In the lecture, the professor talks about two different protective adaptations. There are two key points. The first key point is a defensive adaptation. Take turtle for example. A turtle has a hard shell covering its back and vital organs. And if it feels threatened, a turtle could fold its neck and legs into its hard shell so that they are all protected from its predators. The second key point is an offensive adaptation. For instance, a porcupine has lots of sharp needle-like quills which could scare its enemies to step back because they see how other predators are hurt by porcupines’ threatening quills and they don’t want to risking being treating in this way again. Therefore, by giving out these two examples, the professor illustrates two different protective adaptations.