After reading some of the "Celebrate Darwin's Birthday" thread, it became apparent that there are some fundamental misunderstandings among the members here concerning evolutionary theory. This is an attempt to address a few and hopefully provide some understanding. 1. Common Ancestry This is often misunderstood as "we came from monkeys" or "we came from apes". First, Evolution broadly states that all life descended from a single organism. Strictly speaking, Evolution is not concerned with the origin of the first organism since it's focus is on how organisms change over time. Specifically, the "why are monkeys still around" comment is common and demonstrates a lack of knowledge about Evolution. What science states is that humans and other primates descended from a common ancestor (although it was an ape-like ancestor) that no longer exists on earth. This ancestor had offspring that over many generations separated into multiple groups. Each of those groups followed a different evolutionary pathway due to different selection pressures and mutations, changing over the course of millions of years. Some became extinct. Some eventually became chimpanzees. Some became gorillas. One group became homo-sapiens. This idea has been confirmed with beyond any reasonable doubt by genetic studies and DNA comparison. Techniques like identification of genetic markers and comparison of specific traces of genetic "events" (like retroviral dna insertion) confirm not only common descent but can give a general picture of how far removed our kinship is with various other species and in almost every case, it matches what would be predicted intuitively. I.E. we are more closely related to primates than dogs. We are more closely related to other mammals than reptiles. Etc... To deny the genetic science that confirms this idea is to suggest that the methodology or interpretation is flawed or incorrect. These are the same techniques used to convict or exonerate criminals using dna and the same techniques used in paternity testing. If the methodology is wrong, and indeed our entire understanding of dna would have to be wrong, then we should see those who deny common ancestry protesting the use of dna evidence in trials and paternity cases with at least as much zeal as protesting the teaching of evolution. Any conviction or exoneration based on dna evidence would have to be invalid. 2. You don't see x giving birth to a y. Evolution involves the accumulation of very small changes over vast periods of time. A good analogy is language. Think of how English has changed. It certainly reads differently today than it did when the Declaration of Independence was written. Go a bit further back in time and read some Shakespeare and some people begin to start feeling less comfortable understanding it. Now go read some original Chaucer. It can be understood but looks very strange and passages may be unintelligible. Now go all the way back to Beowulf in its original Anglo-Saxon. It cannot be read and understood without special training. One must learn a completely different language. All the way from the Anglo-Saxons to this post I am typing, there was no point that children could not understand the language their parents were speaking or vice-versa. There was no conscious intent to change the language or any clear lines of division between old English and middle English. It was just small changes in words and meanings with each generation that have accumulated over time to the point where we today speak a different language than "English" speakers during the time of Beowulf's composition. The same goes for speciation. 3. Evolution is just a theory. A theory in science refers to scope not validity. Any idea that has broad explanatory power for natural phenomena is a theory. It's a broad unifying prinicple. Like the theory of Gravity. There are lots of details that continue to be explored and there are still mysteries about gravity. Indeed, one of Einstein's claims to fame is that he in some ways showed the flaws in Newton's ideas about gravity. But the basic theory that objects with mass attract one another is still sound. It is a broad explanation, the details of which can be disputed. The germ theory of disease is another example. What germs and how they cause disease may not be known in every case. Yet, the broad idea that micro-organisms can cause disease in larger organisms is still sound and is a good explanatory basis. The theory of evolution is a broad explanation. In its most basic form it simply states that inheritance and accumulation of small changes due to mutation over large amounts of time leads to diversification of organisms. Natural selection influences changes by exerting pressures for survival and reproduction. Modern evolutionary theory also incorporates neutral changes such as genetic drift. Modern biologist are as confident in Evolutionary Theory as physicists are in Atomic Theory. In many ways biology today depends on evolutionary theory as much or more than physics depends on atomic theory. And while not every detail or question within the broad theory of evolution has not been analyzed or answered, it is no different than quantum theory or atomic theory which still have their mysteries as well.