Section Outline Section 16 2 Go to Section

Section Outline Section 16 -2 Go to Section:

Natural Selection on Single-Gene Traits _______ on _____ traits can lead to changes in __________ and thus to ____. In a hypothetical population of lizards, individuals are mostly demonstrate a brown _____, which is ____, so brown lizards are ____ ___ or __, and make up 80% of the population. Go to Section:

Natural Selection on Single-Gene Traits 20% of the lizard population show the black _____, which arose as a result of a non-lethal _______, and are ____ __. According to _____-____, the ________ of the recessive allele q is _____ or _____, so… Go to Section:

Natural Selection on Single-Gene Traits the ________ of the dominant p allele is _____. Because of the black lizards’ darker color, they absorb more heat from the sun, so they warm up faster on cool days, allowing them to move faster to avoid predation. After 30 generations, the black Go to Section:

Natural Selection on Single-Gene Traits _____ makes up ___ of the lizard population, so the frequency of the ____ q allele is now 77. 5%. The change in the frequency of the alleles indicates ____ caused by ________. Go to Section:

Natural Selection on Polygenic Traits In _____, _______ can affect a population in three ways: _____, ________, and ________. Go to Section:

Figure 16– 6 Graph of Directional Selection Section 16 -2 Key Directional Selection Food becomes scarce. Go to Section: Low mortality, high fitness High mortality, low fitness

Figure 16– 7 Graph of Stabilizing Selection Section 16 -2 Stabilizing Selection Key Low mortality, high fitness Percentage of Population High mortality, low fitness Brightness of Feather Color Go to Section: Selection against both extremes keep curve narrow and in same place.

Figure 16– 8 Graph of Disruptive Selection Section 16 -2 Disruptive Selection Low mortality, high fitness High mortality, low fitness Population splits into two subgroups specializing in different seeds. Beak Size Go to Section: Number of Birds in Population Key Number of Birds in Population Largest and smallest seeds become more common. Beak Size

Genetic Drift If you flip a coin, there is a ___ chance of the coin coming up heads. If you flip the coin 100 times, about __ should be heads. If you flip the coin 4 times, you are supposed to get _ heads, but you probably won’t, because the sample size is small. _______ is a change in ________ due to random chance, especially in small populations. Go to Section:

Genetic Drift: Founder Effect Section 16 -2 Sample of Original Population Descendants Founding Population A Founding Population B Go to Section:

Genetic Drift: Founder Effect Section 16 -2 Sample of Original Population Descendants Founding Population A Founding Population B Go to Section:

Genetic Drift: Founder Effect Section 16 -2 Sample of Original Population Descendants Founding Population A Founding Population B Go to Section:

Evolution vs. Genetic Equilibrium The _____-____ principle states that allele frequencies will remain ____ unless one or more factors cause those frequencies to change. If those factors are not present, allele frequencies remain constant, and a __________ exists. Go to Section:

Evolution vs. Genetic Equilibrium Five conditions are required to maintain ________: Go to Section:

Evolution vs. Genetic Equilibrium In order for ______ to occur, all members of the population must have equal opportunity to produce offspring. In natural populations, like ____, or _______, members compete or even fight for the opportunity to mate. Go to Section:

Evolution vs. Genetic Equilibrium For __________ to occur, a population must be large, so _______ doesn’t cause changes in allele frequency by random chance. No migration can occur, since movement in and out of the population changes the ____ of ______. Go to Section:

Evolution vs. Genetic Equilibrium For __________ to occur, there must not be _____, which introduce new ______, and no ________ can take place which gives any one _____ a survival advantage over another. In some populations, these conditions may be met or nearly met over long periods of time, and little or no ____ occurs. Go to Section:

Should the Use of Antibiotics Be Restricted? Read the Issues in Biology article on p. 403 in your text. Then watch the video Why Does Evolution Matter Now? and discuss the question: Should the use of antibiotics be restricted? Go to Section: