cycle 7

Question 1

sex

Answer 1

exchange of genetic material; mixing of genetic variation through sex to produce new genotypes and phenotypes

Question 2

sex in sexually reproducing organisms

Answer 2

gametes fuse to generate new combinations of alleles in offspring

Question 3

sex in asexually reproducing organisms

Answer 3

acquire DNA from another organism or their environment

Question 4

dioecious

Answer 4

individuals of separate sexes mating

Question 5

monoecious

Answer 5

individuals are both sexes in sexual reproduction- hermaphrodites (most plants are monoecious, have reproductive tissue of both sexes)

Question 6

simultaneous hermaphrodites

Answer 6

simultaneously male and female (e.g. earthworms)

Question 7

sequential hermaphrodiates

Answer 7

starts as one sex and develops into another (e.g. bluehead wrasse, starts as a female and develops into a male if the dominant male dies, clownfish do the opposite)

Question 8

protogyny

Answer 8

female -> male

-female has better reproductive success as smaller, male has better as a larger organism

Question 9

protandry

Answer 9

male->female
-males have better reproduce success at a smaller size, females have better reproductive success at a larger time (greater ability to produce more eggs at a bigger size)

Question 10

sex in fungi and ciliates

Answer 10

can have 2 or more mating types, gametes of different mating types fuse, exchange nuclei between mating types

Question 11

obligately sexual

Answer 11

only reproduces through sexual reproduction

Question 12

facultatively sexual

Answer 12

can reproduce sexually or asexually

Question 13

obligately asexual

Answer 13

only reproduces asexually

Question 14

parthenogenesis

Answer 14

type of asexual reproduction in animals, females produce offspring without sex (offspring develop from unfertilized diploid eggs)

• eggs remain diploid during gamete formation (no meiosis, clones)
• OR DNA in haploid egg replicates- goes haploid to diploid (not clones)

Question 15

asexual reproduction in unicellular organisms

Answer 15

divide through binary fission (bacteria, archaea) or by mitosis (unicellular eukaryotes)
-genetically identical offspring

Question 16

sex in bacteria and archaea

Answer 16

bacterial conjugation, transferring plasmids

Question 17

origin and history of sex

Answer 17

• life started with prokaryote LUCA (reproduces asexually but also likely sexually as well)
• after meiosis evolved, most eukaryotes were able to reproduce sexually

Question 18

disadvantages of sex

Answer 18

it is risky (time-consuming, exposure to predation and STDs), costly (only 1/2 of genetic material is inherited- 2 fold cost of sex), and inefficient (producing males reduces reproductive output- only females grow the population)

Question 19

advantages of sex

Answer 19

generates variation not possible through asexual reproduction, leads to new and better combinations of alleles, leads to genetically distinct offspring, generates genotypes of higher fitness more quickly

Question 20

the lottery model

Answer 20

sexual populations have a greater diversity of offspring; increased probability of some offspring surviving/having favourable phenotypes (have variants to survive in a different environment)

Question 21

how does sex make better combinations of alleles?

Answer 21

• brings good alleles together, will have high fitness
• brings bad alleles together, low fitness (removed by selection)
• highest fitness occurs with a combination of beneficial variants

Question 22

clonal interference

Answer 22

beneficial variants of different clones in asexually reproducing organisms cannot be combined together to create offspring with the highest fitness

Question 23

sexual selection

Answer 23

struggle for mates, traits favoured that increase mating success will increase individual fitness, even for exaggerated traits that can reduce survival

Question 24

intersexual selection

Answer 24

one sex chooses (females choose mates based on displays and physical traits- elaborate courtship, ornamentation, males compete for attention)

Question 25

which sex is the chooser in intersexual selection?

Answer 25

the sex that invests more in parental care, the one that has relatively few contributions to the next generation (must be selective to ensure the quality of offspring- usually females)

Question 26

intrasexual selection

Answer 26

individuals of one sex compete amongst themselves - males monopolize access to females (outcompete rivals, direct control of females, control of a resource important to females) - females compete too (territory, access to mates, resources)

Question 27

sperm competition

Answer 27

- swimming speed (fastest sperm to get to the egg) - scrapers (scrape out sperm deposited by other males) - mating plugs (after mating, leave a plug to prevent other males from mating)

Question 28

the mating game

Answer 28

male of the highest fitness is the winner, the male of the lowest fitness is the loser (average fitness is the same throughout)

Question 29

lessons from the mating game

Answer 29

- males (reproduction is limited by access to females, individual fitness can vary, higher potential fitness) - females (limited gametes, must choose mates wisely, individual fitness is often closer to the mean) - average fitness is similar for both sexes

Question 30

direct benefits of being choosy

Answer 30

attractive individuals are good parents; food, territory, and protection for offspring

Question 31

indirect benefits of being choosy

Answer 31

attractive individuals have good alleles, improve survival or attractiveness of offspring (better immunity, sexy sons)

Question 32

sexual dimorphism

Answer 32

genders have a distinct difference in size or appearance, males are often bigger and brighter in colour (the relative role in parental care affects the degree of sexual dimorphism)

Question 33

females provide most of the parental care

Answer 33

makes them unavailable for reproduction, male competition for females is high, males are under stronger sexual selection

Question 34

males provide most of the parental care

Answer 34

availability of males is limited, females are under stronger sexual selection

Question 35

biparental care

Answer 35

males are removed from seeking additional mating opportunities, both sexes compete for mates, sexual selection acts on both sexes (little to no dimorphism)