Just had to comment on some comments that somone made earlier, (I believe it was FL2, but apologize if it was not) which betrayed a gross misunderstanding of the theory of natural selection when they claimed that it was in some sense a sentient force directing the process of evolution. This could not be further from the truth. Natural selection simply means that some members of a population will have heritable traits that allow them to survive or reproduce more efficiently in their environment than other members, and that, because they survive and reproduce well, those traits will be passed on. There is nothing purposeful, or directed about it, and nothing that implies progress. This is mainly due to the all important phrase, "relative to environment" that so many forget.
Let's play pretend for a minute. Lets pretend that intelligence is linked to a single gene, which in one allele (let's call it B) form codes for a protein that say, catalyzes the formation of synapses in the brain. Now pretend that the other allele (let's call it b) form codes for an altered form of the protein, which is incapable of assisting synapse construction. Now pretend that intelligence is directly related to the number of synapses in the brain, and we can now say that BB or Bb individuals will be more intelligent than bb indiviudals. Now lets say tommorow the sun begins giving off some bizarre form of radiation that gives everyone brain tumors. EXCEPT, that the malformed and up to now useless version of the synapse-forming protein happens to absorb, clean, up, or otherwise blcok this radiation. All of a sudden, it is adaptive to be stupid. In such a case the human species would evolve (and quite rapidly I might add) to be stupider than it was before, because only those people with the stupid gene will survive. This is still evolution by natural selection, even though it runs counter the what we would consider evolutionary "progress". Now obviously, this example is grossly oversimplified, and exaggerated, but it serves to illustrate that the key thing to remember about adaptivity is that it is relative to environment. A trait that is adaptive to a population in one environment, might be catastrophic in another.
Forget this simple fact, and you run the risk of falling into the trap of staight-line progress evolution like those bizarrely innacurate pictures of the amoeba turning into a fish crawling out of the water and turning into several creatures before arriving at "almighty man". That type of thinking (even by people who subscirbe to the theory, but don't properly understand it) is what gives people the idea that natural selection is some sort of sentient force directing towards a given goal. Also bear in mind that in some senses, you could argue that bacteria are more evolved than us, not less, when you consider that the number of generations in the 5-8 million years since our split with our's and the chimp's common ancestor, would take a population of bacteria a mere 25 years. Are they as "advanced" in terms of complexity? Of course not. But are they adaptive to the point where they can thrive in environments that humans with all their technology couldn't dream of surviving? Absolutely.
Sorry for the super long post, and for drifting around only semi-coherently with my thoughts.
... even carbon dating!
