Natural Selection Vs Human Evolution

Evolution is the changing of gene frequency in a population over time.
Natural selection is where animals with advantageous characteristics produce more offspring, therefore passing down favoured genes. In the more developed parts of the world, medical care and access to food means natural selection is lesser, as selective forces that were there before e.g some diseases and predators, are no longer there. Therefore, some humans that have characteristics that would have previously meant they produce less offspring, reproduce at a similar rate to humans with more advantageous characteristics.
However, in many parts of world selective forces leading to natural selection are still prevalent. Where easy access to medical care and food is not there,
natural selection does take place on humans, making them subject to evolution. Also, anywhere in the world where some humans have a higher reproductive rate to others, will lead to some form of evolution.
Even in western world, bacteria and viruses are evolving amongst us, therefore humans are evolving along with these, through natural selection. Evidence of humans being able to digest milk, and humans being born without wisdom teeth (no longer necessary in modern diet), showing humans are still evolving.
Evolution can still occur without the need of natural selection.
Evolution of humans can occur from mutations and migrations of genes and people. Genetic drift occurs when by chance, one human has more offspring then another, so their hereditary characteristics are passed on to more people, whether these characteristics be advantageous or not. These are then passed on further, leading to a ‘drift’ in the characteristics of humans, a part of evolution.
Behavioural evolution is the adaptation of behaviour rather than genetic adaptation through natural selection, to combat environmental forces. E.g agricultural advances such as keeping animals, leading to easier access to food. During Neolithic revolution when humans began to use agriculture for food production, rather than previous hunter-gatherer techniques meant selective forces on human evolution changed, as different characteristics became more desirable. E.g. the gene that helps digest starch is more prevalent in populations where agriculture was favoured.
Human physiology also leads to adaptation of many stresses. E.g. fat storage. However, if behavioural and physiological fail, rates of reproduction is effected, therefore natural selection does take place, and therefore
evolution.
The rate of reproduction of humans is much higher in less economically developed areas of the world such Asia, Africa and South America, whilst in more developed countries the birth rate is decreasing. Therefore, the genetic makeup of humans is shifting toward the genes held by the people from the countries with higher birth rate, causing an evolution of humans.
Humans may be evolving to have less favourable characteristics, as due to the availability of medical care, people who would have been unable to live and successfully reproduce do, leading to the passing on of genes that are seen to be disadvantageous e.g. people with diseases like cystic fibrosis are living to an age where they can have children, therefore passing on their genes and leading to evolution of humans to have less advantageous genes.
In conclusion, modern humans still subject to evolution, although selective forces have lessened in more developed areas. Natural selection still takes place when human behavioural and physiological adaptations fail. Different birth rates amongst groups of people means evolution of human race will continue happening. Advancements in medicine may mean humans are passing on genes that previously wouldn’t have been passed on. Evolution of humans takes place due to other factors like migration, mutation and ‘Genetic drift’.