Animal Behaviour-Co-operation between related individuals

Question 1

What is altruism?

Answer 1

A behaviour that is costly to the actor with no benefit

Question 2

What does the Wynne-Edwards model show?

Answer 2

That a group that co-operates does better than a group of selfish individuals. This is because the selfish individual over exploit a resource and die out whereas altruistic individuals share the resources and do not over exploit them

Question 3

What is the problem with the Wynne-Edwards model?

Answer 3

Selection acts on individuals and not groups which means if a selfish individual invades an altruistic group, it will do better (basically it is not an ESS)

Question 4

For co-operation to occur, what factor must outweigh what?

Answer 4

Benefits to the individual must outweigh the cost (e.g a prisoner is going to sell out for a bigger pay off so will need something better if they are to co-operate with other prisoners/criminals)

Question 5

Why do a lot of animals show co-operation with individuals which are genetically more similar/ more related to them?

Answer 5

Because full fitness can be achieved (passing on all of your genes) through others such as siblings without you having offspring of your own. This is called inclusive fitness or kin selection (e.g Zoe has half of my genes. Each of her children will have half again so a quarter of mine. If she has four children, all of my genes will be passed on)

Question 6

What is Hamilton’s rule?

Answer 6

rB-C>0

The more related the actor is to the recipient, the bigger the cost can be

Question 7

How do we calculate r (relatedness) in Hamilton’s rule?

Answer 7

r = Σ (0.5)L
where L is a generation link, sum across all possible pathways
E.g grandparents to an individual = 0.25
This is because r=1(one pathway) (0.5)^2 as it’d across two generations

Question 8

Can you state the r value for offspring and full sibs, grandchildren and half sibs/nephews/nieces, great-grandchildren and cousins?

Answer 8

0. 5= full sibs and offspring
1. 25= grandchildren and half sibs, nephews and nieces
2. 125= great grandchildren and cousins

So iffor example an actor died in an altruistic act to save some relatives, those genes will increase the gene pool if the acted benefited >2 full sibs or for example >8 cousins

Question 9

Name a non-animal organism which co-operation increases with relatedness.

Answer 9

Bacteria produce more ‘public goods’ when around related individuals

Question 10

There was uncertainty about whether discrimination cannibalism in salamanders was due to kin selection or whether sibs didn’t eat eachother due to other direct benefits such as avoidance of pathogens/parasites. What was the outcome of the study?

Answer 10

Showed it was due to kin selection which was evident because the benefits outweighed the costs of being a discriminator. Being a discriminator (choosing not to eat sibs) was not very costly at all

Question 11

Do animals which co-operate have to be social?

Answer 11

No, red squirrels are not but help eachother thermoregulate by communal nesting in cold weather. The females pair up. They are usually closely related

Question 12

Prairie dogs call to raise awareness of a predator. (These alarm calls can be different depending on what predator is present). What is the trend of how much females and males call if there are their offspring in the group? If there are offspring of relatives? If there are no related offspring?

Answer 12

If their offspring are in the group, females and males call 50% of the time (so share it equally). The rates are similar if it is offspring of their relatives. If there are no related offspring present, calling still happens but at a reduced rate. Also males tend to call more than females in this last case

Question 13

Why do prairie dogs still call when there are no related offspring present?

Answer 13

May benefit the individual by warning off the predator

Question 14

How do animals recognise kin? What was shown about conflict/ antagonistic interactions of sibs raised together and those raised apart?

Answer 14

Odour cues (for those siblings raised apart) and learning familiarity (for those raised together). Much more conflict between sibs raised apart. Also found this in non sibs

Question 15

What are ‘greenbeard’ genes? Can you give an example of an insect which use these?

Answer 15

Genes which allow recognition by other individuals and induce co-operative behaviour to one another.

E.g Fire ants attack a queen without a b allele of the GP-9 locus

Question 16

Why are ‘greenbeard’ genes not commonly seen?

Answer 16

Very complex. Requires 1 gene to be involved in signal production, recognition and co-operative behaviour. Also very susceptible to cheating/faking

Question 17

How did monogamous and polyandry birds show how co-operation can be dependent on mating systems?

Answer 17

Birds which are monogamous will produce a set of full sibs which are more likely to co-operate than a polyandrous bird which will produce many more distantly related birds that may not co-operate as much

Question 18

How do Seychelles’ warblers show how mating systems can influence co-operation?

Answer 18

Warblers can breed at a year old but a lack of suitable habitats mean that they often help relatives. Females ar more likely to help closer relatives (through feeding for example). They are also more likely to help if their mother is the dominant female doing the reproducing.

Question 19

Male warblers do not help as much with offspring as they try to mate many females. Why might helpers still help less related sibs?

Answer 19

Indirect benefits (kin selection) is still beneficial

Question 20

Breeding by subordinates in meerkats (those that are not dominant) are policed by dominant members (they may kill the offspring or evict the pregnant subordinate). Why?

Answer 20

It is costly for the dominant female if her helpers do not share their resources as much with her. To pay their way back into the group, meerkats allolactate (directly feed the offspring of the dominant female). It is beneficial for both members as pregnant subordinates won’t survive alone

Question 21

Give an example of an extreme co-operative system in eusocial insects?

Answer 21

Bees,wasps. Co-operative care of young, sterile workers and one queen that produces offspring, overlapping generations.

Question 22

Haploidiploidy in Hymenoptera can result in males developing from unfertilized eggs therefore being haploid and only having genes from the mother. What does this mean in terms of relatedness between sibs?

Answer 22

It means that females get all of their father’s genes (0.5) and half of their mother’s (0.25) which mean female workers are more related to their sisters (0.75) than to their own offspring. It is therefore more beneficial to rear her sisters than producing offspring herself

Side notes- policing of worker offspring is again evident in his species