Dr. PZ Myers has an op-ed article he wrote for the Minnesota Star-Tribune regarding the teaching of evolution and why science teachers don't include Intelligent Design. It is a beautifully written piece and well worth reading.
Intelligent Design (ID) has failed to meet even the minimal standards of evidence and scholarship we should expect of the science we teach our children. Teaching it steals time from more vital subjects in which our kids should be grounded.
Science is a conservative process. Most college-level introductory textbooks contain only material that has stood the test of time and has been confirmed independently. ID proponents have not only failed to provide any evidence for their thesis, they aren't even trying. There are no labs doing research on this subject; all the papers the Discovery Institute has tried to publish are exercises in spin, in which they try to distort biology researchers' work to fit their preconceptions. With no established body of results, no current work, and no promising prospects for future research, why should ID be supported? It's a dead end. It is absurd to propose that our kids learn about a subject that no legitimate scientists are pursuing and that has no utility.
With no track record to earn the respect of scientists and educators, ID is attempting to circumvent the accepted standards of testing and validation to sneak into our schoolrooms—it's cheating. It takes a great deal of hard work and persistence and time and evidence to establish a scientific idea, work that should not be shirked by taking the easy route and asking the government to legislate a concept into the schoolrooms. Yet this is exactly the strategy ID proponents are following: spreading propaganda to persuade school boards and state education departments to insert the ideological dogma of ID into classrooms, in the absence of support from scientists and informed science teachers.
Contrast ID with how legitimate scientific work gets into the curriculum. There is an active ferment of new ideas, new experiments, and new evidence constantly bubbling up in the scientific literature. Many controversies work themselves out in the pages of Nature or Science or other journals, and prompt hypothesis testing and the gathering of new evidence. If an idea is well-supported by the evidence, it gains wider currency within the scientific community, and eventually works its way into the science textbooks, which are usually written by people with a solid research background in their discipline. Biology books are written by biologists, not by the hodge-podge of lawyers, philosophers, theologians, rhetoricians, and rare scientists willing to abandon scientific principles found in the ID movement. Textbook content should accurately reflect the general opinion of the scientists who do real work in a field.
And what is the state of modern evolutionary biology? Thriving, growing, and more productive than ever. To name a few examples, in paleontology within the last year, we've had the amazing discoveries of Homo floresiensis, the Indonesian "hobbit", and remarkable finds from Dmanisi, Georgia. The human genome project, and genome projects analyzing other organisms, has been yielding research dividends as this wealth of data is analyzed from an evolutionary and comparative perspective. We are beginning to tease apart the genetic differences that make human brains different than those of chimpanzees. Molecular studies of protists are revealing the roots of multicellularity. We study oncogenes, genes that when damaged can cause cancers in humans, in nematode worms. Epidemiologists study looming disease threats, such as bird flu and the Marburg virus, using evolutionary principles.
My own discipline of developmental biology has been revolutionized in the last few decades as we've embraced evolution more fully than before; new papers in the rapidly growing field of evo-devo, or evolutionary developmental biology, pile up on my desk faster than I can read them. This is a genuinely exciting time to be studying biology, at a time when new syntheses of various disciplines with the ideas of evolutionary biology are fueling new innovations, new discoveries, and invigorating evolution yet further. When students ask me about the hot fields that promise great careers, I steer them towards evo-devo (and developmental biology in general, of course), bioinformatics, proteomics, and genomics, all fields in which knowledge of evolution is indispensable.
Note that I do not and cannot recommend anything to do with ID.
ID is a sterile philosophy whose proponents spend their time lobbying school boards, producing nothing new, and with no promise of new ideas for the future. Asking our schools to teach ID is like suggesting that they offer instruction in buggy whip manufacture—it's a futile exercise that is going to leave the students unprepared for both college and the real world. As a university instructor, I want my incoming students to be well versed in the fundamentals of biology, which includes evolution but not the empty pseudoscience of ID, so that we can move quickly to the real excitement of modern biology...which is almost entirely informed by the concepts of evolution.