Lecture 2: Counter Intuitive Behaviour

Question 1

why do humans eat so many sweets and drink so many soft drinks?

Answer 1

Especially the we know its rots teeth, make you obese, leads to diabetes and is COSTLY

Question 2

Infanticide in Hanuman langurs group / individual selection? And what occurs?

Answer 2

INDIVIDUAL

• -live in social groups, 1 M and group of F.
• • when a M is displaced they new males kills the old ones young (risk being attacked by females)
• SO infanticide free F become pregnant sooner. The male becomes father sooner and has more offspring before being displaced himself

Question 3

group selection is the idea that

Answer 3

certain characteristics of individuals are adaptive not at the individual level but at the group level

• individual will be doing something good for the group but bad for themselves
• e.g. reproducing less to avoid overexploiting resources

Question 4

what is the problem with group selection

Answer 4

individual selection will usually be stronger. Groups with the characteristics necessary for group selection are rare

Question 5

when are “non-restraining” (selfish) type advantageous? Competition WITHIN groups for space or resources/competition BETWEEN groups for space or resources

Answer 5

Competition WITHIN groups for space –> individuals do better

Question 6

when are “restraining” altruistic type advantageous? Competition WITHIN groups for space or resources/competition BETWEEN groups for space or resources

Answer 6

competition BETWEEN groups for space or resources –> groups do better

Question 7

Alcock discusses infanticide in other species:

Answer 7

including lions, giants waterbeds and jacanas

Question 8

infanticide in meerkats

Answer 8

• meerkats live in social groups, with a dominant female & subordinates
• pregnant females will kill the pups of other females, so their young do not have to compete for resources –> direct benefit

Question 9

self sacrifice in Worker Honey bees

Answer 9

• self sacrifice –> casting off part of body
• barbed sting, easy to go in, hard to come out
• alarm pheromone guides other worker bees to the intruder -> releases highly defensive behaviour
• individual gains benefits as pass on genes by helping fam survive, by leaving sting in the victim works for longer

Question 10

worker honey bees sting contains

Answer 10

muscles, nerve ganglion a venom sac and an alarm pheromone gland

Question 11

alarm pheromone main chemical

Answer 11

-very volatile and smell of bananas, isoamy acetate

Question 12

Sex change in Anthias fish

Answer 12

• Female –> Male

- gains fitness as a large male has greater reproductive potential as female eggs are limited

Question 13

Garden spider: waiting for females to mature

Answer 13

• M smaller than F
• M waits near nest and then waits for female to mature, then plucks nest (differently to how prey would) to gain F attention

Question 14

Crabs spider:

Answer 14

Grabs F legs waits till F stop wriggling ties her in silk, copulates and then leaves her to untangle herself

Question 15

nuptial gift

Answer 15

food gift –> persuade female

Question 16

black widow to types

Answer 16

black widow and redneck spider

Question 17

redback spider: differences in F & M

Answer 17

• Female much larger
• F live longer
• M matures at a younger age
• Many males per female
• multiple mating by females occurs

Question 18

redback copulation

Answer 18

ends in cannibalism of male

-male actually gives himself to feel, almost as a nuptial gift

Question 19

Why do redbacks M give themselves to the F to be cannibalised??

Answer 19

Female is less likely to mate again if she has cannibalised the first male