An animal that can remember the significance of that large, nasty-looking thing with the big teeth and sharp claws will survive longer and produce more offspring.

　　译文：一种动物只有记住了长相丑恶(具有巨大牙齿和锋利爪子)且身体庞大的重要性，才能生存长久并繁殖更多的后代。

　　句型分析：本句是复合句，句子的主干为An animal will survive longer and produce more offspring。

　　定语从句：主语animal后接关系代词that引导的定语从句，关系代词代替animal在从句中作主语。在从句里，谓语动词 remember的宾语是the significance，它的后置定语为that large, nasty-looking thing with the big teeth and sharp claws;介词短语with the big teeth and sharp claws补充说明thing的特点。