BIOL-208 Lecture Notes - Lecture 8: Inclusive Fitness, Natural Selection, Reciprocal Altruism
17 Dec 2016
School
Department
Course
Professor
Behavioural Ecology
- Evolution and behaviour
- “Natural selection favours those behaviours that increase the inclusive fitness of
individuals” In other words, natural selection acts on individuals, causing
evolution within populations
- Behaviours with genetic bases
- Ground squirrels: one will be on watch, makes noise to warn other of
predators, putting self in danger by being noisy
- 50 years of research: adaptive value of a given trait is often contingent upon the
specific environmental conditions that an organism faces; environment is driving
behaviours
- Certain behaviours are more adaptive than others; circumstance specific
- Nature or nurture is an out of date debate
- Evolution fine tunes process
- Sets threshold of risk
- Based on local conditions
- Creates variation in behaviours
- Intraspecific (within species)
- Interspecific (between species)
- Squirrels crossing roads, those that cross a lot are more likely to be
runover and killed by vehicles, so they are no longer in the gene pool.
Those that are more cautious and don't cross roads as much survive and
reproduce, increasing the number of individuals who are cautious
- Inclusive fitness
- An individual's overall fitness determined by survival and reproduction
includes themselves and all relatives
- Kin selection: selected for helping relatives; having an inclination to help
family first - hierarchy of who to help first
- Selfish behaviour (evolutionary point of view): when helping relatives, is
actually selfish to help self gain inclusive fitness
- Four main classes of social interaction
- Benefits both donor and recipient: cooperation
- Benefits donor, harms recipient: selfishness
- Harms donor, benefits recipient: altruism
- Harms both donor and recipient: spite
- Altruism and natural selection
- Kin selection related
- Coefficient of relationship: relatedness of two individuals; 50% parent-
offspring, 25% grandparent-grandkids
- Altruistic behaviour if cost/benefit is less than coefficient of relationship
- The less related an individual is, the less likely they’ll help if in
need
- Shown in squirrels adopt babies if genetic parent dies
- Altruism and manipulation
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Natural selection favours those behaviours that increase the inclusive fitness of individuals in other words, natural selection acts on individuals, causing evolution within populations. Ground squirrels: one will be on watch, makes noise to warn other of predators, putting self in danger by being noisy. 50 years of research: adaptive value of a given trait is often contingent upon the specific environmental conditions that an organism faces; environment is driving behaviours. Certain behaviours are more adaptive than others; circumstance specific. Nature or nurture is an out of date debate. Squirrels crossing roads, those that cross a lot are more likely to be runover and killed by vehicles, so they are no longer in the gene pool. Those that are more cautious and don"t cross roads as much survive and reproduce, increasing the number of individuals who are cautious. An individual"s overall fitness determined by survival and reproduction includes themselves and all relatives.
