The high temperatures in the desert environment can kill Beetles Large Beedles cannot burrow into the sand to escape the heat. Therefore, fewer of the large Beetles will survive.
The Beetles are affected by a deadly disease that spreads rapidly through the desert. Green beetles are susceptible but brown beetles are resistant
Did the desert environment CAUSE adaptive variations or did it SELECT adaptive variations?
I think it caused?
There are two things here: heat, and disease.
The heat could act to select smaller beetles, but we don't know anything about size of the green vs brown beetles.
The disease: Green beetles are susceptible, brown are not. So apparently, there are no adaptive variants being caused, but brown are being selected because of disease resistance. One hopes they have some mechanism to avoid heat.
To determine whether the desert environment caused or selected adaptive variations in beetles, we need to understand the difference between these two processes in the context of evolution.
1. Caused: If the desert environment caused adaptive variations in beetles, it means that the environmental conditions directly led to the emergence of these variations. In this case, the high temperatures in the desert would have directly caused the beetles to develop characteristics that make them better able to tolerate or survive in hot environments.
2. Selected: On the other hand, if the desert environment selected adaptive variations, it means that the variations already existed within the beetle population, and the environment played a role in determining which variations were more advantageous for survival. In this case, the high temperatures in the desert would not directly cause the beetles to develop new characteristics, but rather they would favor the survival and reproduction of beetles with pre-existing characteristics that provide better heat tolerance.
Taking this information into account, the resistance of brown beetles to the deadly disease in the desert suggests that this variation was already present in the beetle population before the disease spread rapidly. Furthermore, the inability of large beetles to burrow into the sand to escape the heat suggests that their survival is reduced in the high temperatures of the desert.
Therefore, in this scenario, it is correct to say that the desert environment selected for adaptive variations in the beetle population rather than causing them. The existing resistance of brown beetles and the decreased survival of large beetles likely existed prior to the beetles being exposed to the desert environment, and these characteristics were favored or selected for due to the specific conditions of the desert.