Humans have not stopped changing. Human populations continue to vary and change, with various forces at work causing this variation.
At the base of all this change is the Bio-Cultural approach. This approach tries to understand how variations of human biology reacts to culture and their interplay. This can include culture, technology, food, religion, traditions and so forth. It is basically the biological reactions to different sources of culture. One way in which humans are still changing in gene flow. Culture is changing the gene flow by facilitating and moving people and genes. As in the video, the example of colonialism was brought up. This cultural event has dramatically changed the genetic landscape of the countries which were colonized, as those colonizers brought their genes with them and shared and spread them around, looking much different if they had never colonized. However, culture can also inhibit and restrict gene flow. Culture, language, religion, age and economic status can all be deciding factors in deciding where that gene is spread. These often act as large barriers to gene flow.
Genetic drift is variation in the relative frequency of different genotypes in a small population, because of the disappearance of particular genes as individuals die or do not reproduce. Genetic drift can occur because of war, famine, culture, religion, or a number of different reasons. I thought it was interesting how the video brought up the example of the Amish. Because the Amish only mate within themselves and inside the Amish community, their genes are different from those without the same stipulations. As a result, the Amish are noticeably physically different looking from those who are not Amish.
Natural selection and survival of the fittest is also an example of how humans have not stopped changing. The effects of natural selections on humans depends strongly on the environment surrounding the person. As we learned, so many can go into the environment shaping human biology. Most specifically though, is disease. As we learned in some of the first lectures of the course, certain populations are more susceptible and resistant to certain types of illness and diseases. Many times, bodies build up defense systems over the years to the certain diseases environment if it is common and able to. For example, when colonizers came over to North and South America they brought their European diseases which were completely foreign to many natives living there. As a result, their bodies could not handle the disease and they died, while the European’s health was not severely compromised. Technology, especially when it comes to medicine, has also allowed human populations to continue to vary and change. Resistance to antibiotics as we often hear about with MERSA and others is an effect which has been building up for years. Medicinal technology also has advanced humans and even prolongs their lives when natural selection tries to set in. Although it may be hard to see from a human point of view, we are constantly changing and developing, just as all of those before us.