So we’ve been talking about how animals have developed different ways of surviving and one way is from having developed special physical characteristics that helped protect them from the dangers in their environment. These are known as protective adaptations and there are two different kinds. Some animals have defensive adaptations. That means they protect themselves by having body structures that make it hard for predators to get at them. And other animals have offensive adaptations, body structures that keep predators away. All right, let’s start with the turtle. It’s a good example of animal with defensive adaptation. Since you’ve probably all seen turtles, you already know that it has a hard shell that covers its back and vital organs. Its shell is a special physical characteristic and it’ so strong, it won’t break or split open, making it very hard for predator to get at it. The turtle also has a flexible neck, so it can pull its head down under its shell. Its legs can also fold up under the shell and provide more protection still. All right, but now, let’s talk about the porcupine. That’s an animal that protects itself with an offensive adaptation by threatening a predator with physical harm. Uhm…in case you haven’t seen a porcupine recently, just imagine an animal with a small body that is covered with thousands of long sharp needle-like quills. Those quills are its special physical characteristic. So whenever a predator gets too near, when it brushes against a porcupine, those sharp quills come loose and become embedded in the predator’s skin. So predators know enough to stay away because they see the porcupine’s threatening quills and they don’t want to risk being hurt by them.
Using points and examples from the lecture, explain two different protective adaptations.
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 risk being treated in this way again. Therefore, by giving out these two examples, the professor illustrates two different protective adaptations.
vt. 欣赏；感激；领会；鉴别 （appreciate的第三人称单数）
They don't have any confidence that houses will appreciate in value.(TPO49-20)