Evidence for Evolution
There's plenty of evidence to show that life changes over time. We can see this over long time periods by examining the fossil record and we even see it over shorter time periods with less dramatic changes amongst current species. The reason we don't see dramatic change directly is that the process is quite slow and fossils are the only way we have to "look back in time" far enough.
Its hard to deny that life changes, but many people attempting to refute evolution will say something like "yes life changes, but not significantly, you can't make new species that way." Again, this is a failure to extrapolate to the enormous time periods involved. Anyone who denies life has been on Earth for billions of years is ignoring the undeniable evidence we now have (this is covered in other parts of my Web site).
Some supporters of Creationism point to the debates going on amongst scientists who study evolution as evidence the theory is "in crisis" or "found to be untenable". This simply isn't a fair conclusion to form, and many Creationists know it. The big surprise with evolution is that it seems to have happened it short bursts of change with long periods of stability in between. Originally, it was assumed, that the change would be continuous and gradual. Debating the details does not make the theory untrue. Evolution did happen, its just a matter of how quickly and at what times. There's no doubt that most change occurs during mass extinctions where natural disasters: climate change, volcanism, meteor impacts, cause many species to become extinct. Maybe it shouldn't really be a surprise that evolution occurs mostly during these periods.
The Bible implies that all living things were created in their current form. Also, there is no time in the Bible for evolution to occur. Have a look at my religious stories page to see why the Biblical stories can't be true.
So there are two theories: one where all living things were created in their current form, they don't change, the different types of living things were created quite close together, and this all happened recently (thousands, not billions of years ago), and another where living things constantly change but very slowly (over billions of years).
Only one of these theories is supported by the scientific evidence we have. The fossil record, the study of different species' genetics, and observations of present day species all confirm the evolutionary model is correct. Note that evolution doesn't mean there is no God, it just means the most simple, consistent explanation of what we see today is through evolution and that the Bible is definitely wrong, which means all Christian beliefs are questionable.
The following is a partial list of the evidence which supports evolution. I have kept the explanations short, but there is plenty of detail on the Internet as well as in any biology text book.
Vestigial structures are anatomical or molecular structures which no longer perform the original function. Note that they don't have to be useless to be vestigial. For example an ostrich wing is vestigial because it is a complex structure used for flight in other birds which is used simply for balance and display. Only evolution can provide a reasonable explanation for this. Its not impossible that God would have used a complex structure for a simple function, but it makes a lot less sense.
Links between different types of animals have been difficult to find but many Creationists deny their existence completely. They are wrong. The links have been found. A famous one is Archaeopteryx - the link between dinosaurs and birds. This is such a good example that Creationists have had to resort to calling it a fraud. Its not. The reasons they call it a fraud are all incorrect, there are multiple examples, all with well-defined feather structures in an arrangement that couldn't be faked.
Attempts at Discrediting Evolution
Creationists, and other groups who attempt to discredit evolution, use a number of techniques in advancing their arguments. Some have little, if any, merit while others do have some veracity and are worth considering. I encourage you to totally ignore any argument which relies on emotive statements. Common emotional statements often say something like "humans evolved from monkeys". There's two problems here: one is, its a simplified emotional argument trying to make the scientific community look foolish. The other is; that's not what evolutionists say anyway, the fact is humans and apes (not monkeys) evolved from a common ancestor so statements about "monkey's uncles" etc should be immediately discarded.
Another common trick is to quote scientists who are debating the details of the theory and try to make it look like they are rejecting the theory itself. The old trick of partial quotes, outdated quotes, and quotes from non-specialists are often used. They often reference these quotes (to make their work look more official and scientific) so you should look for the source to see what the person was really saying.
Attempts at Discrediting Evolution: Transitional Forms
One of the common points people mention when trying to discredit evolution is the lack of transitional forms in the fossil record. It is true that there are many missing transitional fossils or "missing links" but this isn't surprising because only a small part of one percent of animals ever become fossilised. In some ways it is surprising that so many transitional forms do exist. Its not necessary to discover every transitional fossil to show that species change, there is enough evidence to clearly show species changing form for certain types of animals (and plants). I've got some examples of transitional forms here.
