Process of Natural Selection and Sexual Selection

Explain, with examples, how the process of natural selection and sexual selection are thought to have contributed to modern-day human behaviour. Lifestyle and behaviours of early humans would have been considerably different to that of modern day humans; however this is not an aspect that happened overnight but something that has taken thousands of years to develop. This aim of this essay therefore will be to explain, with examples, how human behaviour has evolved over time through the aspect of natural and sexual selection and how this has contributed to modern-day human behaviour.

Evolution is a “process over time which enables us to adapt to our changing environments”. Charles Darwin was one of the founders of this theory whereby he identified that rather that a species being fixed at creation they gradually evolve from that of their common ancestors (Darwin cited in Clegg 2007) with characteristics and behaviours, that best suit the ever changing environment we live in, being passed down the generations in order to support survival.

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The process in which these characteristics are passed down in that of ‘selection’ whereby certain characteristics are either evolved due to them conferring some advantage on the individual or eliminated due to them being disadvantageous within the particular environment (quote). Therefore genes that are less well suited to the environment have a lesser probability of being passed on. Selection is divided into two parts the first of these is that of ‘Natural selection’.

This is a ‘process whereby physical and behavioural characteristics which enable survival are passed on to descendents’ (Clegg, 2007, p. 121). It is a process in which genes, that are best suited to the environment we live in to ensure survival, have been passed onto the next generation and those that are successful go through a process of ‘adaptation’ in which the gene evolves by being gradually added to and modified in order to suit the ever changing world in which we live (Clegg 2007).

This process is seen as ‘survival of the fittest’ whereby the best suited characteristics are passed down to ensure survival of the related genes. This can be measured through the genes reproductive success whereby copies of genes can be identified by observing behaviours that are comparable in a range of cultures. One example of a behaviour that has been passed down many generations and can be seen across a range of cultures is that of cooking, a characteristic that arose around 1. 9million years ago (University Of Minnesota, 1999) within Homo erectus times whereby food items, rather than being eaten raw, were cooked by roasting them on fires.

Cooking is and aspect that has been essential for human survival and something that is seen by a range of researchers such as Wrangham (2009) to have played huge part within “our evolutionary success…as the digestive track shrank and brain grew”. It is clear that cooking has been passed down through many generations and therefore, in natural selection terms, this gene has excellent reproductive success.

However it must be queried as to how much of this is passed through genes and how much of this is taught through social interaction something that has been addressed by psychologists in which they believe that “there is a genetic predisposition underlying transmission across generations” (Clegg, 1999, p. 111) therefore they see genetics and social interaction as working hand in hand in which individuals may have been passed genes with a range of characteristics but it is essential for social interaction to unlock these genetic skills and behaviours.

The second type of selection is that of ‘sexual selection’ seen by theorists as “a special type of natural selection that is concerned with an organism’s ability to successfully reproduce” (Walsh 2000). Natural selection and evolution is reliant on this type of selection as “genes survival is not guaranteed unless reproduction occurs” (Walsh 2000). The majority of this theory is based on the fact that a woman’s fertility changes over time where as men’s fertility stays the same. Something that is thought that to be a huge contributor to the fact that men often find

younger more attractive women especially appealing to gain maximum offspring and therefore gene reproduction. Where as, due to the fact that females have a relatively small timescale to produce offspring, women have to be more choosey in their mate selection to gain “maximum quality offspring” (Kauffmann p. 4). It is seen by theorists that, since women are more selective in their choice of male, “intrasexual competition” (Kauffmann p. 4) occurs whereby males “compete for mates by intimidating or derogating same sex rivals” (Kauffmann p.

4). The aim of sexual selection, therefore, is to equip individuals with the types of behaviour that will attract mates and maximise reproduction and is often based on characteristics that women are drawn to such as humour. Humour is a common factor in all humans that appears at around 4 months of age. It is a “positive emotional expression” that we all have the capacity to respond to and is the “results of complex psychological adaptions whose primary functions were to attract mates, yielding reproductive rather than survival benefits”.

It is through humour that males compete for female attention by making fun of and belittling their rivals so they become top dog and become more appealing to women. It is also identified by Kauffman that “humour is a valuable index of genetic fitness since high quality humour cannot be faked”. Although this theory presents with some interesting ideas it does portray a rather idealistic view of the world in which male meets female, offspring is produced and genes are passed down.

However within the real world there are features within society that raise doubt to this theory such as homosexuality, individuals who choose not to have children and those that meet partners later on in life all of which are either unable, or unwilling to produce offspring therefore if survival of the gene is the most driving factor within the selection process why would these incidents occur? This essay has explored evolution and explained the importance of natural and sexual selection within this.

It has been identified that natural selection is based on selection of behaviours that enable genes to survive and evolve, such as cooking, and sexual selection is based on selection of genes that enable the attraction of mates such as humour. However it is still important to raise the issue of how much genes contribute to behaviours that are seen as being learnt through social interaction and how sexual selection takes into account those individuals who do not reproduce therefore preventing their gene survival.