My understanding of evolution is that everything started from something and throughout time it changes and becomes more diverse than the generations before it, some examples of evolution are apes into humans or fish into frogs. I now know that evolution is much more than just something changing into something else, to be completely honest I believe that first statement is only true to an extent. Instead of apes directly evolving into humans we know that we share common traits and are similar in structure to apes. Evolution can occur on a large scale or small scale depending on what’s being changed.
Natural Selection, a form of evolution, was brought up by Charles Darwin in one of his writings. Natural selection is the idea or theory that organisms that are better adapted to their environment tend to survive and produce more offspring than an organism that can’t adapt as well. The variation in these organisms’ genotypes are passed on from generation to generation at the expense of ones that are not of high value to their survival. Adaptation is a part of natural selection, it is the process of organisms becoming more fit for its environment. For an organism to have the best chance to survive it must adapt to its environment in every way possible.
Following up with natural selection I now know that there are three requirements for natural selection to occur, Variation must be present, Heritability and differential mortality. Natural selection can also operate in three ways directional, stabilizing, and disruptive. Directional selects one extreme weather its for or against it, an example of directional selection would be giraffe necks being long so that they can eat leaves off trees. Stabilizing selection favors the average individuals in a population, an example of this is birth weight in humans, of a baby is born at an extreme weight weather it be over or underweight they are at risk. Disruptive selection means extreme values for a trait are favored over intermediate values. An example of disruptive selection is the London peppered moths.
Another form of natural selection is sexual selection which includes female choice and male-male competition. Female choice includes resource based, genetic quality, extreme choice and male-male competition includes fighting, sperm competition, and male guarding. Resource based choice by females is when a female chooses her mate by the resources, he has to offer these can come in different ways such as gifts or the ability of the male to take care of the offspring. In genetic quality a female chooses her mate based on the genes that the male has to offer so that her offspring can survive. Extreme choice by females is when males cluster in places that a they are more likely to find a female to mate which will draw females in.
Male-male competition is pretty much self-explanatory, fighting is when males literally fight over a female. Sperm competition is when a male reduces the chances another male can have their sperm fertilize eggs. And mate guarding can be literally guarding your female mate or things such as insect penis plugs.
A population that is in equilibrium is a population that doesn’t show changes in the frequencies of the its alleles from one generation to the next. The equation for the equilibrium is p²+2pq+q²=1. To figure out these you can use these formulas to find p and q, p=p²+o.5pq and p+q=1. p also equals the homozygous dominant and q equals the homozygous recessive while 2pq is the heterozygotes.
Mendelian genetics also applies to natural selection and evolution. Mendel used pea plants to introduce his new theory of inheritance. The work that went into Mendel’s theory was done before the introduction of meiosis. Most of his work went unnoticed or ignored for a period because all of it was mathematical. Mendel identified traits that were true breeding meaning that the offspring have the exact same traits as the two parents that mated. In Mendelian genetics the first generation is known as P for parental, their offspring are labeled as F1, next you have F2 which can be a cross between two F1’s or a cross between a P and an F1.