Mechanisms of Evolution

Master the 5 Mechanisms of Evolution: drift, mating, mutation, flow, and selection!

The Five Fingers of Evolution Watch the video to answer the questions that follow. Click the blanks to complete the passage below. The gene pool of a population is the total number of alleles present in the population. Evolution occurs when the gene pool changes over time. There are five ways a gene pool can change over time these are referred to as the mechanisms of evolution.In the video the little finger represents genetic drift which involves a random event causing the gene pool to shrink. The ring finger represents random mating which can cause the gene pool to change if mates are chosen based on certain traits that they have or don't have. The middle finger represents mutations which can change allele frequencies by increasing variation. The pointer finger represents gene flow which causes changes in allele frequency as individuals of a population migrate. The thumb represents natural selection which involves the environment selecting certain individuals to survive based on their adaptations. Those individuals that survive are the fittest as they are able to pass on their genes to their offspring. Sort the items into the appropriate mechanism of evolution. Natural Selection Variation, more fit survive reproduce Genetic Drift Change in allele frequency due to chance Gene Flow Transfer of genes from 1 population to the other, could be due to immigration or emigration Mutation random change in DNA Match the examples to the mechanism of evolution they represent. A population of beetles experience an increase in the allele for dark coloration, though this coloration provides no benefit. Genetic drift A storm blows some cranes off-course during their migration so they settle with a new group of cranes. Gene flow Female cardinals choose mates based on how bright and red their breast coloration is. Non-random mating A DNA change causes a change in the shape of red blood cells. Mutation Some frogs produce a skin toxin that makes predators sick after consuming them. These frogs tend to live longer and produce more offspring than those frogs without the toxin. Natural selection Which of these is an example of a population? Squirrels and chipmunks in Frederick, MD Rat snakes in the United States Pine trees in North America Bald eagles in Washington DC Click the blanks to complete the passage below. Organisms that produce more viable offspring are considered to have greater fitnessthan other organisms. The traits of these organisms will generally increase in the population. This phenomenon is referred to as natural selection.Genetic drifttends to affect smallpopulations much more than large populations. This is one reason that once a population gets below a certain size, it is much more vulnerable to extinction.Gene flowtends to increasedifferences between populations. Humans have been experiencing this over the last few centuries as our ability to travel around the world has increased dramatically.A natural event or disaster wipes out most of the population decreasing the gene pool in the bottleneck effect .