13 The ultimate source of all genetic variation is: mutations b. crossing over m

Question

13 The ultimate source of all genetic variation is: mutations b. crossing over meiosis d. polyploidy 14. Without extensive medical intervention (high-tech equipment in modern hospitals it is unusual for human babies weighing under 3 pounds or over 13 pounds to be born alive and survive (along with their mothers). This is an example of? a. natural selection b. survival of the fittest c. genetic drift d gene flow e geographic variation 15 Which of the following is most likely to improve the fitness of a population to its environment? a. genetic drift b. mutation natural selection gene flow e none of the above will improve fitness 16. Which of the following was NOT included in Darwin's theory of Natural Selection? a. Mendelian genetics b. potential for overproduction of offspring c. variability among individuals of a species d. survival of the fittest e relatively constant numbers of individuals 17. One of the major sources of evidence for evolution is in the comparative anatomy of organisms. Features that look different but have similar structural origin are called homologous structures. b. analogous structures. c. vestigial structures. d. equivalent structures 18. All of the following are sources of genetic variation related to sexual reproduction, EXCEPT: a. crossing-over b. production of offspring by two parents c. independent assortment of homologous chromosomes mutation e. random fertilization.

Explanation / Answer

13. Mutation is the ultimate source of the genetic variation because it creates changes in the DNA which leads to formation of new allele. Sometime one mutation is sufficient to change the allele function but sometime accumulation of several mutation leads to changes. Correct answer is a.

14. It is due to natural selection lead to changes in the human pelvis. Correct answer is a.

15. Natural selection of sexual selection is key to survive some traits and reproduce them. Correct answer is c.

16. Mandelian genetics was not included in the darwin’s theory of evolution. Answer is a.

17. Homologous structures may look different but they originate from common ancestor. Answer is a.

18. Random fertilization is not considered for source of variation. Answer is e.

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