Question

First of all, let me apologize for my amateurishness. I have no background in biology. Please bear with me.

My question relates to sexual selection, or specifically its most prominent manifestations:

competition among males which is resolved through male conflict
competition among males which is resolved through female decision
Let us postulate the traits that these two forms of selection might bring about, e.g., strength for the former case and attractiveness for the latter. Of course this may vary. Would I be right to say that whether this trait is passed on through the Y chromosome or whether is it passed on somewhere else (and therefore to both male and female offspring) is a question of probability? If so, what do the odds look like?

The aim of my question is really to understand how selection among men has changed the human species in general. It is well-known that aggression, charm, and paternal care are some traits that have evolved among men. But how would we go about measuring the impact of this selection upon the gene pool of the entire species?

Lastly, is there any literature based on evolutionary research that concerns my question in particular?

Answer 1

Sexual selection, impacting reproductive success, can lead to the evolution of secondary sexual characteristics that are passed through the gene pool, with traits linked to genetic fitness favored for inheritance. Studies in genetics and evolutionary biology investigate the frequency of these traits and their impact on human evolution, considering both genetic variance and sexual dimorphism.

Step-by-step explanation:

Understanding Sexual Selection and its Impact on Human Evolution

Sexual selection is a component of natural selection that Darwin identified as playing a critical role in shaping species through reproductive success. It comes in two forms: intrasexual selection, involving direct competition among males (or females) for mates, which may select for traits such as strength or aggression; and intersexual selection, involving mate choice, which may favor traits like attractiveness or elaborate mating displays. Traits developed through sexual selection, such as a peacock's tail or male birds' plumage, are known as secondary sexual characteristics.

The transmission of these traits through the gene pool depends on their genetic linkage. While it’s possible for a trait to be carried on the Y chromosome and thus only passed from father to son, many traits favored by sexual selection are not limited to the Y chromosome and can be inherited by all offspring regardless of sex. The good genes hypothesis supports the idea that traits indicating genetic fitness, including metabolic efficiency or disease resistance, will be selected by females and passed down to offspring, potentially explaining the persistence of such traits within a population.

To understand the impact of sexual selection on humans, researchers study the genetic variance within a population, the emergence of sexual dimorphisms, and how certain alleles influence reproductive success. Studies can quantify these effects in terms of allele frequencies and phenotypic expressions over generations. Literature on evolutionary biology, genetics, and anthropology contains research related to this area of inquiry, although examining sexual selection's role in human evolution is complex due its interaction with numerous environmental and social factors.