Lecture 2 - inclusive fitness theory and practice Flashcards
who was the first person to tackle the paradox of cooperation?
darwin 1859 - he was aware of mutualisms and believed there must be a selfish element of any structure
he became very close to what is now known as kin selection theory
what became the issue in understanding cooperation in the 19th century?
Became very focused on competition and little emphasis was put on cooperation culminating in social darwinism and eugenics (francis galton)
what was peter kroptokins view?
started to put more emphasis on cooperation instead of competition however he … used philosophical and social argument and provided no evolutionary mechanisms
the dark ages of evolution were thought of as before what synthesis came about?
neo-Darwinian modern synthesis that brought together natural selection, Mendelian genetics and population genetics in 1930s-1940s
who were the two founds of the neo-darwinian modern synthesis?
- RA Fisher (1890-1962)
- JBS Haldane (1892-1964)
what idea did the neo-darwinian modern synthesis establish?
Traits favored by natural selection are those that enhance individual fitness - this was established mainly by fisher he also considered that there can be indirect effects in which an animal favors or impedes the survival or reproduction of its relatives
what did haldane start to come up with?
started to come up with the idea now know as inclusive fitness where the level of relatedness effects how you act - Q. Would he lay down his life for his brother?
-A. “two brothers or eight cousins”
what did hamilton come up with?
Saw social interactions everywhere, and potential for an evolutionary theory of altruism= inclusive fitness theory
describe the inclusive fitness theory
shifting the focus from the individual and down to the area of the gene – i.e. genes for altruism spreading throughout the population
- your fitness is not only to do with your offspring but also the offspring of any of your relatives
inclusive fitness theory states that a gene can increase transmission to the next generation by increasing fitness of?
1) direct fitness - individual it is in
2) indirect fitness - individuals with copies of that gene (kin selected fitness)
what is it called when you combine direct and indirect fitness?
inclusive fitness
how does hamiltons view differ from fishers?
hamilton talks of inclusive fitness vs fisher talks of ONLY personal(individual) fitness (direct - no help from actor to recipient)
what can personal fitness also be known as?
neighbour-modulated fitness
what are the 4 outcomes in hamiltons table of social interactions?
1) mutually beneficial
2) altruistic
3) selfish
4) spiteful
what is the official definition of cooperative behaviour?
Cooperative behaviour benefits another individual and has been selected for, at least in part, because of its beneficial effects on the recipient
which two social interactions are examples of cooperative behaviour?
1) mutually beneficial
2) altruistic
what can inclusive fitness be applied too?
Inclusive fitness is very general, it can be applied to actions whose effects on recipients are negative rather than positive
what is the problem of measuring fitness?
In practice, measuring inclusive fitness may be hard to measure – you need to know relatedness and the reproduction of the actor and recipient etc
what is hamiltons rule used for?
used to understand whether a social trait is adaptive or not
what is hamiltons rule?
altruisms evolves if rb>c or rb-c>0
r= relatedness between actor and recipient
b= fitness benefit to the recipient
c= fitness cost to the actor
describe the example of kin selection in turkeys?
turkeys Males form coalitions to court females
- dominant gets all matings – the males in the coalitions are closely related – benefit to dominant male have a subordinate male by his side – can work out costs and benefits by using Hamiltons rule – solitary males are very unsuccessful so the cost is small and therefore outweighed by kin-selected benefit
estimating fitness is challenging, what are solutions to the problem of measuring fitness?
- Productivity of offspring, not adults, in lifetime
- Snapshot of productivity (some have long lifespans)
- single season or reproductive attempt
- offspring condition
- mating success (assume mating success is correlated with fitness)
- Survival across a discrete time interval
- Energy budget, food intake, etc…
what behavioural phenomena has inclusive fitness helped us understand?
1) sex allocation
2) selfish genetic elements
3) parasite virulence
4) conflict resolution
5) spite
6) evolution of sociality
what are two important point to consider regarding inclusive fitness theory?
1) inclusive fitness is entirely general in that it applies to negative aswell as positive interactions among individuals
2) the logic is deceptively easy but the practicalities of measuring direct and indirect components of inclusive fitness are challenging
what are major evolutionary transitions regarding the evolution of life on earth?
- origin of chromosomes
- origin of eukaryotes
- origin of sex
- origin of multicellularity
- origin of social groups
- origin of human society/language
what does each evolutionary transition involve?
cooperation
- so social evolution theory explains each transition using the logic of inclusive fitness theory
what was the hypothesis for the origin of mutlicellularity - Why should single cells join to become mutually dependent? ?
High relatedness between cells played key role in transition to multicellularity
describe ratcliff 2012 study investigating the role of relatedness in the transition to multicellularity
Selected for multicellularity in unicellular yeast
found multicellular traits:
- deferred reproduction
- division of labour (apoptosis)
- over 60 selection intervals they scooped away the top of the yeast and left any yeast cells clustered at the bottom of the culture – gravity was the selective agent for multicellularity/aggregation – at the end they looked for multicellular traits
- Multicellular clusters form by clonal adhesion – high relatedness
- If it was aggregation you would expect low relatedness
- This model shows that high r is important for the multicellular traits
what was fishers approach in understanding the origin or multicellularity?
comparative analysis (Fisher et al 2013) – Compare multicellular form in clonal (r = 1) and non-clonal (r < 1) taxa
what is the cooperative transition from unicellular organisms to mutlicellular organisms influenced by?
relatedness - determined by the process of group formation
