really different type of thing to look for in exoplanets (potentially life-sustaining planets in other solar systems), 或者想想(生命)何时何地存在.”

总部设在洛杉矶的W. M. 凯克基金会于1954年由已故的W. M. 凯克是苏必利尔石油公司的创始人. The Foundation’s grant making is focused primarily on pioneering efforts in the areas of medical research, 理工科和本科教育. The Foundation also maintains a Southern California Grant Program that provides support for the Los Angeles community, 特别强调儿童和青年. 欲了解更多信息，请博彩平台推荐 www.wmkeck.org.