Because of how widespread creationist misrepresentations of science and evolution are, the general public is unfamiliar with the fact that microevolution produces macroevolution. This is why authors of popular books on evolution need to explain in detail how and why this occurs. Despite being books aimed for a more general audience, the explanations of how microevolution leads to macroevolution are much the same as those found in biology texts aimed at students and specialized scientific reference books.
One of the most important points made by scientists involved in the modern version of Darwinism, Neo-Darwinism, was that Darwin's main contention in The Origin of Species was correct. Studying variation on an easily observed level was the key to understanding evolution. What Darwin called ''Variation under Domestication'' and ''Variation under Nature'' was like observing microevolution. As Darwin rightly asserted, the continuing accumulation of microevolution led to something much larger — transmutation or macroevolution. ...
Macroevolution. A major development in evolution, usually one species changing into another species. Macroevolution is synonymous with transmutation, the term familiar to Darwin. Generally, macroevolution is the process being referred to in discussions about evolution. The evolution of an organism from a common ancestor is macroevolution.
Microevolution. Changes or mutations in a species that do not result in transmutation. These changes can occur in a short period of time. The result of these changes or adaptations may be the formation of a new variety of the species. (Bacteria that become resistant to drugs have undergone microevolution.) Some creationists and proponents of Intelligent Design accept that microevolution occurs without conceding that macroevolution occurs.Charles Darwin and The Origin of Species Keith A. Francis
Microevolution refers to the results of the evolutionary process over short time scales and small changes. An example is a bacterium in a laboratory beaker experiencing a mutation that creates a gene that confers higher growth and division rates relative to the other bacteria and beaker. Microevolution, because it happens on a time scale that we're able to observe, tends to be a bit easier for us to wrap our brains around than macroevolution.
Macroevolution refers to the results of the evolutionary process typically among species (or above the species level; see Chapter 11) over long periods. Nothing is different about the process; nothing special is happening. Macroevolution simply refers to the larger changes researchers can observe when evolution has been going on for a longer time and involves processes such as extinction, which may have little to do with microevolution. Speciation, the process whereby one species gives rise to two, is an example of macroevolution. ...
Other than the time frame, no difference exists between micro- and macroevolution. The process isn't any different from what scientists can observe in a test tube in the laboratory (an example of microevolution); there's just been a lot more of it.Evolution For Dummies, Greg Krukonis, PhD & Tracy Barr [emphasis added]
Changes in allele frequencies in a population over time are referred to as microevolution, which can occur quickly and is directly observable. On a grander scale, macroevolution is long-term change, characterized by speciation that mostly occurs over deep, or geologic, time. Accumulated microevolutionary change results in macroevolutionary change. Microevolution and macroevolution lie on a continuum of change from small- to large-scale, both resulting from the same genetic mechanisms and the same four forces: mutation, gene flow, genetic drift, and selection.Human Origins 101, Holly M. Dunsworth [emphasis added]
I think that Dunsworth's explanation is noteworthy because she doesn't just point out that microevolution produces macroevolution, but also that the basic mechanisms are the same: "mutation, gene flow, genetic drift, and selection." This is critical because the creationist misrepresentations all center around the idea that microevolution and macroevolution are driven by fundamentally different forces. This is the only way they are able to admit that microevolution occurs while denying that macroevolution occurs. If they admitted that the forces behind both were the same, they wouldn't be able to maintain this illusion for themselves.
