chapter 11- sex: causes and consequences

Question 1

reproduction:

Answer 1

generation of new individuals from existing ones; fundamental characteristic of life

Question 2

asexual reproduction:

Answer 2

creation of offspring from single individual, results in genetic clones

Question 3

sexual reproduction:

Answer 3

creation of offspring through fertilization of gametes; results in genetic combination of parents

Question 4

is it possible for a species to reproduce both sexually and asexually?

Answer 4

yes

Question 5

sex is a paradox assuming what two things?

Answer 5

1. asexual and sexual females produce the same numbers of offspring
2. offspring on sexual and asexual females have the same fitness

Question 6

what are some other costs of sex?

Answer 6

genetic recombination (loss of alleles)
mate searching (time, energy, predation)
mating (injury and death)
sexually-transmitted diseases (parasites and pathogens)

Question 7

what are the benefits of sexual reproduction?

Answer 7

increased genetic variation (novelty)
- beneficial mutations can be combines and deleterious mutations can be removed (avoiding muller’s ratchet)

Question 8

what is the red queen effect?

Answer 8

when sexual repro leads to increased resistance to parasites and pathogens

Question 9

what was the example of the red queen effect with the new zealand freshwater snail?

Answer 9

different areas of new zealand had populations where some snails reproduced sexually more often and other areas where asexual repro was more common

Question 10

why ate there two sexes?

Answer 10

selection can act on gamete reproduction

Question 11

which strategies can be favored when looking at the reason for having two sexes?

Answer 11

• maximize fertilization rate
• maximize development, growth, and survival

Question 12

anisogamy

Answer 12

asymmetrical gamete investment
females have fewer and larger gametes, while men have more smaller gametes

Question 13

what’s an example of an extreme regarding anisogamy?

Answer 13

the kiwi bird carries the largest egg of any bird relative to its body size.

Question 14

parental investment

Answer 14

resources devoted to current offspring that cannot be devoted to future offspring; ranges from gamete production to parental care
usually higher in females than males

Question 15

operational sex ratio

Answer 15

ratio of sexually receptive males to females at any given time within a population

Question 16

what is operational sex ratio influenced by?

Answer 16

sex ratio at birth, age of sexual maturity, lifespan, gestation time, parental care, and mating system

Question 17

sexual selection

Answer 17

natural selection for mating success
(differences in reproductive success resulting from competing mates)

Question 18

what does sexual selection lead to?

Answer 18

evolution of sexual dimorphism

Question 19

what does INTRAsexual selection lead to?

Answer 19

arnaments
(antlers, horns)

Question 20

what does INTERsexual selection lead to?

Answer 20

ornaments
(peacock feathers)

Question 21

how can the direction and strength of sexual selection be predicted ?

Answer 21

the sex with the greatest variance in reproductive success experiences stronger sexual selection

Question 22

does high variance in reproductive success lead to intense or mild sexual selection?

Answer 22

intense selection

Question 23

why do mating systems evolve?

Answer 23

because of the benefits and costs they confer on males and females

Question 24

monogamy

Answer 24

one male pairs with one female

Question 25

sexual/ genetic monogamy

Answer 25

partners mate with each other exclusively

Question 26

social monogamy

Answer 26

partners pair but may cheat

Question 27

serial monogamy

Answer 27

sexual or genetic monogamy for one breeding bout

Question 28

polygyny

Answer 28

males mate with multiple females

Question 29

polyandry

Answer 29

females mate with multiple males (very rare)

Question 30

promiscuity

Answer 30

males and females mate multiply

Question 31

the sex with the greatest variance in reproductive success experiences leads to what?

Answer 31

stronger sexual selection greater opportunity for selection

Question 32

do males compete for females directly or indirectly?

Answer 32

it can be both

Question 33

example of how males compete both directly and indirectly compete for females

Answer 33

harlequin beetle fights for territories, pseudoscorpions fight for females on the harlequin beetles back.

Question 34

example of how males compete for paternity

Answer 34

dragonflies have a spoon like penis that scoops out the sperm from previous males.

Question 35

howe might a male get a females attention?

Answer 35

bring gifts, display elaborate ornaments, do elaborate courtship rituals

Question 36

direct benefits that a women could receive from choosing a good mate

Answer 36

benefit the female directly - food, nest sites, protection

Question 37

indirect benefits ?

Answer 37

benefits that affect the genetic quality of the females off spring - "good genes" "fishers runaway" -male traits advantageous because they're attractive (bright coloring).

Question 38

what is an example of a nuptial gift?

Answer 38

spermatophores in katydids

Question 39

example of a direct benefit in praying mantis and redback spider

Answer 39

female kills praying mantis and redback spiders after mating with them

Question 40

other forms of direct benefits, more common in humans

Answer 40

protection rom harassment access to high quality territories reduced risk of parasites/ diseases help raises young

Question 41

how do some ornaments act as handicaps ?

Answer 41

females widow birds believe that tail length is an honest indicator of strength and good genes because males need to be strong and have enough food to carry around a large tail.

Question 42

what is fishers runaway selection

Answer 42

preference and traits are genetically correlated - male color and female preferences in sticklebacks and blue/ red footed boobies

Question 43

what is something that female preferences may arise from?

Answer 43

preexisting sensory bias ex. preferences for orange color because food the women like is orange

Question 44

explain how prolonged courtship by males after mating leads to fertilization

Answer 44

females can mate with multiply males, but chooses which sperm she wants to use depending on the tapping sequence the males give to her back after mating

Question 45

sexual conflict

Answer 45

traits that confer a fitness benefit on one sex but cost to the other traits coevolve antagonistically female ducks have a cork screw like tract to avoid being mated with

Question 46

genetic bias of a trait involve in sexual conflict

Answer 46

how genes regulates antennae phenotype in water striders