By David MacMillan.
3. You don’t evolve, your species does.
Creationists often conceptualize evolution as something which is purely vertical: successive changes from parent to child to grandchild to great-grandchild accumulating over time. They can hardly be faulted for this misconception, because this view seems to be shared by the general public and even reinforced by the sometimes-imprecise explanations and depictions of evolution by museums and science educators.
Evolutionary adaptation, however, does not happen in a straight line from parent to child. Rather, adaptation takes place throughout a population as different genetic sequences spread outward from parents to all their offspring and are recombined and reshuffled in many different individuals each successive generation. Evolution is wibbly-wobbly, timey-wimey stuff. It is the combination of changing genetic material across an entire population that makes major evolutionary adaptation possible; without this constant mixing and recombination from the entire population, evolution would grind almost to a halt. Evolution is a phenomenon that functions not at the level of the individual, nor at the level of individual lineages, but across the entire population within the species (Figure 1).
Figure 1. This hypothetical example depicts evolutionary change as an emergent property of the entire population. Both the “ABC” combinations (in shades of blue) and the “XYZ” combinations (in shades of red) offer a survival advantage and are passed on, while combinations of the two (shown in shades of purple) are detrimental and are removed from the population. No specific mutation order is required; as long as the selection pressure remains steady, the mutations accumulate together (essentially “finding” each other) and two separate genotypes emerge.