The creation/evolution debate is considerably hampered by the different meanings attached to the word 'evolution'. In general, the creationist defines it in same way that Darwin did in the title of his famous book: all living things descended from a common ancestor. In other words he claimed the first living cell emerged in some primordial soup and gradually developed into all the life forms we can now see around us.
While the evolutionist would agree with that definition, he may also use it to describe the kind of changes that can be observed due to natural selection and mutation, but alone could never produce a new kind of life-form. Creationist and evolutionist alike accept that these kind of changes take place, which can sometime result in such genetic ‘drift’ that creatures previously able to breed together are now unable to do so. When this has taken place it is considered that they have become a different species. The evolutionist would take this as solid evidence that evolution of species is indeed fact, and given enough time can continue to produce enough difference to achieve what Darwin claimed.
It is certainly the case that if one takes this kind of change to be evolution, then evolution has been observed. Furthermore, if the definition of the word 'species' is creatures unable to breed together, then evolution of species has been observed. Is this enough, though?
In order to distinguish between different types of life forms, the system of biological classification has been developed. In this classification, several levels have been identified, with the tiny kind of differences just mentioned at the bottom, and huge differences of body type at the top. So we have: Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.
In the excellent book Explore Evolution,* explanations of these categories are given, with the bumble bee and polar bear as examples. So the bumble bee falls into the classification of Eukarya, Animalia, Arthropoda, Insecta, Hymenoptera, Apidae, Bombus and terricola; while the polar bear is Eukarya, Animalia, Chordata, Mammalia, Carnivora, Ursidae, Ursus and maritimus.
* This book gives a very balanced representation of the opposing views of the evolutionist and creationist. My one criticism is that because there is no mention of the young-Earth viewpoint, the alternative understanding of geological time and formations and the reason for fossils is completely ignored. Therefore the creationist case is incomplete.
While the above categories may be of great help to those working in the field, the Bible gives a much simpler definition. It says God created everything after its own kind. So for example, we can have a dog kind and a cat kind. Thus, while through natural selection we can find in the dog kind coyotes, wolves, hyenas, etc., and through artificial selection with careful breeding we can have literally hundreds of breeds of dog, the dog kind can never change into a cat kind. This is precisely what we see when we observe all the living things around us.
So to give some kind of definition, we could say that a single kind is every species, past, present and future, that can trace its ancestry back to the same breeding pair God created during the creation week. He only created one man and one woman, but we are not told if He created only one male and female of all the other living species or more than one. If it was more than one, then we are referring to all those capable of interbreeding at the time they were created.
The creationist case is that while minor differences may occur at the species level, the amount of change required to produce difference at the higher levels is such that it could never happen. For example, one could play a variety of different games with a pack of cards by varying the number in the hand and the use to which they are put (different Species), but they could never be used to play chess (different Domain or Kingdom perhaps).
The diagrams below will hopefully demonstrate this. The evolutionist believes as a result of a net increase in specified complexity, there has been an ever-increasing variety of life forms arising from a single ancestor, rather like the branches of a tree (lower diagram). The creationist believes God created all the different kinds of living thing, which since have increased in variety via natural selection like the roots of a forest of trees (upper diagram); but none developed into different kinds because cat kinds can turn into lions and tigers, but can never become dogs or monkeys. All the change we can see is the result of the shuffling or loss of pre-existing DNA information, and never the result of new information coding for faculties not previously seen in a species.
So the phrase, ‘evolution of species’ can have two different meanings. Darwin’s use of the phrase was in the sense of all species evolving from a common ancestor. On the other hand, the creationist would claim that the only kind of ‘evolution of species’, both possible and observed, is limited to comparatively minor change within the ‘kinds’ that God created: there is no example anywhere in the world, fossilised or living, of any type of change that can be seen to be changing one kind of life form into another.
Evolutionists argue that mutations are sometimes beneficial, and a succession of such mutations will produce new kinds of living things. Indeed, this is how every living thing evolved from the first living cell.
A mutation that produces a beneficial change is not the same as microbe-to-man evolution. In order for that to occur new information has to appear in the DNA to code for new features not previously seen in the species, and there are no examples of this in existence. However, mutation that damages DNA information, which is therefore the opposite of evolution, can sometimes be beneficial. Fish living in total darkness in waters inside a cave would benefit from losing their eyes, as eyes are no help where there is no light; but their eyes can be damaged by swimming into things, which could then lead to disease and death. Winged insects on an island could lose their wings through mutation and in a strong wind survive where their winged counterparts were blown out to sea and drowned. In the case of Lenski’s experiment, E. coli benefitted by saving energy through losing some abilities that were previously there. See toward the end of the introduction to my comments on Richard Dawkins’ book for more details on this.
Mutation may sometimes be beneficial, but it is never a step toward a different form of life because it is always damage to existing DNA coding.