Chapter 21

Question 1

Asexual Reproduction

Answer 1

Offspring is a clone of parents (genetically identical); differences are from mutations; low variation

Question 2

Most Common Way of Asexual Reproduction

Answer 2

Parthenogenesis; suppress meiosis

Question 3

Two fold cost of sex

Answer 3

Sexual reproduction; lose half of females and asexual reproduction; all are females

Question 4

Give three costs of sex

Answer 4

Hard to find a mate, nurture small amount of offspring, compromise through fitness, pregnancy can be dangerous

Question 5

What is the long term positive of being sexual?

Answer 5

Increasing the variance in fitness through recombination, good in fluctuating environment, favored due to selective pressures, muller’s ratchet

Question 6

Muller’s Ratchet

Answer 6

Hypothesis that explains that sex is maintained because asexual population would accumulate slowly until the fitness was so low that the population will become extinct; assumes all mutations are bad; more individuals with many bad mutations

Question 7

Why is sex good in a fluctuating environment?

Answer 7

Allows populations to adapt to environment, recombination happens quickly for sexual beings

Question 8

Red Queen Hypothesis

Answer 8

Arms race between host and parasite/pathogen; sexual reproduction provides new combinations giving the host new advantage

Question 9

Why do mutations happen immediately with sexual reproduction?

Answer 9

No problem of clonal interference