Analyze the effects of genetic drift on large and small populations
The smaller the population, the easier it is for random drift to drive alleles to fixation. In small populations, drift causes alleles to become rapidly fixated or lost. In the largest population, genetic drift is far weaker
Bigger impact on smaller populations while a smaller impact on larger populations
Explain how drift and selection can interact(happen simultaniously) during founder events to cause newly formed populations to differ substantially from their source population.
Impact of selection can override the impact of drift
A lot less alleles in the population
Founder event--when a population leaves and starts a new population (becomes the determining population
They are the new norm and the only ones in the population
Huge change in the allele frequency due to the founder event
New natural selection.
Compare and contrast the kinds of knowledge that can be gained from laboratory versus natural studies of E. coli
In the lab you can control all the variables and watch and store every generation to capture all the changes that happen. This lets you have all the knowledge. Studies of E Coli in nature would produce more random(even though end result is that fitness will survive) and incomplete results
In the lab, a certain gene was turned on and then they were able to look back to when it happened.
In nature, its random.
Demonstrate how deleterious (causing harm--think “delete”) mutations can exist in a population
Hard to get rid of something that is completely genetic- dominant and recessive traits could be passed on through heterozygotes and
Recessive traits are usually deleterious that can be masked and pop up every so often – diminish over time
A lot of mental and cognitive disabilities come from deleterious mutations, we can see these in the population Cri-du-Chat specifically (deletion of genetic material on the short arm off the chromosome.)
Sickle cell anemia, while it is deleterious in most ways, it is still protected from malaria so it is beneficial is some parts of the world
Mutations= harmful, beneficial, or neutral. (random)
Describe the differences between directional selection and stabilizing selection
Stabilizing is where you lose diversity and stabilize around a common particular trait (eliminates the extremes, middle is favored) ex. Birth of babies and weight.
Directional is the shift from one extreme phenotype to another, the first shrinks the normal distribution whereas the latter shifts the mean from left to right. Ex. black and white moths.- a mode of natural selection in which a single phenotype is favored, causing the allele frequency to continuously shift in one direction.
Illustrate how selection and heritability (the ability to pass on traits and how easily they are passed on through generations) affect the speed of evolution.
Selection requires that traits are heritable, if there is no selection, heritability doesn’t matter. Heritability is fact and selection is what is being passed down. Selection is the pressure and heritability is the action, together they create diversity and fitness in populations to continue genes through generations showing evolution through time. These two things make evolution possible, thus having a big impact on the speed of evolution--speed up the process of evolution