Concept explainers
Videos
_________is the original source of new alleles.
| a. Mutation | c. Gene flow |
| b. Natural selection | d. Genetic drift |
Introduction:
Genes control the phenotypic expression of an organism. For a single character, different organisms can show different variations for a single character. These variations arise due to different alleles for a single gene. Alleles are different forms of a single gene. During sexual reproduction, offsprings get alleles for a gene both the parents
Answer to Problem 1SA
Correct answer:
Mutation is the original source of new alleles. Hence, the correct answer is option a.
Explanation of Solution
Reason for correct answer:
Option a. is given as “Mutation”.
Mutations cause a change in the amino acid sequence of a gene. These changes result in new phenotypic expressions of that gene in the organism. Mutations cause the formation of alleles that cause various phenotypic expressions of the same character in the mutated organism. Therefore, it can be said that the source of new alleles are mutations in the genes of organisms.
Reason for incorrect answer:
Option b. is given as, “Natural selection”.
Natural selection occurs due to the accumulation of variations over generations. These traits are inherited and are different due to crossing over during reproduction. New alleles are not formed by this process. Hence, option b. is incorrect.
Option c. is given as, “Gene flow”.
Gene flow refers to the process by which new genes enter a population or some genes exit a population. There is no creation of new alleles. Hence, option c. is incorrect.
Option d. is given as, “Genetic drift”.
Genetic drift allows the change of allele frequency in a population. Inherited traits accumulate over generations leading to the gradual drift of population. The changes are random events and there is no formation of new alleles. Hence, option d. is incorrect.
Hence, the options b., c., and d. are incorrect.
The original source of new alleles is a mutation. Thus, the correct option is a.
Want to see more full solutions like this?
Chapter 17 Solutions
BIOLOGY:CONCEPTS+APPL.(LOOSELEAF)
- 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_forwardWhich term indicates that a single gene has two or more alleles present in a population? A. Point mutation B. Genotype C. Polymorphism D. Pleiotropyarrow_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_forward
- Genetic drift can be defined as Group of answer choices A. accidental changes in DNA structure b.how lazy loci evolve c. random change in allele frequency over time D. differences in fitness between allelesarrow_forwardAccording to the video “The Biology of Skin Color”, why is it that the allele coding for darker skin did not evolve to protect us from skin cancer? A. Because skin cancer isn't harmful B. Darker skin did develop to protect us from skin cancer C. Because skin cancer usually develops after an individual's reproductive years, so it doesn't affect the ability for someone to pass on their genes D. Because skin cancer usually develops before an individual's reproductive years, so it doesn't affect the ability for someone to pass on their genesarrow_forwardInbreeding is sexual reproduction between individuals that are a. homozygous. b. heterozygous. c. part of the same genetic lineage. d. both a and c.arrow_forward
- John wants a dog with short hair. To do this, he breeds two dogs, both with short hair. This is called A. Natural Selection B. Artificial Selection C. Genetic Modification D. Random Chancearrow_forwardWhich statement illustrates the connection between natural selection and overreproduction of a population? a) populations vary in their inherited traits. b) species produce more offspring than can survive in the environment. c) individuals with inherited traits that promote survival tend to have more surviving offspring. d) individuals with traits that do not enhance survival cannot reproduce.arrow_forwardIn genetics, F stands for filial, which means ________. a. friendly c. final b. offspring d. hairlikearrow_forward
- Why are humans so genetically similar within our species? A. Because humans evolved in multiple locations around the world at different times. B. Because humans evolved in one location (Africa) and we have existed as a species for very long time. C. Because humans evolved in one location (Africa) and we haven't existed as a species for very long. D. Humans are not very genetically similar to one another.arrow_forwardDarwin’s First Clues included _______. a. he saw two different species of flightless bird living in different parts of South America when he would have predicted only one b. armadillos taste like duck c. moths in dark forests become darker over time d. Alleles for sickle cell are more common where stored grains can go badarrow_forwardBritain’s Queen Victoria was a carrier for the allele that causes hemophilia and she passed this allele on to some of her descendants. However, there is absolutely no evidence of anyone in Queen Victoria’s ancestry having hemophilia. A-gene flow B-genetic drift C-mutation D-natural selectionarrow_forward
Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College