Homo sapiens have definitely not completely evolved. If we consider that we have changed significantly since our ancestors walked in Africa, we can attribute our phenotype and genotype to a number of factors. Obviously, we have undergone natural selection as various traits became advantageous with respect to our environment and ongoing way of life. Our brain size and associated abilities allowed us to use effective communication to develop advanced culture. Random mutation played a part in these ongoing changes, but since we evolved over hundreds of thousands of years it seems like selected traits played a greater role. We are who we are due to the ways in which our ancestors coped with their environment and migrated across the globe.
Our continued evolution may be focused differently than ever before. If you consider that advanced countries have become more sedentary and exercise has developed a recreational purpose, this could lead to changes in our bodies if this trend was to continue over generations. We might select for larger feet to improve the stability of larger bodies and possibly even need more cushioning to allow us to sit for longer periods of time. It does not seem that our environment is selecting for physical changes. We have clothing, housing, transportation, and 20 aisles of food at Meijers so I do not think we need to develop hairy coats, larger canines, or better grasping to move back into the trees. Even our vestigial parts like the coccyx and appendix have not completely disappeared even though they have not served a meaningful purpose during recorded history. As our life expectancy has increased due to improved medical care, people are experiencing diseases that were not problematic when people died at an earlier age. Cancer, heart disease, and infections due to bacteria or viruses are becoming more important when considering the genetics of our immune systems. Even though our diets are not heart healthy and some environmental factors increase the prevalence of cancer, it is possible that our immune systems could battle these problems given ample time. Man may not be willing to wait for our bodies to find a way to defend against these problems over the next thousand years.
Our future evolution may be very different. We are no longer dealing with predators and seeking shelter in caves. We rely on microwaves and convection ovens instead of struggling to make a fire. The pressures that challenge us today revolve around infection and disease that have become major killers of Homo sapiens. If we consider that our past evolution has changed our genome creating our present chromosomes, the current ability to cut and splice our genes may govern our future evolution more than natural selection or mutation. Removing or replacing genes has previously required thousands of years, but today a permanent change might be made overnight. I fear that changing our genome before our bodies are exposed to generations of environmental stress may lead to phenotypic disadvantages that have not been anticipated. I hope our governments and scientists can agree on a reasonable course to take that allows a safe path to treat disease without upsetting thousands of years of mutations and natural selection. Survival of the fittest might become survival of the most manipulated.