Q. Many creationists say that microevolution does occur, but macroevolution does not. Isn't microevolution just macroevolution taking place in very small increments?
A. From the perspective of an evolutionist who believes that evolution is responsible for all the diversity of life on earth, i.e. all organisms are descended from a common ancestral form, the process called macroevolution does consist of numerous little changes that could be described as microevolutionary steps. However, from the perspective of a creationist who does not believe that evolution is responsible for all the diversity of life on earth, i.e. all organisms are not descended from a common ancestral form, microevolution does not "add-up" to macroevolution over time.
From the creationist perspective, let's define these two types of "evolution."
Microevolution - variation within the Biblical kind.
Macroevolution - the changing of one Biblical kind into another kind.
The key to understanding the distinction between microevolution and macroevolution from the creationist perspective is the meaning of the term, kind, used in Genesis 1, and elsewhere in the Bible. In Genesis 1:11, 12, 21, 24, and 25 the Hebrew word, min, translated in English as kind, occurs 10 times. God states specifically that the organisms which He created were brought forth as kinds. About the plants God even states that they would bear "fruit with seed in them after their own kind." This is generally understood to mean that the plants, and all the creatures for that matter, were created by God to only reproduce their own kind, thus, one kind would not give rise to another kind. But just what is one of these Biblical kinds? The scientific term, species, was often considered to be synonymous to the Biblical kind, however, it is important to recognize that our fairly recent invention of the term, species, does not necessarily have any relationship to that ancient Hebrew word, min. Moses, in fact, knew nothing of our current taxonomical classification system of phylum, class, order, family, genus and species. Thus, although scientists have made a strong case for the phenomena of microevolution, i.e. what we identify as one species changing into what we now identify as a different species, it does not then follow that these are examples of the Biblical kinds changing into different kinds.
An example of variation within the Biblical kind might be that a portion of the numerous varieties of hawks which exist today have developed from an original "hawk kind." Note what Deuteronomy 14:12, 15 says, "But these are the ones which you shall not eat: the eagle and the vulture, . . . and the hawk in their kinds." A Field Guide To The Birds, East Of The Rockies by Roger Tory Peterson lists only the species of hawk found in North America East of the Rocky Mountains, and just under the category (genus) called Buteo there are 9 different species listed. Many of these species are barely distinguishable except to an experienced bird watcher. An example of macroevolution would be archaeopteryx, an extinct bird known only from fossils, evolving into different kinds of birds like eagles, vultures and hawks.
Could microevolution occur within a kind? I certainly think so. It is, in fact, essential that organisms adapt over the generations to their changing environments; otherwise, all life would be threatened with extinction. But the adaptations of various kinds (species, as scientists would identify them) occur as a result of the variable genetic expression made possible by the vast amount of genetic information already present within a population of any given kind. However, each kind received the totality of its genetic information at Creation, and the expression of any characteristics related to that kind is limited to the genetic information with which it began. Evolution insists that new information can be added to a species' genome (the total amount of an organism's genetic information), arising by chance, through random mutations, and producing new characteristics in certain individuals of a population. Then, as a result of these new characteristics, those individuals have higher survival statistics and the characteristics become part of the overall population over time.
What should be noted is that there has never been any observation made of new genetic information being produced by random mutation, resulting in some new characteristic in an organism. The only observations ever made are that mutations result in the loss of genetic information. Sometimes the loss of information is beneficial to the organism in a particular environmental situation, but the benefits are never a result of new genetic information.
So, the crucial difference in the meaning of the term microevolution as used by an evolutionist in contrast to a creationist is that an evolutionist thinks microevolution requires the addition of new genetic information to a species' genome, but a creationist thinks microevolution requires the expression of genetic information already present. Obviously, it is the term, evolution, common to both microevolution and macroevolution, that tends to cloud the difference in the meaning of microevolution as used by evolutionists and creationists. Perhaps, the easiest way to clarify this confusion is to have creationists surrender the use of the term microevolution, and just use the more descriptive phrase, "variation within the kind," to describe this phenomena. I'm willing, and from now on, I'll do my best to be consistent, and leave the term, microevolution, to the evolutionists.