Humans have a tendency to think of themselves as distinct from the other species, special, unique. Is this thinking correct in respect to Darwinian selection? Are we above other creatures when it comes to selection? Some scientists think that the Darwinian views of natural and sexual selection do not apply to us since humans are extremely”ecologically flexible”, meaning that we have the capacity to adapt to several types and changes of environment in ways that no other creature can. But, genomic information has provided the scientific community with evidence that selection of phenotypic traits does happen in humans. This means that selection does act on humans, even if the scope where it acts is not fully understood. This topic is of repute in the area of human evolution. Are humans still evolving, or is our species stagnant and unable to develop further?
Natural selection is the process described as the choice of biological traits based on the sexual success of people carrying these traits. In other words, the”passing on” of certain traits is determined by the reproductive success of the individuals. Sexual selection is the concept that animals develop certain traits or characteristics that aren’t necessarily crucial for their survival but give them a greater likelihood of reproducing, by way of example the mane of a lion, or the tail of a peacock.
Scientists have a good grasp on the roles sexual and natural selection play in most animal populations however, because of lack of suitable datasets, selection in human populations has not yet been fully understood. A study, conducted by Alexandre Courtiol and Virpi Lummaa from the University of Sheffield, looks at whether or not natural and sexual selection took place within this human inhabitants and extrapolated their findings to modern human populations. The analysis consisted of analyzing the chance for selection based on 4 factors in human life: achieving reproductive age, access to opposite sex, successful mating and fertility. They took into account the gap that wealth and gender would have on these points and divided the data into two groups: landowners and landless. This was done to exclude social status as being a cause for greater reproductive success. They found evidence that both sexual and natural selection acted on this population.
Natural selection was seen by the variance in fitness throughout the population concerning survival into adulthood and fertility. This is to say, people able to live to adulthood and pass on their genes were better adapted than individuals not able to do so, and therefore chosen more often from the opposite sex.
Variance in mating success explained the greater variance of male reproductive success, in contrast to females. This higher variance of male reproductive success can be explained by the social situation of the moment. Divorce and adultery were highly prohibited and only in the eventuality of a spouse dying would one be able to remarry and continue to have children, continue to reproduce. Men remarried more often than women since women were open to marrying guys much older than themselves. Reproductive success would be higher for men as a consequence of the fact that men have a longer reproductive life; there’s no age limitation in guys for the ability to procreate. This isn’t typically seen in cases where the spouse is widowed. Once widowed, most females wouldn’t procreate again; they’d stop to have reproductive success. The sexual selection observed in this population can be simply explained by the capacity of men to replicate for more; this does not give them greater fitness.
At this point it has been observed that natural and sexual selection acted on this human population. However, the question remains: to what extent? The results of the study further demonstrated that it was sexual choice that provided the higher proportion of opportunity of selection. In other words, that sexual selection accounted for a higher proportion of the total selection. Natural selection was still significant, but not to the exact same degree.
The novelty of the study is that it reveals higher chance of selection than any other research with human populations. Procedures such as statistics of birth and death rates, and demographic surveys don’t account for differences such as economic status, biological contrast and social status. This study does.
Are humans above other creatures when it comes to choice? Assessing the data, Courtiol et al. found that the human population followed the identical intensity of Darwinian selection as that expected from any other animal population. This means that humans in this population were subject to the same forces of selection due to any other animal inhabitants. Extrapolations can be reached from this analysis. This monogamous population showed both sexual and natural selection to the extent of additional animal populations; would a more modern population show the same degree of selection? The changes in social behaviour, technology, and culture appear to have not removed the evolutionary pressures of natural and sexual selection. If Darwinian selection operates in a strictly monogamous society then it’s plausible that it would also operate in a less monogamous population.
It is true that a lot of work has to be done in this field; however, new studies are being designed and carried out that promise to bring forth more info. It’s exciting to think that scientists are delving into these questions. Are humans unique in the view of natural and sexual selection? Does our”environmental flexibility” set us apart from all other animals? It’s my opinion that sexual and natural selection definitely play a part in our societies, but to what extent I remain unconvinced. Similarly to all humans, I enjoy being different from all other species.