托福口语 Task 3

In biology, the term 'commensalism' describes a symbiotic relationship between two species in which one organism benefits while the other is neither helped nor harmed. This contrasts with mutualism, where both species gain advantages, and parasitism, where one species benefits at the expense of the other. Commensalism often involves a smaller organism using a larger host for transportation, shelter, or food, without affecting the host's survival or fitness. The concept highlights how ecological interactions can be one-sided yet neutral for the unaffected partner.

Professor: So, let me give you a classic example of commensalism. Think about the remora, also known as the suckerfish. Remoras have a specialized fin on top of their heads that acts like a suction cup. They attach themselves to larger marine animals, like sharks or sea turtles. When the shark feeds, it scraps food particles and leftovers that the remora then eats. So the remora gets a free meal and a safe ride. Now, does the shark get anything from this? Not really. Does the shark suffer? No. The shark doesn't lose energy, isn't slowed down significantly, and isn't harmed in any way. The remora just tags along. So here, the remora clearly benefits, while the shark is completely unaffected. That's commensalism in action.