TOEFLスピーキング Task 3

In biology, the term 'behavioral adaptation' refers to an action an organism takes to survive in its environment. Unlike physical traits, behavioral adaptations are learned or instinctive responses that help an animal find food, avoid predators, or reproduce successfully. These behaviors often develop over generations through natural selection, as individuals with beneficial behaviors are more likely to survive and pass on their genes. Understanding behavioral adaptations helps scientists predict how species may respond to environmental changes.

Professor: Let’s look at a classic example—the three-spined stickleback fish. In some lakes, this fish faces a predator called the pike. When a pike attacks, the stickleback’s instinct is to dart away quickly. But in lakes without pike, sticklebacks don’t show this strong escape response. Why? Because in those safe lakes, the energy spent on constant darting would be wasted. So, over many generations, the fish in pike-free lakes evolved a calmer, less reactive behavior. In contrast, sticklebacks in pike lakes developed a faster, more intense escape response. This difference isn’t physical—it’s a learned, inherited behavior that improves survival in each specific habitat. So, the stickleback’s escape response is a perfect example of a behavioral adaptation.