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) acclimatization
D) adaptation

Question

Quizplus · Accepted Answer

The changes made in the cells of the salmon's gills in response to moving between fresh water and salt water are an example of acclimatization, which is the ability of an individual organism to adjust to changes in its environment. This is not an example of evolution because it does not involve genetic changes that are passed on to offspring. It is also not a trade-off because there is no clear cost-benefit analysis involved. Adaptation is a broader term that can include both genetic changes and physiological acclimatization, but in this case, acclimatization is the more specific term that accurately describes the changes in the gill cells.

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