Week 14 Advantages of Sexual Reproduction

Advantages of Sexual Reproduction

    There are two forms of reproduction: sexual and asexual. Sexual reproduction is the combination of the gametes from two parental organisms, while asexual reproduction produces offspring from one parent, that are genetically identical. While both processes are vastly different, they each have drawbacks and advantages. 

    Sexual reproduction requires much more energy because it involves several resource-intensive processes. These include finding and attracting a mate, producing gametes (sperm and eggs), and often investing in courtship behaviors or physical displays. Additionally, after mating, there may be further energy spent on nurturing and protecting offspring. In contrast, asexual reproduction only requires one organism to produce offspring, without the need for a mate or the complex processes associated with sexual reproduction, requiring much less energy. Asexual organisms also oftentimes have very large reproductive output, which is particularly beneficial in stable environments where adaptation is less critical. The diversity offered by sexual reproduction is extremely beneficial because it increases the likelihood that some individuals in a population will have traits that help them survive and adapt to changing environments. If there are unfavorable genes in an organism in a population with a lot of diversity, the entire population is not at risk for extinction, as the more fit organisms can continue to survive. This gives populations a higher chance of surviving a negative mutation. In contrast, asexual reproduction results in genetically identical offspring, which means the entire population is more vulnerable if a negative mutation were to arise or if there was an extreme change. This lack of diversity limits the adaptability of asexual organisms over time.

Here we can see the upper dots are the parents and below them are the offspring they produce!

    

    Sexual reproduction shows its advantages over asexual reproduction in many ways, including the Red Queen Hypothesis. This states that organisms must continuously evolve and adapt in order to maintain their current fitness relative to other evolving organisms. Like I mentioned previously, asexual organisms cannot continuously adapt or evolve, since their offspring's genome will be identical to the parent's.

    Heterozygosity is having two different alleles of one gene, meaning it has a wider range of genetic traits to pass on to its offspring. For example, if a gene has a version for brown eyes (B) and a version for blue eyes (b), a person with one of each (Bb) is heterozygous. This is an advantage because it increases genetic diversity, which improves the chances of survival and adaptability in changing environments. I took genetics last year with Dr. Wiggins and I loved being able to see how one of the foundational concepts of the class supports what we are discussing in evolution so well!

    Parasitism is a relationship in which a parasite experiences benefits at the expense of it's host. I was surprised to learn that there are many types of parasitism and parasites. I always viewed it as an organism living inside of another organism, making it sick and giving the host viruses. Doing further research, I was further informed that birds can be parasites - by laying their eggs in other nests. Although this does not fit the typical mold of parasitism that we imagine, the bird trying to hatch these eggs is now having to care for one more egg which will ultimately cost it more energy. This is benefiting the parasite bird and harming the host!  Evolutionarily, if a host is being negatively affected by a parasite, if it reproduces asexually, its offspring are going to be disadvantaged. If the organism reproduces sexually, 50% of it's offspring's genome will be coming from another organism, which could overrule the potentially harmful genes from the host.