Testing the Role of Predation in Morphological Evolution of Marine Prey

捕食是一种生物为了食物而杀死另一种生物的行为，被认为对物种的进化和多样性（数量）有很大的影响。我们目前正在经历生物多样性危机（每天有70个物种灭绝），因此了解影响多样性和进化的因素至关重要。有一种“升级”假说，认为大多数动物进化的主要原因是为了更好地保护自己免受捕食者的侵害。化石记录提供了一个长期的天然实验室来检验这些假设。然而，由于不可能直接观察过去，因此很难估计捕食。因此，我们需要一种在没有直接观测的情况下估计捕食的方法。一种解决办法是利用捕食的痕迹，例如海洋无脊椎动物猎物外壳上的疤痕，来估计捕食的频率。例如，螃蟹经常用它们强有力的爪子打碎贝壳来吃蛤蜊。如果攻击失败，蛤蚌就会重新长出它的壳，现在壳上有一个修复的疤痕;我们可以在化石上看到这样的疤痕。

Predation, the act of an organism killing another for food, is believed to influence the evolution and diversity (the number) of species greatly. We currently are experiencing a biodiversity crisis (70 species go extinct per day) so understanding the factors that influence diversity and evolution is vital. There is a hypothesis of “escalation”, which suggests that the main reason why most animals evolve is to defend themselves better from their predators. The fossil record provides a long-term natural laboratory to examine such hypotheses. However, predation is hard to estimate because direct observations of the past are impossible. Thus, we need a means of estimating predation without direct observations. One solution is to use traces of predation, such as scars on the shells of marine invertebrate prey, to estimate the frequency of predation. For example, crabs regularly feed on clams by using their powerful claws to fracture the shell. If the attack fails, then the clam regrows its shell, which now has a repair scar; we can see such scars on fossils.