Genetic drift happens when
well-adapted organisms survive and reproduce more often than poorly-adapted
organisms. <span>The statement that best sums up evolution is the
change in a population through genetic variation over time. Natural selection
may be through (1) differential
reproduction, that is, not all organisms are able to reproduce to their fullest
capacity because nature cannot simply sustain it and (2) acquire genes, that is
heredity.</span>
An individual skin cell develops differently from a muscle cell because the cells express different genes.
All the given cells present in the body, be it skin or muscle cells have the same DNA and the same set of genes. However, these cells are able to develop differently from each other due to the differential expression of their genes.
Differential expression of genes means that the different cells which perform different function although have the same set of genes, express different genes at different times and thus, look and function differently.
Skin and muscles cells also express a different set of genes and thus they develop differently from each other.