Campbell Biology: Concepts.. (Custom Package)
8th Edition
ISBN: 9781323042649
Author: Central Texas
Publisher: PEARSON
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Chapter 13, Problem 6TYK
If an allele is recessive and lethal in homozygotes before they reproduce,
a. the allele will be removed from the population by natural selection in approximately 1,000 years.
b. the allele will likely remain in the population at a low frequency because it cannot be selected against in heterozygotes.
c. the fitness of the homozygous recessive genotype is 0.
d. both b and c are correct.
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Which of the following conclusions are MOST likely to be supported by genetic evidence? A. Some modern-day organisms did not exist in the past. B. Some organisms found in the fossil record do not currently exist. C. Environmental change affected the fitness of individuals differently based on their traits. D. Some disease-causing traits may remain in a population because their alleles provide an advantage to heterozygotes.
Biologists sometimes say that “natural selection depends on the specific environment where a species lives.” What does this statement mean?
A)
A) If populations of a species are in different environments, traits that individuals need to meet their needs in each environment will appear.
B) Traits can be helpful or harmful. If populations of a species are in different environments, some traits that are helpful in one environment might be harmful in another environment.
C) Traits are always either helpful or harmful, and the environment of a population doesn’t matter. If populations of a species are in different environments, the same traits will always be helpful.
D) Species were formed to perfectly match their environment. The traits of individuals in a species depend on the specific environment in which they were created.
When we take, say, 100 individuals of a species of beetle from the wild and place them in a new environment that is not so different that they are unable to thrive but different enough so that they are experiencing a new selective regime, say, a lower temperature, what typically happens?
A - Sexual selection causes some larvae to be able to survive in the cooler temperatures and other individuals to be unable to survive because they need warmer temperatures.
B - We are unable to measure phenotypic selection, presumably because we do not have much variation among individuals for how they handle temperature.
C - The founder event assures us that the new population will be strictly representative of the source population (especially if we took all the 100 from the same location rather that from throughout the range of the species).
D - The population evolves to be tolerant of the lower temperature; it can do this because of latent variation already in the 100 founding individuals.
E -…
Chapter 13 Solutions
Campbell Biology: Concepts.. (Custom Package)
Ch. 13 - Summarize the key points of Darwins theory of...Ch. 13 - Complete this concept map describing potential...Ch. 13 - Which of the following did not influence Darwin as...Ch. 13 - Natural selection is sometimes described as...Ch. 13 - In an area of erratic rainfall, a biologist found...Ch. 13 - If an allele is recessive and lethal in...Ch. 13 - In a population with two alleles, B and b, the...Ch. 13 - Within a few weeks of treatment with the drug 3TC,...Ch. 13 - Prob. 9TYKCh. 13 - Write a paragraph briefly describing the kinds of...
Ch. 13 - In the early 1800s, French naturalist Jean...Ch. 13 - Sickle-cell disease is caused by a recessive...Ch. 13 - It seems logical that natural selection would work...Ch. 13 - SCIENTIFIC THINKING Cetaceans are fully aquatic...Ch. 13 - A population of snails is preyed on by birds that...Ch. 13 - Advocates of scientific creationism and...
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- Population genetics is the study of ________. a. how allele frequencies in a population change over time b. populations of cells in an individual c. the rate of population growth d. how genes affect embryological developmentarrow_forwardIn which of the following pairs do both evolutionary processes introduce new genetic variation into a population? a. natural selection and genetic drift b. mutation and gene flow c. natural selection and gene flow d. gene flow and genetic driftarrow_forwardGalapagos medium ground finches are found on Santa Cruz and San Cristóbal islands, which are separated by about 100 km of ocean. Occasionally, individuals from either island fly to the other island to stay. This can alter the allele frequencies of the population through which of the following mechanisms? a. natural selection b. genetic drift c. gene flow d. mutationarrow_forward
- How Can We Measure Allele Frequencies in Populations? Explain the connection between changes in population allele frequencies and evolution, and relate this to the observations made by Wallace and Darwin concerning natural selection.arrow_forwardYou are studying a species of beetle known as a Flumbodoodle Beetle. The beetle has long spikes on its shell to defend itself from potential predators. You are interested in studying evolution in this beetle. Which of the following studies do you not need to conduct to determine if the long spike trait can evolve by natural selection. a. A study that determines whether beetles with longer spikes survive and reproduce better than beetles with shorter spikes. b. A study that measures the spike length variation across multiple individuals in a population. c. A study where you measure the spike length on the parents and a study where you measure the spike length on the offspring. d. A study that determines whether these spikes on the beetle are also used in mate choice contexts.arrow_forwardWhich statement best summarizes why genetic drift tends to impact small populations more than large populations? A. Small populations have a heterozygote advantage because heterozygotes are more common than homozygotes. B. Small populations have a smaller gene pool, so random changes influence them more. C. Small populations have a relatively large gene pool, so the founder effect stabilizes their alleles.D. Small populations tend to experience directional selection, making one phenotype more common.arrow_forward
- Allele frequency refers to the fraction of individuals with a particular version of a given gene.What effect does natural selection have on the allele frequency of a population? A. It causes the allele frequency to resemble that of a small number of individuals that became separated from the rest of the population. B. It causes random changes and the allele frequency of certain traits may increase or decrease. C. It increases the frequency of alleles that improve a species' survival in a particular environment. D. It greatly reduces the total population, which increases the effects of genetic drift on allele frequency.arrow_forwardDarwin based his Theory of Evolution by Natural Selection on series of observations. Which of the following is not associated with his theory? a) individuals in a population vary phenotypically b) organisms tend to under-reproduce themselves c) there are limited resources for which individuals compete d) some variations possessed by individuals of a population are inheritedarrow_forwardWhat affect will inbreeding tend to have on genotypic frequencies in a population? a) It will increase the frequency of genotypes that produce a dominant phenotype. b) It will decrease the frequency of genotypes that produce a dominant phenotype. c) It will increase the frequency of homozygous genotypes. d) It will increase the frequency of heterozygous genotypes.arrow_forward
- With stronger natural selection, was the more beneficial allele lost from these small populations?a) It was lost very frequently, and the strength of natural selection did not make any difference.b) It was never lost.c) It was lost a few times, but not very often, and it was lost less frequently under strong selection.d) It was lost a few times, and it was lost more frequently under strong selection.arrow_forwardWhich evolutionary forces a. cause an increase in genetic variation both within and between populations? b. cause a decrease in genetic variation both within and between populations? c. cause an increase in genetic variation within populations but cause a decrease in genetic variation between populations?arrow_forwardThis model shows the process of natural selection on rabbits demonstrating variation in fur color over several generations. Using the model, what most likely led to the loss of white furred rabbits in the population? A) the white rabbits did not reproduce fast enough to survive B) white was a recessive trait and therefore not passed on to any offspring C) the white fur was a favorable trait but was never prevalent in the population D) the rabbits with white fur had less camouflage in the environment and were more easily preyed on by predatorsarrow_forward
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