The variation of organisms within a species increases the likelihood
that at least some members of the species will survive under changed environmental
conditions, and a great diversity of species increases the chance that
at least some living things will survive in the face of large changes in
the environment.
| NSES Content Standard C
Life Science: Biological evolution Grades 9-12, page 185 Species evolve over time. Evolution is the consequence of the interactions of (1) the potential for a species to increase its numbers, (2) the genetic variability of offspring due to mutation and recombination of genes, (3) a finite supply of the resources required for life, and (4) the ensuing selection by the environment of those offspring better able to survive and leave offspring. |