Humanity is continuing to evolve - fact. The reason that so many have problems with this idea is that they have a misunderstanding of what evolution is and the evolutionary process.
What evolution is: A process by which a species of organism experiences genetic 'drift' (changes in the genetic code or in which parts of the code are active) that eventually results in enough drift that members of the subset have become a different species. The ONLY requirement evolution has is: Can the organism viably reproduce before it dies? If it can, congratulations! You survive. If not, thank you for playing - sorry, there is no consolation prize. Many, many creatures/species are NOT particularly well suited for life - but since they can (so far) pass this one requirement, they continue to exist. Rabbits are a good example - most are not very fast and very few are even remotely intelligent. They are prone to diseases that they die from (unlike say, rats, which just carry said diseases to pass along). They are tasty to most predators and have literally NO way to defend themselves short of 'I can run a bit faster than the other rabbit I am standing beside'. Yet, because they breed continuously and in large quantities they continue to survive.
What evolution isn't:
a) Adaption to specific environment or criteria. Unless you believe that God (or other supreme diety type) is controlling or influencing the process there is no specific adaptation or even adaptive trend (if you DO believe, that's cool too as we definitely tend to find more benefital changes than non). Evolution is quasi-random changes in the genetic code (chemistry) and has no intellect by which to try or plan an adaptation or even know what one is. Changes... happen. Literally anything can be tried. Most fail - usually immediately as they are non-viable (still-born or such) or within several generations. Eventually something survives that is different - which may or may not have any relevance to the environment the creature exists in. It is only through our perceptions and need to find purpose and order to the universe that we 'see' a pattern or reason out an 'advantage' when actually ANY change might work. Instead of say, growing a long neck to reach the tastely leaves in tree-tops (like the giraffe), a creature might instead develope the ability (or just have the ability to learn) to climb the tree instead (like some goats) and be able to reach the same leaves. This example also demonstrates another aspect - the long neck of the giraffe, while enabling it to reach those leaves, is actually an evolutionary DISadvantage; it makes them much more vulnerable to injury and certain diseases than other adaptations that would have allowed the same benefit.
b) Changes to make a 'better' or 'more competitive' creature. Yes, this CAN happen, but usually it is not the case. Again, there is no plan and the ONLY requirement evolution has is 'Can you viably reproduce before you die' (and even the death part is fairly flexible as the situation of the male praying mantis demonstrates). Often the 'better' branch of a species goes extinct because of totally random, temporary events (floods, fires, volcanoes, disease, drought, famine, etc.) that happens to hit the 'prime' habitat area that they had pushed the 'less competative' branch out of, thereby inadvertantly perserving the 'inferior' version. What might seem like an advantage today can be a huge disadvantage tomorrow. The cheetah is a good example in this case: it has evolved into a 'dead-end' - it is going extinct and not because anything man or the environment has done; it's own genetics and adaptations are causing a rising infant mortality rate and decreasing breeding rate that is not naturally reversable (and probably not scientifically reversable).
So.. back to humans. First off, let's look at some things we KNOW:
a) About 500 years ago, the average height of a human male was only slightly above 5' for most of the world. Around a 1,000 or so years before that, it was in the mid 4' range and around a 1,000 years before that it was around 4'. We know this because of buildings, remains, suits of armor and almost limitless other records. Some have said, "Well, it is because of diet - they didn't eat as well" - but this is incorrect. Many actually ate *better* than their modern contemporaries (especially in those locations with chronic food shortages), plus the rich/rulers of *every* civilization were able to dine on fruits, vegatables and meats (often to unhealthy levels)... yet they were no taller than the peasants/peons. Considering that the average today for most of the world approaches 6', that is a FIFTY PERCENT increase in size for humanity.
b) Both by funarary masks (masks made from a mold of the dead person's face in some cultures), skeletal remains, and artwork (from those periods and places that practiced 'realistic representations') we can also see that the common features for humans have changed as well - facial features tend to be more prominant and defined in modern man than those of the same peoples 1,000 or more years ago. This is a change that can be noted across racial and cultural lines as well.
... there are other changes as well, though most are more subtle. In any other organism, we would have long since declared modern man to be of a different species than ancient man (much less primative man) because of these physiological changes - but (I am guessing) due to our egotistical view of ourselves we continue to believe we are some sort of 'apex of evolution'. We're not.. we are changing and will continue to change. From a scientific standpoint, this is probably a bad thing since we strive so diligently to preserve the life of every human regardless of how diseased, deformed, impaired, or whatever they may be and continue to bring those genes back into the gene pool.
