TOEFLスピーキング Task 3

Niche Construction refers to the process by which organisms actively modify their environment, thereby altering the selective pressures they and other species face. Unlike passive adaptation, niche construction involves organisms shaping their habitat in ways that influence their own evolution and that of their offspring. For example, beavers building dams create ponds that change water flow and vegetation, affecting not only their survival but also the availability of resources for other species. This concept highlights the active role of organisms in their own evolutionary trajectory.

Professor: Today we discussed niche construction, and I want to give you a clear example from a study on a type of marine snail. These snails live on rocky shores where the waves are strong. They have a behavior of burrowing into the soft mud beneath the rocks, creating small pits. These pits trap water and organic matter, forming a stable microhabitat. Over time, this changes the local environment by allowing algae and small invertebrates to thrive in areas that were otherwise bare. As a result, the snails themselves benefit because they have more food sources nearby. Interestingly, their offspring also survive better because the pits reduce wave impact and provide shelter. So, you see, the snails didn't just adapt to the rocky shore; they actively modified it to their advantage, demonstrating niche construction.