The contemporary theory of evolution that is based on a spectrum of diverse evidence from the scientific field is widely accepted though contentious in a social context when applied to human beings. To date, the evolution theory has been applied to understand variation in human beings in multiple ways. The most infamous use had been used to justify theories of racism and prejudice. Nonetheless, archaeological evidence has demonstrated that all human beings share a common ancestor. Therefore, human display massive genetic unity in comparison to other species, which has in part resulted in many to assume that evolution demised with the origin of modern mankind.
However, the diversity that is exhibited within the human species remains to be answered. Is evolution still a driving force behind human diversity? Is natural selection behind the evolution of humans? Is human diversity as a result of genetic drift? When we think of human evolution, we look back to natural selection, it remains a common understanding that humans evolved years ago, yet research suggests that regardless of industrialization and modern technology human progressively continue to evolve. In this light, it should be noted that in an attempt to answer the questions researchers have shifted from attaching value to biological aspects to comprehending the underlying biological and adaptive mechanisms that control diversity.
With this regards, over the years humans have used multiple mechanisms to control, modify and adapt to the natural environment. Adaption in its simplest form is a mechanism that necessitates humans to mediate stresses in their environment to enhance reproduction and survival. While adaption can take place genetically, conceivably adaption can also occur as a genetic modification in behavior as a response to evolving environment.
For the most part, behavioral flexibility cannot accommodate change; as such humans have an array of psychological and physiological mechanisms that help them to respond to an evolving environment without the need for genetic adaption, for instance, adaptive changes in the rate of respiration, heart rate and fat accumulation in the body.
If the environment is evolving, certainly nothing remains static, humans are evolving faster than before from both dimensions, genetics, and environment. Part of the answers lies in our genes and the sequencing of the human genome. Scientists are able to compare genes from diverse human and exhibit how far we have evolved from each other. Dr Pardis Sabeti, a geneticist at Harvard University says that “We are living records of our past,” “And so we can look at the DNA of individuals from today and get a sense of how they all came to be this way.”
An obvious example is the skin color; we have evolved to have diverse skin colors with diverse skin tones. Another area of recent evolution lies in our metabolism. Research indicates that our metabolism has evolved with time to allow us digest food that we were once was unable to. Apparently, the gene that regulated humans ability to digest lactose, shut down about 10,000 years ago, before farming was even invented.
However, today the rate of lactose tolerance is different in diverse parts of the world, apparently higher in places that had histories of dairy farming! Perhaps strangest human evolution lies in the ability to withstand infectious diseases. Millions of people die each year as a result of infectious disease. Yet, some still survive and are more likely to evolve the gene to their offspring.
A good example is a susceptibility to HIV virus. Scientists propose that a variant in the genes of some individuals completely protects them against the HIV virus. This is evidenced in Europe more than it is in Africa. The origin of the variant dates to 1970s years before the AIDS epidemic. It is likely that this variant had been naturally selected, as such humans in these areas evolved protected against viral infections.