lecture 13 - evolution of sex

Question 1

why sexual reproduction is less effective

Answer 1

only 1/2 of genes are present in offspring
only 1/2 of population are producing offspring directly

Question 2

costs of sexual reproduction

Answer 2

finding and courting a mate
courtship- time, energy and is dangerous
courtship is showy and exposes you to predators
allowing mate close to you exposes you to disease, parasites and physical injury

Question 3

advantages of sexual reproduction

Answer 3

reduces sib-competition
better protection against parasites

Question 4

why is variation in offspring good

Answer 4

good bet when future is uncertain- some animals produce both ways in different seasons aphids

Question 5

is variation always good

Answer 5

asexual offspring do well in stable environment
sexual offspring do better in changing environment

Question 6

sib-competition model

Answer 6

increased variation= reduced competition
can survive in many different habitats

Question 7

better protection against parasites

Answer 7

variation means parasite is less adapted to offspring

Question 8

individual advantages to sexual reproduction

Answer 8

sib-competition
parasite protection
mullers rachet
hill-Robertson effect

Question 9

mullers rachet

Answer 9

prevents us from going back to asexual reproduction
bad allele is not always passed down to child

Question 10

hill- Robertson effect

Answer 10

getting multiple mutations into 1 individual is easier in sexuals

Question 11

what are examples of features males use to attract mates

Answer 11

colours, dances, building structures, feathers, plumes

Question 12

what do the male’s showy features demonstrate to females

Answer 12

honest signalling - signals poor quality males can’t maintain

Question 13

2 theories to explain extreme males

Answer 13

fishers runaway train
zahavis handicap principle

Question 14

fishers runaway train

Answer 14

selection drives to a large extreme

Question 15

zahavis handicap principle

Answer 15

handicap shows how strong they are

Question 16

what did Marie Petries’ experiment in peacocks show

Answer 16

females choose males with longer tails
longer-tailed males survive longer
offspring from long-tailed males grew faster and survived longer
handicap in undeniable feature of strong genes

Question 17

what does these showy features show about evolution

Answer 17

evolution doesn’t produce what is best for the species