Week 13 Sexual Selection

Sexual Selection

Natural selection is not the battle to survive, but the battle to reproduce viable offspring. This high need and battle to find a mate and produce offspring leads to sexual selection. If the main goal is to produce the most, or fittest offspring, animals need to be choosey with whom they are mating. Just as natural selection allows the most fit alleles to be passed along and the least fit to die, sexual selection makes certain traits more or less common due to their ability to find or attract a mate. 

Everything is a delicate balance of trade-offs in evolution. For the process of mating and producing offspring, each sex has their own challenges. For the females, it takes a great deal of energy and resources to create and carry offspring. For the males, mating does not require nearly as much energy. Because of this dichotomy, females are typically the ones choosing who they will mate with. If they are going to use that much energy to produce this offspring, then they want to choose the best mate to pass on the best genes. For the males, they want to stand out to attract a mate, many do so by having ornaments, such as big feathers, or brighter colors. While these traits might attract them a mate, they are also being made more visible to prey, or perhaps less agile due to the nature of their ornament. It is the job of the female, oftentimes, to determine the best balance between looks and survivability. It is also more common than not, that the female species have less gametes, or sex cells, than males do, allowing them to be in more control choosing their mates. 

Generally, sexual selection tends to act more on males because of the dynamics of competition, reproductive strategies, gamete availability, and the energy imbalance when producing offspring. 

Looking at this image, the birds become increasingly ornate from left to right. If the extra colors and headfeathers are not a hinderance to them physically, this might give the far right bird an advantage over the other two. If having bright colors or headfeathers makes them more visible to predators, then a female might be more inclined to mate with the bird on the far left, as their offspring might have a higher chance of living. Depending on the ecosystem, surrounding populations, strengths and weaknesses of each species, each of these birds could be a frontrunner in sexual selection. Learning about sexual selection just proves how intricate and important both natural and sexual selection truly are. What I have learned about sexual selection, further supports the ideas I have learned about natural selection and the patterns and tendencies that support it. I think moving forward, I would like to learn more about how there are upper ends of "good traits", how sometimes too much of a good thing can be a bad thing. If there is such thing as over evolution of a trait and seeing how that affects sexual selection, and the gene pool.