Mechanisms of Evolution

Understand evolution: natural selection, genetic drift, gene flow, and mutation in action!

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 them in the passage below. Organisms that produce more viable offspring are considered to have greater fitness than other organisms. The traits of these organisms will generally increase in the population. This phenomenon is referred to as natural selection.Genetic drift tends to affect small populations 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 flow tends to reduce differences between populations. Humans have been experiencing this over the last few centuries as our ability to travel around the world has increased dramatically.