سوالات گفتاری ۴

TPO 62- Speaking Question 4

Listen to part of a talk in a biology class.

Professor: Okay. So on the topic of animal survival strategies, one type of strategies that’s fascinated people for centuries is protective resemblance. That’s when animals resemble their environments in some way or another by taking on the color or shape or both, of the physical objects that are behind or beneath them.

Today we’ll talk about two kinds. Which kind of protective resemblance an animal has, well, it depends on whether the animal moves through different environments in the course of its life or whether its environment is more or less permanent.

For example, animals like the horned frog. Well, they’ve got the permanent kind of protective resemblance, which is fine, because well, during the course of their lives, they don’t visit other places. So the horned frog is brown, just like the dead leaves on the forest floor where it lives. And it’s got brown lines running down its body, just like the veins of the leaves. The color and shape of its protective resemblance is fixed, like its environment. So when the horned frog is on the forest floor, it’s almost impossible for predators to see it.

Now other animals like the Anole lizard display a different sort of protective resemblance. They actually change color, which is important for them because they travel through different environments as they live and grow. So the protective resemblance they exhibit is adaptive, depending on the environment they are in. The Anole lizard has special moving pigments in its cells, which change to match the color of whatever environment it’s currently occupying. If the Anole lizard is walking among the dead leaves of the forest floor, it’ll turn the same brown color as the leaves. But if the Anole lizard runs into some green shrubs, well, it’ll turn green.