sex

Question 1

two-fold cost of sex ? (john maynard smith)

Answer 1

asexual - all same sex (females)

sexual - half will be male, need male to reproduce (only producing half of the reproductive generation)

Question 2

Muller’s ratchet

Answer 2

sexual species are more bc of muller’s ratchet

a ratchet can only turn in one direction

therefore over time, asexual populations with produce generations with bad mutations (genetic load, burden)

sexual can purge these alleles and reduce genetic load

Question 3

Red queen effect

Answer 3

pops are continually evolving new adaptations in response to evolutionary changes in other organisms to avoid extinction

Question 4

Darwin’s 5 dilemma’s

Answer 4

differential parental investment

puzzling patterns (sexual dimorphism)

types of sexual selection (intra - competition, inter - mate choice)

why be choosy?

roles reversed when factors reversed?

Question 5

Anisogamy

Answer 5

Anisogamy, a form of sexual reproduction, involves the production of gametes of different sizes or shapes, typically a larger, nutrient-rich egg and smaller, more numerous sperm, evolving to maximize reproductive success and promote genetic variation in offspring.

Question 6

parental investment / parental care (uncertain vs certain paternity)

Answer 6

females have to gestate the egg

limitations - females have fecundity (# of eggs are their limit) and males have number of mates (how many hoes they can get)

female have certain paternity, males have uncertain paternity (they might just be investing in kids that aren’t theirs)

Question 7

operational sex ratio

Answer 7

operational sex ratio - ratio of males to females capable of reproducing at a given time (slower rate by females leads to male biased OSR)

Question 8

fundamental asymmetry of sex

Answer 8

alleles that increase male attractiveness should increase in the pop

Question 9

intrasexual vs intersexual selection

Answer 9

intrasexual selection - competition (within, males with other males)

intersexual selection - mate choice, attractiveness (between, males and females competing with each other)

Question 10

ornaments vs arnaments

Answer 10

ornaments - attractive traits that increase mating success

armaments - weaponry to outcompete individuals

Question 11

sexual dimorphisms

Answer 11

sexes look different to boost ‘attractiveness aspect’

Question 12

indirect vs direct benefits

Answer 12

direct benefits include food, protection, nesting sites, all benefit the female directly

indirect benefits are the benefits which affect the quality of her offspring → fisherian runaway

Question 13

what does variance in ‘showiness’ mean

Answer 13

variance in reproductive success determines who is gonna be more choosy (higher variance in males = females are more choosy)

Question 14

good genes theory

Answer 14

females want the ‘good genes’

• long tails are harder to maintain, honest indicator of male quality (only best males can have and maintain a long tail)

weapons - trade offs and energy

• resource allocation - can only choose one trait and have to be allocated specifically

Question 15

mating types (monogamy and its 2 types, polygamy and its 2 types)

Answer 15

monogamy (one male pairs with one female)

• sexual - mate for life
• social - pair but may cheat

polygamy (multiple partners)

• polygyny - males mate with many females
• polyandry - females mate with many males

Question 16

sexual conflict (cyclic)

Answer 16

traits conferring fitness benefit to one sex but a cost to the other

eg. sexual conflict on genital morphology (as phallus in bird specie becomes more elaborate so does females)

antagonistic coevolution of traits (Antagonistic coevolution describes the perpetual “arms race” of adaptation and counter-adaptation between species, such as predators and prey, where the traits of each species exert selective pressures on the other, driving ongoing evolution)