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2nd Year: Evolutionary Genetics > Kin selection > Flashcards

Flashcards in Kin selection Deck (26)
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1
Q

Give 2 examples of cooperation between animals.

A
  1. Slime moulds: in times of starvation will differentiate into cells in a fruiting body and disperse to new areas
  2. Honey pot ants: eat lots and store it in abdomen, regurgitate for others in times of starvation
2
Q

Give 2 examples of animals that display eusociality.

A
  1. Order hymenoptera

2. Naked mole rats

3
Q

Define eusociality.

A

Organisms form colonies in which there is a division of labour and cooperative brood care.

4
Q

Define cooperation.

A

Both the actor and recipient of the behaviour benefit.

5
Q

Defection from a cooperative strategy is often advantageous for the defector. True or false?

A

True.

6
Q

How did cooperation evolve?

A

Repeated interaction leads to reciprocity. Individuals are more likely to cooperate if they know they will gain a direct selfish benefit.

7
Q

Define altruism.

A

An entirely selfless act that harms the actor.

8
Q

Altruism is observed in eusocial insects. Why is altruism thought to have evolved?

A

Because of kin selection.

9
Q

Define inclusive fitness.

A

Fitness is seen as the transmission of genes.

10
Q

What is a) direct and b) indirect inclusive fitness?

A

a) Direct: transmission of genes via offspring

b) Indirect: if an organism helps to raise the offspring of another with the same genotype, e.g. their sibs.

11
Q

In a monogamous population, what is the proportion of relatedness an organism shares with a) its siblings or b) its offspring?

A

They are both the same, 1/2 related.

12
Q

Thus what can be said about monogamous populations in terms of genes?

A

There is ‘equality of genetic worth’.

13
Q

Altruism generally arises in monogamous or ancestrally monogamous populations. Why?

A

Because the actor still has inclusive fitness by helping to pass on some of its genes.

14
Q

Give Hamilton’s rule and explain it.

A

rb > c

Says that relatedness x benefit is greater than cost, i.e. the actor may not benefit directly but the relatives will from its actions.

15
Q

Under Hamilton’s rule, who are the interactions between if a) r = 0, b) r = 1/2 and c) r = 1.

A

a) random individuals
b) full sibs
c) clones

16
Q

The more closely related individuals are, the more beneficial it is to be altruistic. True or false?

A

True - this was shown in an experiment with slime moulds. Newly evolved cells would migrate to the fruiting body and ‘sacrifice’ the cells in the stalk because they were less related.

17
Q

Dispersal is a costly behaviour. Why is it seen in nature?

A

It reduces kin competition.

18
Q

When the benefit is large there is a higher rate of dispersal. True or false?

A

True.

19
Q

Define spite.

A

The actor sabotages the recipient to reduce competition, although there are often costs for them too.

20
Q

The effect of spite is increased in large populations. True or false?

A

False - the effect of spite is diluted in large populations.

21
Q

Spite requires genetic recognition cues. Why?

A

So the actor does not sabotage a relative.

22
Q

What are genetic recognition cues likely to be?

A

Pheromones.

23
Q

Genetic recognition cues are often referred to as what?

A

‘Green beard’ or ‘selfish’ genes.

24
Q

Briefly outline the study on South African fire ants which is an example of a selfish gene.

A
  1. 2 social forms of ant that differ in a single locus
  2. One form is monogynous (1 queen), both queens and workers are homozygous dominant.
  3. Second form is polygynous (many queens), both queens and workers are either homozygous dominant, heterozygous but homozygous recessive is lethal.
  4. Heterozygotes of the polygynous colonies will murder monoygnous queens. It is thought it is because they possess a recessive allele which has been identified as the selfish gene.
25
Q

At which locus do the 2 social forms of South African fire ants vary?

A

Gp9 marker locus.

26
Q

Upon further study of the Gp9 locus it was found that it is not a single gene, but a large inverted sequence that cannot recombine. This has been termed as what?

A

A social chromosome.