Entry #3: Sex Ratios and ESS

The ESS concept stands for Evolutionarily Stable Strategy. Dawkin states that this type of strategy is a strategy that if most members of a population adopt it, cannot be bettered by an alternative strategy. The reason Fisher stated that a sex ratio of 50:50 (males:females) is an ESS is because he said that it will counter any bias. If there was a gene that was bias towards a certain sex, then the others would have lower mating success just as Fisher states. But, selection will go in the other sexes favor, making sure the ratio will stay balanced again. I believe that the autosomal chromosomes and the sex chromosomes will both favor a 50:50 ratio. Both males and females need the autosomes and the sex chromosomes to become a full human being. The autosomes are the first 22 pairs, which both males and females need so there is no competition needed, and the sex chromosomes which is the 23rd pair, is needed in both males and females. The only difference is the sex chromosomes determines the sex of the male or female. The only competition here is whether or not the chromosome will be XY or XX. The cytoplasmic elements are not a 50:50 ratio. Some elements are used more than others, but this cannot be helped since every element has a certain job it must do. Such as the mitochondria which makes ATP, it will not compete with the endoplasmic reticulum because it has no reason to take its job. The chromosomes are different from the cytoplasmic elements in that they determine the make up of a human being and the cytoplasmic elements help to keep them running. Therefore there is no reason for the cytoplasmic elements to counter each other if the ratio is not always 50:50.

Entry #2: Major Transitions in Evolution

Mayhew proposed that sex was a major transition and so he goes into the whole process of meiosis and the way it works. He also talks about autotrophic and heterotrophic origins of the biosphere. Dawkins proposed and talks about DNA and replicators that competed for these 'building blocks'. He then proposes that the replicators that survived are the ones that made 'survival machines' to live in. These survival machines are what multicellular organisms are. Both Dawkins and Mayhew talk about DNA and they both talk about the way an organism is made up when two organisms have sex and the process that takes place internally on a molecular level. The differences between these two is that Mayhew talks about recombination and the different processes that may have favored it and he also talks about mutations that can occur which affects the genes of an organism. The scenario that is most likely when choosing between the heterotrophic and autotrophic theories on the origin of life is the autotrophic theory. The autotrophic theory makes more sense on a scientific level and seems like there was more thought put into how replicators became multicellular organisms. The fact that the autotrophic theory has many reasons for why it had taken place also makes it a better and more believable theory rather than the heterotrophic theory. It can be very so that a prokaryotic cell had lost its cell wall in order to engulf large organic particles.

Entry #1: Domestication

The problems with this argument that Darwin identified is he says that domestic species are not different when it comes to their genes. This could not be true because many of the domesticated species of today look nothing alike. There are now many different types of breed of dog. They may have all come from one specific type of dog but the genes have changed as more and more different species were bred. Darwin also says that some races have been modified by other different crosses. I believe that the domestication process may have started out with just one type of species of dog but grew as more and more different species were discovered.
On a genetic level, you could look at the different variation of the genes and the genetic make up of the animals. A mutation, which is a rare gene that is inherited could also cause the different breeds of dogs that we have today. Many of the crosses between the different types of dogs could somewhere in between contain a mutation. Another reason could be because of epistasis which is where a gene influences the expression of another genes phenotype.
Dawkins says that the "survival of the fittest" is an organism that will sacrifice itself when needed to save the species as a whole. He is implying that the species that are not being selfish will survive.
Ecology plays a role in the domestication of the dog because the dogs that were isolated from the wild dogs may have been easier to domesticate.