Intragenomic conflict

Question 1

What two hypotheses look to explain why polyandry occurs?

Answer 1

Sexy sperm hypothesis- by mixing the sperm of several males, females ensure that the sperm that prevails is the sperm that is the most competitive and so females sons would also have the most competitive sperm

Meiotic drive hypothesis- heritable differences in sperm competitive ability persist at equilibrium and so females that are multiply mated will have offspring with higher than average viability and remating will reduce exposure to heritable genetic elements

Question 2

What was the aim of the paper by Price et al looking at the effect of selfish genetic elements?

Answer 2

Examined the evolutionary response of remating rate in the presence of the selfish gene SR which is an X-chromosome meiotic driver in fruit fly

Question 3

What are the effects of the SR gene in the fly?

Answer 3

Causes developmental failure of all sperm bearing a Y-chromosome so males with this gene can only bear daughters- leads to female biased populations

Question 4

Who wrote the paper regarding the Tragedy of the commons of Fisheries? What was proposed?

Answer 4

Paper by Guitierrez et al (2010)- examined 130 case studies of fisheries all over the world, and looked to see if co-management strategies were successful in the running of co-management fisheries
Found that if there were more than 8 success factors present, such as social cohesion, economic, and local market factors present, as well as a strong community leader, the fishery was likely to prosper.

Question 5

What did Elinor Ostrom propose regarding the tragedy of the commons?

Answer 5

Ostrom carried out experiments in a variety of situations and found that where communities could establish rules about how resources were shared, resources were often used in economically and ecologically sustainable ways.

Question 6

What four solutions have been proposed for the TOC?

Answer 6

1.) Selfish cooperation 2) Coercion 3) Reputation 4)

Optional participation

Question 7

What is reproductive skew?

Answer 7

The process where animals that exhibit cooperative breeding show some individuals having more of the reproductive output than others- generally due to limitation of resources

Question 8

What are the consequences of reproductive skew?

Answer 8

Eviction, coercion, infanticide, recruitment of bee-eater birds to join the parents nest

Question 9

What three hypotheses propose why cooperative breeding evolved?

Answer 9

1- Ecological restraints hypothesis- states that the lack of resources in an area, such as lack of nesting site and food may lead to cooperative breeding
2- Life History Hypothesis- elders or dominants may have a short turnover rate and due to this, territory is not passed on to the young
3- Benefit of philopatry- emphasises the benefits of staying near the nest

Question 10

What did the study by Young et al, 2005, show in terms of how eviction affected the meerkats in cooperatively breeding groups?

Answer 10

Showed that meerkats respond to eviction by raised glutocorticoid levels (GC) in faecal samples and had down regulation of leutinising hormone and gonadotropin releasing hormone.
Meerkats also lost weight and aborted often while evicted

Question 11

What is the stress-related suppression hypothesis?

Answer 11

States that in cooperatively breeding groups, the continual activation of the HPA axis and GC hormone levels through chronic stress or attacks can lead to subordinates being less fertile

Question 12

What evidence supported the stress-related suppression hypothesis

Answer 12

In response to eviction, more stress was caused, and prevented meerkat subordinates from conceiving. Eviction only seen when the dominant was pregnant and occurred only for individuals older than 9 months

Question 13

What is the restraint model?

Answer 13

Poses that dominants will use the threat of eviction to place a limit on the amount of reproduction which subordinates can engage in

Question 14

What it the compromise model?

Answer 14

Suggests that threats will be ignored and there is a compromise between the optimum of the dominant and that of the subordinate

Question 15

What does the game theory propose about cooperative hunting?

Answer 15

Proposes that group hunting should increase linearly with success. However, the benefit of group hunting on the group is capped at 100% success- group will either succeed in catching the prey or not and increasing past the point where success occurs will yield no benefit

Question 16

What are the main benefits to cooperative hunting?

Answer 16

Group hunting will increase the likelihood that prey will be caught, larger prey or a larger quantity of prey can be caught, less distance needs to be travelled to catch prey, reduced possibility that scavengers will take prey, reduced likelihood of being killed during attack

Question 17

What two hypotheses were proposed in a paper by MacNulty et al, 2011 to explain why there was a decrease after a threshold in the effect of group size on hunting success?

Answer 17

Interference hypothesis- proposed that after a certain threshold, actions of others in the hunting group will interfere with the hunt for the rest of the group and will lead to decreased hunting success- also proposed that this will lead to increased latency for each stage of the hunt with inept or inexperienced hunters interfering

Free rider hypothesis- proposed that above a certain group size, individuals in the group will withhold effort and free-ride from the actions of others in the group- predicted that free riders will hold back at stages of the hunt that are riskier

Question 18

At what point did the number of wolves peak for hunting success?

Answer 18

4- above this number the addition of wolves to the group did not have a positive effect on the hunt

Question 19

What was examined in the study on zebra lionfish and cooperative hunting?

Answer 19

Zebra lionfish were studied by Lonnstedt et al; was shown that lionfish cooperate with conspecific and heterospecific lionfish using a flared fin motion- in this motion, lionfish perform a flared fin motion to recruit other lionfish to help them attack. When an experiment was done with a freckled grouper and an empty tank, no behaviour was observed. Prey were shared equally between the two.

Question 20

What is the flared fin motion used by cooperatively hunting lionfish to recruit a hunting partner?

Answer 20

Caused when one lionfish approaches the other head on, with its head down and pectoral fins raised and it rapidly undulates its pectoral fin for 3-9 seconds before doing a slow separate waving movement of the pectorals