Evolution Study Guide

What will happen to a favorable trait in a population? frequency of alleles for the trait increase in the population so the trait appears more frequently

How does competition affect natural selection? organisms whose adaptations offer an advantage outcompete others for limited food or space and drive natural selection

How does variation affect natural selection? variations in organisms, some having advantageous adaptations, are needed for natural selection to occur

How does overproduction affect natural selection? more organisms than can survive must be produced; a driving force of natural selection

What would cause similar animals to have different adaptations? different environmental conditions require suitable adaptations, which can cause similar animals to have differing adaptations

What is a species? a group of organisms that interbreed and produce fertile offspring

How are some insects resistant to pesticides and others are not? genetic mutations give some members of the population pesticide resistance; variations must exist within the species as part of natural selection

What will happen if a small population of A species becomes isolated from the larger population due to migration? What is this called? allele frequencies will most likely differ between populations; this is a type of genetic drift called the founder effect

What is fitness? the ability of an organism to survive and reproduce

What is an adaptation? a physical or behavioral trait that helps an organism survive in its environment

What is adaptive radiation? a single species or small group of species evolves over a relatively short period of time into several different species that live in different ways; ex. Galapagos finches

What does it mean if two animals have similar DNA sequences? they are closely related

What does the picture below have to do with evolution What does the picture below have to do with evolution? What are these structures examples of? They show evolution from a common ancestor; they are homologous structures that have similar structure but different functions

What can you conclude about fossils in the picture below? deeper fossils are species that existed before the ones closer to the surface

How can similar organisms in similar environments be found on different continents? Geographic isolation and selection pressures cause organisms to possess similar adaptations to similar environments

How are genes and evolution related? A key feature of evolutionary theory is the universal genetic code explaining common ancestry; changes in allele frequencies occur through evolutionary processes such as natural selection

What is the relationship between an isolated population and genetics? The Amish are an example of an isolated population; they have a small gene pool due to the founder effect; this leads to the potential for increased frequency of harmful alleles

Is it good or bad to have A small gene pool? Why? bad- increased frequency of bad alleles

What does an animal laying so many eggs or producing so many offspring have to do with natural selection? Overproduction leads to competition; part of the struggle for existence

What is convergent evolution? Give an example. Different species evolving similar structures to survive in similar environments; ex. birds and bats

What is speciation? What must happen in order for speciation to occur? when a species evolves to become 2 or more species; reproductive isolation must occur

What is genetic drift? Give an example. change in allele frequency due to chance events; founder effect and bottleneck effect

What is the difference between being geographically isolated and reproductively isolated? Reproductive isolation is the ultimate result of geographic isolation, one of the ways new species arise

What are analogous structures? Give an example. Different structures that have similar function ex. Wing of bee and wing of bat

What are vestigial structures? Give an example. Structures that have lost their function over time; pelvic bone in snakes

What do fossils have to do with evolution? evidence for evolution; intermediate fossils link past to present species

What is the difference between ordinary extinction and mass extinction What is the difference between ordinary extinction and mass extinction? Give an example of each. Ordinary extinction is slow but steady death of an entire species Ex. A plant going extinct from overconsumption by a consumer; In mass extinction, many species become extinct all at the same time because of a natural disaster; Ex. A wild fire, flood, or volcano destroys all organisms.

What is a mutation? How can a mutation affect future generations? A change in a DNA sequence; favorable mutation alleles will increase over time and unfavorable mutation alleles will decrease

What are three sources of genetic variation in a population? gene shuffling, mutations, and lateral gene transfer

What must happen to allele frequencies in a population if evolution is occurring? they must change; genetic equilibrium is not evolution

How can Darwin’s ideas about evolution help explain the similar appearance in different vertebrate groups that are not closely related? Darwin proposed that over time, natural selection made a population more fit for its environment. The organisms would look similar because they live in similar environments.

Remember: in order for speciation to occur, reproductive isolation must occur. Organisms that are geographically isolated will eventually become reproductively isolated and then become a new species. Temporal isolation-> isolation that happens because of different mating seasons Be sure to know the differences between artificial selection & natural selection.