Aubree's Evolution Blog

Δp: is defined as s*(pq).  s: This is the selection coefficient. This is used to measure the advantage of an individual carrying a certain allele. In my example s is 0.02. p: this is the frequency of the allele q: this is the frequency of 1- p. 

 The Hardy Weinberg Equilibrium states that a populations allele and genotype frequencies are constant , unless there is some type of evolutionary force acting upon them. This equilibrium also assumes that there is no selection, no mutation, no migration, a large population, and random mating.  This figure shows the HWE equation.   Problems from class: In dwarbs the allele for a black tongue is recessive. In a population of 800 dwarbs 25 have black tongues.  1. what percentage of the population has black tongues? 3.1% 2. what are the frequencies of the dominant and recessive alleles? dominant: 0.824 recessive: 0.176 3. what percentage of the population are heterozygous for this trait? 29% The delta-32 mutation, a recessive allele, gives humans protection from HIV infection. The frequency of this allele in a certain town is 20%.  1. what percentage of the population is homozygous for the allele conferring HIV immunity? 4% 2. what percentage of the popul...

  When I began college I had so many misconceptions about science in general. Mostly I thought I knew a lot of the details about different scientific events and boy was I wrong. It was not until that I took Genetics last semester that I really learned about mutations. I did not know that there were so many different types of mutations that can happen in the body and I was surprised to learn that mutations can be silent as well. I also thought I knew everything about the central dogma. I also learned in genetics just how complicated that each step of the central dogma gets.  Through college it has mostly been very gradual learning and connecting different scientific ideas for me. I feel like I do not have that many "AH-HA" moments. Each class that I continue to take adds onto ideas that I have learned previously and concepts start to increasingly make more sense in my head. Genetic drift is always something that I have...

  Kin Selection is defined as when an organism favors the reproductive success of their own relatives even if it doesn't come at a benefit to that organism.  Altruism is defined as actions of an organism that benefits the fitness of another but is costly to the fitness of oneself.  I think that Kin selection and altruism can go hand in hand. I would say that kin selection is altruistic because there is an act to benefit another and not benefit oneself. Hamiltons rule is when a ltruism is favored by natural selection.    Hamiltons Rule shows: r B > c where r is the relatedness, B is the benefit of the recipient, and c is the cost to the altruist 

 One example of micro evolution occurring in the last 50 years is the beak size of the soapberry bugs. In Florida the soapberry bugs had long beaks so they were able to reach into deep seed pods from a certain type of tree. There was then a species of tree that was introduced that had smaller and shorter seed pods. These shorter seeds where soon very populated and the soapberry bugs fed on these trees. Over generations the soapberry bugs began to have shorter beaks. This was due to natural selection because the bugs did not need the longer beaks in order to feed.   

  This drawing helps me to understand what paralogs and orthologs are.  In the picture above the mouse, human, and frog all have the same beta or alpha gene from their common ancestors. Orthologs are the same genes in a species that come from a common ancestor. So in the picture above the mouse, human, and frog all have the same beta or alpha gene from their common ancestors. Paralogs come from a duplication event in which there is a different function of the gene that is formed. The beta mouse and the alpha mouse are paralogs because there was a gene duplication early in the lineage and now the genes have two different functions (alpha and beta). 

 A phylogenetic tree is a diagram that represents how life on Earth is all connected to one another. It is called a tree because the diagram looks like a tree. It looks as if it has a trunk and branches. The trunk of the diagram represents the first common ancestor from the group of organisms that are being looked at.   There are a few different types of phylogenetic trees and today we are going to look at 2 different types, monophyletic and paraphyletic.  There is an example of a phylogenetic tree below. You can see at the left side of the picture that there is a trunk and the diagram extends into branches. This diagram is showing how water living creatures are related to one another.  This tree is a monophyletic tree. All of the groups connect at a point somewhere on the diagram. This shows that they all have a single common ancestor.   This phylogenic tree is a paraphyletic tree. A paraphyletic tree shows how a group of organisms are related but it leaves out...