Day 54 Humans arrived in the Kaliko Islands about 7,000 years ago

Humans arrived in the Kaliko Islands about 7,000 years ago, and within 3,000 years most of the large mammal species that had lived in the forests of the Kaliko Islands had become extinct. Yet humans cannot have been a factor in the species' extinctions, because there is no evidence that the humans had any significant contact with the mammals. Further, archaeologists have discovered numerous sites where the bones of fish had been discarded, but they found no such areas containing the bones of large mammals, so the humans cannot have hunted the mammals. Therefore, some climate change or other environmental factor must have caused the species' extinctions.

Write a response in which you examine the stated and/or unstated assumptions of the argument. Be sure to explain how the argument depends on these assumptions and what the implications are for the argument if the assumptions prove unwarranted.

五问：

（1）“Humans arrived in the Kaliko Islands about 7,000 years ago, and within 3,000 years most of the large mammal species that had lived in the forests of the Kaliko Islands had become extinct”和“there is no evidence that the humans had any significant contact with the mammals. Further, archaeologists have discovered numerous sites where the bones of fish had been discarded, but they found no such areas containing the bones of large mammals”是事实，“Yet humans cannot have been a factor in the species' extinctions”是结论，值得反驳吗？

（2）没有证据证明人类与哺乳动物有接触，就意味着人类与哺乳动物一定没有接触吗？是否可能证据存在，只不过尚未被找到而已？或者时间久远，证据已经消失。

（3）是否可能存在这样的一种情况：人类与哺乳动物并没有过多的接触，但依旧造成了它们的灭绝？你能说一说这样的可能性吗？例如：人类破坏了食物链，人类活动造成环境污染，或者人类过度砍伐森林破坏了动物的栖息地等。

（4）没有发现被丢弃的哺乳动物骨骼，就意味着人类没有猎取这些哺乳动物吗？你能否说说，在什么情况下人类可能会猎取了哺乳动物却没有抛弃它们的骨骼？比如：大型哺乳动物的骨骼非常适合用来制造工具，因此没有被遗弃等。

（5）大型哺乳动物的灭绝不是由人类导致的，就一定是气候变化或者是环境因素造成的吗？是否有可能是该物种自身的原因造成的？比如：疾病或者其他天敌物种大量侵入等。