W11L1 Cooperation Flashcards
Why is natural selection is based on cooperation
- genes cooperate in a genomes
-Cell cooperate in an organism
-individuals cooperate in society
The architecture of complexity is based on cooperation
Bacteria cooperate
- Individually costly behaviours that have evolved (to some extent) to benefit recipients
- Production of ʻpublic goodsʼ very common
- Provides group benefit; open to exploitation
Social insect
- Workers do not reproduce, but raise the offspring of another individual, the queen
Hamilton rule
rb > c
r = coefficient of relatedness
c = cost of cooperation
b = benefit of cooperation
What condition are required for kin selection
Novel prediction from Hamilton rules
(1) cooperative behaviour can evolve, if indirect benefits outweigh direct costs
(2) cooperative behavior is favored more, if it is directed to close kin
r= 1 for identical twins
= 1/2 for full sibs, parent-offspring
= 1/4 for half sibs, grandparent/grandchild, niece/nephew
= 1/8 for first cousins etc.
Does Hamilton’s rule explain why cooperation evolved independently so frequently in the hymenoptera?
-all Hymenoptera are haplodiploid
Females – diploid 2n (sperm fertilizes egg) produce eggs by meiosis
Males – haploid n (from unfertilized egg) produce sperm by mitosis (all identical)
-high degree of relatedness between sister 0.75 so help mother to make more sister
How does kin recognition work
- Proxies of relatedness (reared together therefore related)
- The “armpit effect” (be kind to neighbours who smell similar to you).
- Cuticular hydrocarbons of insects
Example for proxy of relatedness : naked mole rat
- Eusocial
- 70-300 per colony
- One ‘queen’ and few fathers
- All closely related
- Communal caring of pups
- Also keep each other warm
Diagram of social interaction
- both benefit: mutualism
- benefit to the receipiant but not the provider: altruism
-benefit to the actor not the receipient: selfishness
-negative to both: spite
Altruism
- Altruism (e.g. helping to raise other’s young) is costly (-) to actor, beneficial (+) to recipient
- Hallmark of cooperatively breeding animals, humans
- If natural selection favour individuals that maximize own fitness, how can altruism and cooperation evolve?
How does cooperation among unrelated
individuals evolve?
-Kin selection: helping relative
-Mutualism: win-win
- Manipulation: deception or force cooperation
-reciprocity
Action of intraspecific cooperation between non-relative
Unrelated helpers in cooperative breeders
Food sharing
Alarm calling
Coalitions
Allogrooming
interspecific mutualism
Cleaning relationships
Protection-provisioning
Insect-plant mutualisms
Method and example of manipulation
- Cooperation may be due to coercion or deception (+/+) because otherwise (-/-)
e.g. Cuckoo chick
e.g. Cooperative cichlids: ‘pay to stay in group’
e.g. Fish size hierarchies: threat of eviction