Are Humans Still Evolving?

Natural selection is a multi-stage process that leads to evolution and is described as the process through which populations of living organisms adapt and eventually evolve. Individuals in a population of the same species show genetic variation caused by random mutations, resulting in various traits either expressed through the phenotype or the genotype. 

These random variations may result in some individuals possessing alleles that produce traits better suited to the environment than others. Individuals with these advantageous alleles are more likely to thrive and in turn reproduce, passing down these advantageous adaptive traits to their offspring. Overtime, these become common traits in the population, causing a rise in competition for food and resources. This process of advantageous alleles determining the survival of a species continues, eventually resulting in evolution of the species from the ancestral species to its current version.

In accordance with Darwin’s theory of evolution, humans have evolved from an ancestral species. Having evolved most probably from apes over a period of approximately six million years, humans have evolved from numerous predecessors. Evolution in humans is evident because of our ability to walk on two legs (bipedalism) and the gradual increase in cranial capacity. 

Bipedalism, linked directly to the ever-growing human brain, developed as the increasingly intelligent primitive humans began to grasp an idea of how the world around them worked and began to respond and adapt to it . This type of anatomical and physiological evolution can clearly be seen in the preserved remains of early man, helping to identify rough areas of time where evolution may have occurred to produce modern-day humans (homo sapien sapiens). 

Some may argue that modern humans have stopped evolving. With cranial capacity having remained around the same size for the last million years, suggesting that the human brain has stopped growing in size due to there being no need for humans to use them as much with recent developments in technology.

However, there is stronger evidence for ongoing human evolution. Whilst previous forms of evolution may have been more phenotypic from the remains discovered, current forms of evolution in humans may be classified as more genotypic. Scientists have discovered that the total internal body temperature of humans has decreased from 98.6°F in 1868 (37°C) to 97.9°F (36.6°C) at present day, showing a decrease of 0.5 every decade. The evolution of the total internal body temperature may be due to our environment changing. Within the comfort of houses and aided by technology, humans no longer have to consistently struggle to survive. 
Furthermore, evidence for evolution in modern-day humans can be seen when observing humans from different continents. Those living in areas of the world with a predominantly vegetarian diet (Pune, India) have shown a higher frequency of the FADS2 gene. Allowing for a more efficient processing of omega-3 and omega-6 fatty acids from non-meat sources, it has allowed those with mostly vegetarian diets to effectively digest their diet. Moreover, humans have shown an increase in tolerance of dietary changes such as increased lactose intake or protection from infectious diseases as we have gotten more resistant to them.



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