Attempts at Discrediting Evolution: Human Fossils
Some creationists claim human evolution is based on a few fragments of fossils, but there are thousands of hominid fossils now. Lubenow (1992) found that there were fossils from almost 4,000 hominid individuals catalogued by 1976. Later research (Handprint 1999) found there were fossils of about 150 Homo erectus individuals, 90 Australopithecus robustus, 150 Australopithecus afarensis, 500 Neanderthals, and more. Is that not a reasonable number?
Attempts at Discrediting Evolution: Thermodynamics
Many people misunderstand the relevance of thermodynamics in relation to evolution. They say that "order" doesn't increase spontaneously, so complex life couldn't arise without outside help.
The second law of thermodynamics says, that no process can exist where the sole result is the transfer of energy from a cooler to a hotter body, which is often stated as "the entropy of a closed system cannot decrease." Entropy is an indication of unusable energy and often equates to intuitive notions of disorder or randomness. Creationists interpret this as meaning that things invariably progress from order to disorder. But this only applies to closed systems. Any system which receives energy from outside (eg Earth from the Sun) can decrease entropy.
Attempts at Discrediting Evolution: Mutations
Another common misunderstanding creationists have relates to mutations. They say mutations are never favourable. Another error is saying mutation can't result in new "information" appearing. Both of these ideas are wrong.
A good example of favourable mutation are bacteria that "eat" nylon. More accurately, they eat short molecules found in the waste waters of plants that produce nylon. Since the chemical bonds involved aren't found in natural products, the enzymes must have arisen since the time nylon was invented, in the 1940s. It would appear this happened by new mutations in that time period.
These enzymes which break down the nylon oligomers appear to have arisen by frameshift mutation from some other gene which codes for a functionally unrelated enzyme. This adaptation has been experimentally duplicated. In the experiments, non-nylon-metabolizing strains of Pseudomonas were grown in media with nylon oligomers available as the primary food source. Within a relatively small number of generations, they developed these enzyme activities. This is an example of a favourable mutation observed in the lab as well as in nature.
New information forming is actually common, through gene duplication. All intermediate stages can be found in nature, from a single gene with alternate alleles to nearly identical duplicated genes with slightly different functional alleles to gene families of evolutionarily related genes with different functionalities.
Comment by Anonymous on 2007-03-26 at 21:15:15: I think evolution is basically a sound theory also, but it is incomplete in its current form. Science has made inroads, but science is not complete - almost by definition. Incidentally, have you watched the 'Does God Exist' series by John Clayton? This is an example of a learned Christian and amateur geologist who does believe in evolution . Its rather a good series with much science and geological evidence and arguments and plenty of engaging and entertaining discussion. link.
Comment by OJB on 2007-03-26 at 22:17:42: In what way do you think evolution is incomplete? I think you're right, that science is usually incomplete. No matter how much information we discover, there always seems to be more subtlety and complexity we still need to examine. I haven't watched the TV series you mention and I don't think I could justify a 4G download. Looking through the table of contents though makes it look fairly routine: irreducible complexity & the anthropic principle, the cause of the cosmos, etc.
Comment by Anonymous on 2007-06-25 at 08:10:09: Most biology books are not correct. A lot of them are not updated and a lot of the experiments that went on years ago, scientists already know they are wrong. Science is starting to prove evolution wrong as it advances. I believe you are stuck in the earlier days before new technologies were created.
Comment by OJB on 2007-06-25 at 18:54:35: Most biology books are not correct. Really? I can't find any major errors in the ones I've looked at. There are a few minor details which have been modified but the basic ideas are as sound as ever. If you have some good examples I'd love to hear them. Science is proving evolution wrong? Well its strange that about 99% of biologists (who are scientists who specialise in biology and evolution) think its not only the best theory, but the only theory we have. Got any stats to prove that science is proving evolution wrong? No, I didn't think so. I'm afraid you're talking total nonsense.
Comment by Anonymous on 2007-06-26 at 07:58:46: Have you ever heard of the huge scientist, Lee Strobel?
Comment by OJB on 2007-06-26 at 18:02:39: I've heard of Lee Strobel, but he's not a scientist - he's a Christian writer. What's your point?