Genetic variation or Genetic drift
a cell adapts using natural celection in the long term
in the short term, look at this Wikipedia article.
https://en.wikipedia.org/wiki/Cellular_adaptation
About 23 percent of incoming solar energy is absorbed in the atmosphere by water vapor, dust, and ozone, and 48 percent passes through the atmosphere and is absorbed by the surface. Thus, about 71 percent of the total incoming solar energy is absorbed by the Earth system.
