Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In fresh water, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between fresh water and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following?
A) evolution
B) trade-off
C) acclimatisation
D) adaptation

Question

Quizplus · Accepted Answer

The changes made in the cells of the gills during the lifetime of an individual salmon are an example of acclimatization, which refers to a reversible physiological adjustment to a changing environment. It is not an example of evolution, which involves genetic changes occurring over many generations. Trade-off implies a balance between two or more benefits and costs, which is not relevant in this context. While the changes in the salmon's gills can be considered an adaptation, this term usually refers to a genetic change that enhances an organism's survival and reproduction in a particular environment, rather than a physiological response to a changing environment.

Chum Salmon (Oncorhynchus Keta) Are Born in Freshwater Environments and Then