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Stearns & Hoekstra: Evolution 2e

Chapter 08

Instructions

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Question 01

What is the main evolutionary relevant difference between sexual and asexual reproduction?

a) Asexual organisms are mainly haploid, while sexual organisms are mainly diploid.

b) Asexual reproduction is faster than sexual reproduction.

c) Asexual reproduction produces offspring identical to the parent, while sexual reproduction generally produces genetically diverse offspring.

d) Asexual reproduction is a "logical" reproduction process, while sexual reproduction is "illogical" as a reproduction process.

Question 02

What is the difference between a diplontic and a haplontic life cycle?

a) Sexual organisms have a diplontic life cycle, asexual organisms a haplontic life cycle.

b) The various life cycle stages are haploid in a haplontic life cycle and diploid in a diplontic life cycle.

c) In a haplontic life cycle, the zygote undergoes meiosis to produce haploid individuals, in a diplontic life cycle meiosis occurs in the diploid adult individuals.

Question 03

Why is bacterial conjugation often described as a form of sex, although it differs in many respects from eukaryotic sex?

a) Because conjugation in bacteria generally results in genetic recombination, just as during meiosis in eukaryotes.

b) Because bacterial conjugation involves the coming together of two individuals, like in eukaryotic sex.

c) Because bacterial conjugation is a special form of reproduction, just as eukaryotic sex.

d) Because eukrayotic sex has probably evolved from bacterial conjugation.

Question 04

Organisms that can reproduce both sexually and asexually are rare. True or false?

a) True

b) False

Question 05

What is the ecological distribution pattern of sexual reproduction?

a) Sexual species predominate in extreme environments and disturbed habitats.

b) Asexual species predominate in extreme environments and disturbed habitats.

Question 06

What does "anisogamy" mean?

a) Males and females are clearly different in morphology and behavior.

b) Male and female gametes are clearly different in size.

c) The numbers of males and females in a population are clearly unequal.

Question 07

Anisogamy is a required for the operation of sexual selection. True or false?

a) True

b) False

Question 08

Which of the following statements about the evolutionary maintenance of sex is correct?

a) The evolutionary maintenance of sexual reproduction is easy to understand: sex generates genetic variation by recombination, which is needed for adaptive evolution, while asexual reproduction does not generate variability.

b) The evolutionary maintenance of sexual reproduction is not easy to understand, because it is not clear that the advantages of sex outweigh the disadvantages.

Question 09

What does the two-fold disadvantage of sex refer to?

a) The fact that sex requires two parents, in contrast to a single parent in asexual reproduction.

b) The fact that if males contribute only genes to their offspring, sexual females "waste" on average half their reproductive potential on sons.

Question 10

Sexual recombination can speed up evolution by bringing together beneficial mutations that have arisen in different lines of descent.

a) This advantage of sex is much greater in large than in small populations.

b) This advantage of sex is independent of population size.

Question 11

Muller's Ratchet refers to which of the following mechanisms?

a) In asexual populations the mean number of deleterious mutations per genome will always increase, while in sexual populations it also can decrease.

b) Once the optimal genotype is lost from the population by genetic drift it can be reconstituted by recombination in a sexual population, but not in asexual population.

Question 12

Theory predicts that sex will be advantageous in host-parasite interactions. True or false?

a) True

b) False

Question 13

Do advances in our understanding of the evolution of sex mainly require development of more sophisticated theory, or more experimentation?

a) Theory development

b) Experiments

Question 14

A sexual genetic system is more vulnerable to the spread of "selfish" genes, than an asexual system. True or false?

a) True

b) False

Question 15

A pluralistic explanation of sex means:

a) that sex has evolved independently a number of times.

b) a combination of different explanations, which do not exclude each other.

 

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