Lecture 6 E

Question 1

What are the benefits of being a solitary vs social species

Answer 1

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Increased ability to cooperate in finding food
Increased ability to cooperate against predators
Increased likelihood of finding a mate

Question 2

What is Eusociality

Answer 2

adult members are divided into reproductive and (partially) non reproductive castes. And the latter care for the young.

Question 3

Give some examples of eusociality (superorganisms)

Answer 3

All termites
All ants
Two species of mole rates
Some aphidae

Question 4

What is kin selection theory?

Answer 4

Kin selection theory is based on the concept of…

-inclusive fitness: sum of the effect of an action on the actors own fitness (direct fitness) and on the fitness of the recipient (indirect fitness) multiplied by the relatedness between actor and recipient.

Question 5

What is hamiltons rule?

Answer 5

R>c/b

C: cost to the actor
B: benefit to the recipient
R: fraction of the genes shared between the actor and the recipient

Question 6

Altruistic cooperation is favoured by natural selection if what?

Answer 6

If the genetic relatedness is greater than the cost to benefit ratio

The more genes shared with another individual the higher the interest in helping them

Question 7

What is the haplodiploid hypothesis?

Answer 7

Females develop from fertilised eggs

Males develop from unfertilised eggs
They have a mother but no father and cannot have sons but can have daughters
No meiosis takes place so all gametes are identical
Each of their daughters received identical set of genes

Question 8

What is a diploid species?

Answer 8

Normal!
Offspring receive 0.5 of genetic material from mother, 0.5 from father

Full sibling relatedness (R) =0.5

Question 9

Eusocial insects

Answer 9

• Many adults live together in a group
• Overlapping generations
• Cooperating making adults in nest-building and care of young
• Reproductive dominance
• Sterile castes (in some species)
• Devision of labor

Question 10

What are the requirements of eusociality?

Answer 10

Overlapping generations
High effort expended in parental care
Non-reproductive can aid in parental care

Question 11

When do animals form groups?

Answer 11

• Nests sites or food sources on which a species is specialised are local in distribution
• Parents and offspring stay together
• Flocks follow leaders to know feeding grounds
• Randomly by mutual local attraction

Question 12

Why has eusociality evolved?

Answer 12

1. The formation of groups
2. The occurrence of pre-adaptive traits, causing the groups to be tightly formed
3. The appearance of mutations that prescribe the persistence of the group
4. Emergent traits caused by the interaction of group members are shaped through natural selection by environment forces
5. Multilevel selection drives changes in the colony life cycle and social structures

Question 13

What are the cost of being a solitary vs social species

Answer 13

-
Increased intraspecific competition
Increased risk of disease
Increased risk of detection by predators

Question 14

What are super organisms?

Answer 14

“Superorganisms” emerging from eusociality represent a distinct level of a biological organism

Question 15

Fitness is increased by what?

Answer 15

Individual reproduction (directly) or the reproduction of close relatives (indirectly)

Question 16

What are the ecological pressures for Eusociality?

Answer 16

Ecological pressures

• nest defence
• low opportunity for young to disperse
• need to cooperate to rear young