Cooperation II

Question 1

Three key approaches in social evolution

Answer 1

1. Inclusive fitness approach
2. Neighbour modulated fitness approach
3. Multi level (group) selection approach

Question 2

What is the theory of inclusive fitness?

Answer 2

An organism’s genetic success is believed to be derived from corporation and altruistic behaviour

Question 3

Direct fitness

Answer 3

Measure of individuals direct reproductive success in passing on genes through offspring production

Question 4

Indirect fitness

Answer 4

Genes contributed to the next generation by an individual via helping relatives (so indirect because help relatives which then produce offspring - the helper itself doesn’t produce offspring)

Question 5

Inclusive fitness

Answer 5

The sum of an individuals direct fitness and indirect fitness

Question 6

What’s an explanation for altruism?

Answer 6

Inclusive fitness - being altruistic and helping others is worth it if it means it can help pass on your own alleles (if u r the same species)

Question 7

Altruism

Answer 7

Animals help other individuals increase their fitness at a cost to themselves

(Reducing my direct fitness to increase a relatives fitness)

Question 8

What is Hamilton rule

Answer 8

An equality:

r B < C

r - relatedness
B - benefit to recipient
C - cost to the altruist

Question 9

What does Hamilton rule tell us?

Answer 9

It tells us when altruism is expected to be selected for in a population

Question 10

What does relatedness mean in Hamilton rule?

Answer 10

Proportion of alleles shared between altruist and recipient of altruistic behaviour

Question 11

What does benefit to recipient mean in Hamilton equation

Answer 11

Number of offspring produced by recipient that wouldn’t have been able to be produced without help of altruist

Question 12

What does cost mean in Hamilton equation

Answer 12

How many offspring the altruist is unable to produce as a result of altruistic behaviour

Question 13

When does Kin selection occur

Answer 13

When an individuals inclusive fitness is increased by engaging in altruistic behaviour that enhances reproductive success of relatives

Question 14

What is meant by relative?

Answer 14

Are they more genetically similar than average in the population

Question 15

Definition of relatedness

Answer 15

Probability
Above average
That actor and recipient share alleles at a focal locus

Question 16

How closely related are

Clones
Siblings
Half siblings
Non relatives

Answer 16

Clones 1
Siblings 0.5
Half siblings 0.25
Non relatives 0

Question 17

What is kin selection THEORY

Answer 17

Anything that has a focus on relatedness

Neighbour modulated/inclusive fitness theory

Question 18

What is kin selection PROCESS

Answer 18

Natural selection involving non zero relatedness

Involving individuals related above 0 - aka so must be clones/siblings/half siblings etc

Question 19

What is multi level group selection

Answer 19

The help doesn’t go to one specific individual; it goes to a group (which includes the actor - the one giving the help)

Eg. Bacteria makes enzyme that they put out into environment. Enzyme breaks down food so other bacteria can pick up nutrients as well.

Question 20

Workers raising queens offspring

Q - If we were going to model this what framework would be used?

Answer 20

Inclusive fitness because they are all related

Inclusive fitness is a way to understand social insects

Question 21

What’s the best way to model the selfishness by transposons as they jump and harm the genome?

Answer 21

Group selection because the genome is a group

Key thing - genome of an organism functions as a group - action of an allele on an organisms is felt by everyone including the gene itself

Question 22

Best modelling framework for cooperative secretions of bacteria?

Answer 22

Group selection because the secreting cell can benefit AND other cells can benefit form it’s secretions

Question 23

Best modelling framework for lemmings jumping off a cliff?

XXX

Answer 23

Could use group selection (because lemmings live in groups) or inclusive fitness (because need relatives to benefit form jumping)

Question 24

Classic model used to study altruism in social insects?

Answer 24

Inclusive fitness

Question 25

Why can you also use multi level group selection model to study social insects?

Answer 25

Because insects are in groups and you can think about benefits to the colony

Question 26

Lots of social insect models end up being what

Answer 26

Both inclusive fitness and multi level group selection

Question 27

Three ways indirect benefits can occur

Answer 27

1. Limited dispersal 2. Kin discrimination 3. Green beard

Question 28

Explain how indirect benefit occurs through limited dispersal XXX

Answer 28

44 min 05 don’t get Bacteria make patches - surrounded by relatives - incentive to cooperate

Question 29

Example of how local competition could outweigh indirect benefits?

Answer 29

Bacteria in patches surrounded by relatives = gives them more insentive to cooperate But if they stay localised for too long they might start to compete with their relatives

Question 30

Why do honey bees fight to death even though they are related?

Answer 30

Intense local competition Queens in honey bee colony are sisters or half sisters Only one bee can take over colony Even though they are related they fight to death for the throne

Question 31

Explain how indirect benefit occurs through discrimination

Answer 31

Kin discrimination so help relatives so indirect benefit to the actor because still passing on its genes (just through relatives)

Question 32

What’s Kim discrimination

Answer 32

An individual identifies a relative and then cooperates with them

Question 33

Difference between kin section and kin discrimination

Answer 33

Kin selection = process/modelling framework Kin discrimination = behavioural action to identify relatives

Question 34

Relationship between benefit form helping and kin discrimination

Answer 34

As benefit from helping increases Kin discrimination increases

Question 35

In groups where there are a lot of relatives there is less kin discrimination

Answer 35

Makes sense because if in group with list of relatives it means high probability who u interact with will be a relative anyway

Question 36

When does kin discrimination pay most?

Answer 36

When I’m groups where you don’t know who are your relatives (can’t assume everyone is your relative)

Question 37

How do individuals recognise their kin?

Answer 37

Environmental cues

Question 38

Environmental cue example in ants

Answer 38

Take worker form one ant mount to another ant mound Placed any will get savaged Ants able to protect self and non self Smell different (particular hydrocarbons on the outside)

Question 39

How to bacteria detect kin and non kin?

Answer 39

Using toxin and immunity proteins. Release toxin (kin will have immunity protein so can detect they are kin) Incoming toxins = up regulate own toxins if feel being attacked. (So if they feel they r being harmed then they are aware there is the presence of another genotype - non kin)

Question 40

Explain how indirect benefit occurs through green beard genes

Answer 40

X

Question 41

Flocculation of yeast cells in beer

Answer 41

Stress response in high alcohol concentration yeast express protein causing aggregation then they rip out of solution and it protects them agains harm

Question 42

Example of green beard discrimination in Flo proteins

Answer 42

Mix cells that make Flo protein and cells that do not make it Cells that make it sticks together (So flo protein trait allows for recognition - because aggregation is a result it allows cells to identify other cells with that specific loci) * can also put two difference cell species in test tube both with flo proteins and the different species still aggregate because of the flo protein (demonstration of cooperation driven by a single locus (the locus for the Flo protein))

Question 43

What complex of three effects do green beard genes require?

Answer 43

1) a perceptible trait 2) recognition of this trait in others 3) preferential treatment of those recognised

Question 44

What do the frameworks explain?

Answer 44

why organisms evolve to expend their own resources to help others when it doesn’t seem to directly benefit them

Question 45

Why does the inclusive fitness theory say organisms evolved to be altruistic ?

Answer 45

Because I’m being altruistic they gain indirect benefits and fitness because their genes are still passed on (it’s just through relatives)

Question 46

Why does the multi level group theory say altruism evolved?

Answer 46

altruism evolved because if organisms are as a group it’s beneficial to everyone and worth the cost of having to spend some individual energy towards helping other son the group (This is group mediated fitness)