Explain what things might cause adaptation to occur?
Any stress can cause adaptation to begin. Stress would come from another system or organism or change from the same system. An example would be humans putting on clothes to protect their bodies as the weather changed either where they were at or because they were moving to another climate area.
Adaptation may occur in a species such as if there were a whole bunch of red moths who stood out in stark contrast to their backgrounds. All the moths of that species may be eaten except for a few who were not so brightly contrasted against the background. Those darker moths may give rise to offspring that are also dark or darker until a balance is reached in that moth species population.
Stresses can occur that are beneficial to one species and detrimental to another. In this cycle the benefitted species will thrive while the species experiencing detriment will not. Warmer weather in certain parts of Alaska would increase the mosquito population for a longer period of time. However, warmer weather would also allow permafrost to melt making it difficult for many more species who need the ground to stay firm by being frozen. Now the species needing firmer ground would probably adapt by moving north toward cooler weather with more solid ground. The mosquitos would adapt by populating warmer areas that previously were uninhabitable due to the temperatures needed for their lifecycle.
There can be subtle or catastrophic stresses that force all living things to adapt. In a system where there are no new stresses or changing stresses the system remains in balance. This is not likley to occur in nature as we know it for each species either relies on another or feeds on other species. Plus, the Earth is forever changing in subtle ways that can only be seen clearly from the perspective of geologic time.
