Table 3 Major concepts relating to adaptive evolution by natural selection, summarizing both correct and intuitive (incorrect) interpretations (see also Fig. 2)

Existing variation among individuals

Common and important. A fundamental requirement for evolutionary change

Rare and/or unimportant. Deviation from “essence” or “type” of the species. Not important in evolutionary change

Origin of new traits

Arise in an undirected fashion by random mutation. Some detrimental, some neutral, some beneficial. Sorted according to effects on organismal reproduction after they arise

Arise in response to need. Always beneficial. Offspring may exhibit new beneficial traits even if the parents did not possess them. The types of new traits that occur are determined based on the environment

Inheritance

Traits are inherited from parents regardless of whether they are beneficial or detrimental. Physical changes in parents are not passed on. Heritable differences between parents and offspring are due to mutation and recombination

Only beneficial traits are passed on. Beneficial physical changes in parents are passed on to offspring. Heritable differences between parents and offspring are due to improvement in response to needs

Adaptation

Due to non-random differences in survival and reproduction among variable individuals over many generations. Individual organisms themselves do not change. The proportion of traits changes from one generation to the next as some traits are passed on at a higher rate than others

Due to response to need or an effort to change by individual organisms. Organisms change over their lifetimes to become better able to survive and pass these changes on to offspring. Any differences between parent and offspring will be in the direction of further improvement. The entire species transforms in response to need