Dark brown coloration arises Starting population has mostly light wings. by a new mutation that creates a dark allele. Dark brown wings make the butterflies less susceptible to predation. The dark brown butterflies have a higher Darwinian fitness than do the light butterflies. Light wings Dark wings Many generations Population after directional This population has a higher mean fitness than the starting population because the darker butterflies are less susceptible to predation and therefore are more likely to survive and reproduce. selection has mostly dark wings. Light wings Dark wings (a) An example of directional selection (b) Graphlcal representatlon of directional selection Number of individuals Number of individuals

Dark brown coloration arises Starting population has mostly light wings. by a new mutation that creates a dark allele. Dark brown wings make the butterflies less susceptible to predation. The dark brown butterflies have a higher Darwinian fitness than do the light butterflies. Light wings Dark wings Many generations Population after directional This population has a higher mean fitness than the starting population because the darker butterflies are less susceptible to predation and therefore are more likely to survive and reproduce. selection has mostly dark wings. Light wings Dark wings (a) An example of directional selection (b) Graphlcal representatlon of directional selection Number of individuals Number of individuals

Biology: The Unity and Diversity of Life (MindTap Course List)

14th Edition

ISBN:9781305073951

Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Publisher:Cecie Starr, Ralph Taggart, Christine Evers, Lisa Starr

Chapter43: Animal Behavior

Section: Chapter Questions

Problem 2CT

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In a certain population of frogs, 120 are green, 60 arebrownish green, and 20 are brown. The allele forbrown is denoted GB, while that for green is GG, andthese two alleles are incompletely dominant.a. What are the genotype frequencies in thepopulation?b. What are the allele frequencies of GBand GG inthis population?c. What are the expected frequencies of the genotypes if the population is at Hardy-Weinbergequilibrium?
Why is a balancedfrequency of different allelesof a gene in a population moreuseful for the survival of thatpopulation facingenvironmental changes?
Imagine that you are a conservation biologist responsible for the well-being of a bufello herd consistingof 100 mature males and 100 mature females. In this herd, there is no appreciable mutation, there isno migration in or out, and there is no selection. At the Fuzzy gene locus, there are two alleles, G and E.Homozygous G individuals have fuzzy fur, homozygous E individuals have rough fur, and heterozygoteshave shaggy fur. Suppose you survey the herd and find that there are 44 fuzzy individuals, 72 shaggyindividuals, and 84 rough individuals. Suppose you watch the buffalo and discover that while all the females breed, a small number of males(10) establish breeding harems, while the other males do not breed.a) What is the effective population size of this herd? That is, what size "ideal" population ofbalanced sex ratio would have genetics similar to this population?b)How does the effective population size compare to the actual population size?c) Under Hardy-Weinberg equilibrium, what…
Imagine that you are a conservation biologist responsible for the well-being of a bufello herd consistingof 100 mature males and 100 mature females. In this herd, there is no appreciable mutation, there isno migration in or out, and there is no selection. At the Fuzzy gene locus, there are two alleles, G and E.Homozygous G individuals have fuzzy fur, homozygous E individuals have rough fur, and heterozygoteshave shaggy fur. Suppose you survey the herd and find that there are 44 fuzzy individuals, 72 shaggyindividuals, and 84 rough individuals.a)What is the size of the population?b)Do the alleles have a simple dominance relationship? Describe.c)What are the frequencies of the two alleles?d)Is the population in Hardy-Weinberg equilibrium?If not, how do you know, and what might be the cause?
Two populations of snakes are separated by a river. The snakescross the river only on rare occasions. The snakes in the two populationslook very similar to each other, except that the members ofthe population on the eastern bank of the river have a yellow spoton the top of their head, whereas the members of the western populationhave an orange spot on the top of their head. Discuss twoexperimental methods that you might use to determine whether thetwo populations are members of the same species or members ofdifferent ones.
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Ancestors of the beach mouse mayhave exhibited variations in their coat color. Because of the prevalence of visualpredators, the better-camouflaged (lighter) mice in the beach habitat may havesurvived longer and been able to produce more offspring. Over time, a higher andhigher proportion of individuals in the population would have had the adaptation of lighter fur that acted to camouflage the mouse in the beach habitat.
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Pikas are small mammals that live at high elevations on the talus slopesof mountains. Most populations located on mountaintops in Coloradoand Montana in North America are isolated from one another: the pikasdon’t occupy the low-elevation habitats that separate the mountaintopsand don’t venture far from the talus slopes. Thus, there is little gene flowbetween populations. Furthermore, each population is small in size andwas founded by a small number of pikas.A group of population geneticists proposes to study the amount ofgenetic variation in a series of pika populations and to compare theallelic frequencies in different populations. On the basis of the biologyand distribution of pikas, predict what the population geneticists willfind concerning the within- and between-population genetic variation.
One concept of conservation biology is known as minimum viablepopulation. Some species’ populations are so fragmented andsmall that they may have very little genetic variability left. Withminimal genetic variation in the population, there is little likelihoodthat a population can adapt to an environmental threat, such as anew disease. Florida panthers are at or below the minimum viablepopulation level (estimated population less than 80). 1)Do you think that it is practical to use limited resources toconserve a population like the Florida panther? 2)Why?
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