In recent years a popular tactic among creationists has been to get "disclaimers" put in school science texts. Because creationist efforts to have creationism taught alongside evolution have failed, they want to use disclaimers to cast doubt on the truth of evolution by telling students something like "evolution is only a theory." In fact, the close similarity of all these disclaimers is a sign that they are part of an organized effort by Evolution Deniers to undermine science in schools.
The first attempt to insert a disclaimer into science textbooks across an entire state occurred in Washington in 1998:
This textbook discusses evolution, a controversial theory some scientists present as a scientific explanation for the origin of living things, such as plants, animals, and humans. No one was present when life first appeared on earth. Therefore, any statement about life's origins should be considered as theory, not fact.
The word "evolution" may refer to many types of change. Evolution describes changes that occur within a species. (White moths, for example, may "evolve" into gray moths.) This process is microevolution, which can be observed and described as fact. Evolution may also refer to the change of one living thing to another, such as reptiles into birds. This process, called macroevolution, has never been observed and should be considered a theory. Evolution also refers to the unproven belief that random, undirected forces produced a world of living things.
There are many unanswered questions about the origin of life which are not mentioned in your textbook, including: Why did the major groups of animals suddenly appear in the fossil record (known as the "Cambrian Explosion")? Why have no new major groups of living things appeared in the fossil record for a long time? Why do major groups of plants and animals have no transitional forms in the fossil record? How did you and all living things come to possess such a complete and complex set of "Instructions" for building a living body?
Study hard and keep an open mind. Someday, you may contribute to the theories of how living things appeared on earth.
Evolution Disclaimers Misrepresent Science
It is true that no one was around when life first appeared, but evolution is not about the origins of life, it is about how life developed. This "mistake" is made exclusively by creationists trying to confuse and mislead people about evolution — when you see this sort of claim, you can be sure a creationist agenda is behind it. The same is true about presenting evolution as a theory rather than as a fact — evolution is both, but only creationists misrepresent this to people.
It is not at all true that macroevolution (or speciation) has never been observed and is "only" a theory. Speciation has been observed in both the field and in the lab. Moreover, evolutionary biologists don't place a great deal of emphasis on the difference between microevolution and macroevolution because the line between the two a feature of our perception of the world — there is no logical or biological barrier between them.
It is true that there are debates among scientists about some conceptual issues regarding how evolution can and does proceed; none of these debates, however, occur over whether or not evolution actually occurs, contrary to what the disclaimer implies. This is a common creationist tactic of misrepresenting genuine scientific disagreement over details as a nonexistent disagreement over general principles.
Disclaimers are a Political Endorsement of Creationism
Little to none of the information contained in the disclaimers has any scientific basis. The disclaimers are not discussing or furthering science at all — if there were important scientific caveats about evolution which needed to be conveyed to students, they would be presented in the body of the text rather than on a sticker created by politicians.
Use of the disclaimer is a political rather than a scientific act, furthering political rather than scientific goals. The disclaimer is being used to communicate to students no less than five separate creationist myths, misunderstandings, and distortions about evolution. Creationists aren't able to get their message presented as part of the actual lesson plan, so they are using disclaimers to get around court rulings.
Disclaimers Implicitly Misrepresent Science
Much of what is in evolution disclaimers could be written about many other aspects of science as well. No one was around when the earth and solar system formed. There are scientific debates over the meaning of quantum theory. Everything in science is supposed to proceed by tentative theories rather than dogmatic pronouncements.
Why aren't there additional disclaimers for geology, physics, chemistry, and other aspects of science? Why not have a general disclaimer emphasizing that science is always tentative? The answer is obvious: this isn't about science or education; instead, it's about powerful religious lobbying to have one aspect of science education weakened in order to pave the way for their religious beliefs to be taught in its place.
One implicit message in the disclaimers is that there is something "different" about evolution which requires it to get a special treatment or caveats. The truth is exactly the opposite, which means that students are being taught something fundamentally false about what science is and how science operates.
Why Disclaimers Are Wrong
Disclaimers represent a political and religious interference with scientific education. The government has an interest in determining what students learn in public schools, but no government body has the authority to force schools to teach falsehoods as part of a political and religious agenda.
Science classes exist to teach students about science, not to indoctrinate them in a religious world view which they may not already share. If parents disagree with science, they can teach their perspective at home and in their church; they should not, however, expect science education to be distorted and undermined to accommodate their dogmas.