In this post, we’ll unpack all you need to know about Sexual Selection, defining exactly what it is, the science behind how it works and more.
What Is Sexual Selection?
Sexual Selection is a form of Natural Selection where individuals select mates based on certain traits which leads to the evolution of those traits over time.
“Nothing in biology makes sense except in light of evolution.” ― Theodosius Dobzhansky
Sexual Selection Versus Natural Selection
Sexual Selection is the evolution of qualities that enhance reproduction. Natural Selection is the evolution of qualities that enhance survival.
The Science Behind How Sexual Selection Works
Within any population, individuals possess a range of reproductive traits that affect their ability to attract a mate.
Individuals with traits that increase reproductive success are thus more likely to reproduce. As a result, these advantageous traits succeed in being passed on to the next generation and thus become more common.
Individuals with traits that decrease reproductive success are thus less likely to reproduce. As a result, these disadvantageous traits fail in being passed on to the next generation and thus become less common.
Sexual Selection can lead to the evolution of pronounced differences between males and females of the same species, known as sexual dimorphism. Male sexual selection is driven by female mate choice. Female sexual selection is driven by male mate choice.
Adaptations
An adaptation is a solution to a problem posed by survival and reproduction.
Problems that adaptations allow us to solve are called adaptive problems ― problems of survival and reproduction. Thus, without solving adaptive problems, we would not be able to survive long enough to reproduce successfully.
Mutations
Mutations are changes in the structure of the molecules that make up genes, called DNA. They are either harmful, neutral or helpful.
Mutations can either occur randomly ― for example when replicating cells make an error while copying DNA ― or in response to the environment ― for example radiation.
Genes are pure information. Only genes that do enhance survival and reproduction in a given environment are passed down to future generations at the expense of those that don’t.
Summary (TL;DR)
Sexual selection is the evolutionary process by which certain traits become more prevalent in a population due to their role in enhancing an individual’s reproductive success.
Traits that increase an individual’s ability to reproduce are selected for and increase in frequency. Traits that decrease an individual’s ability to reproduce are thus selected against and decrease in frequency.
