up until midterm

61 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences
Maydianne Andrade

LECTURE 1 Evolutionarily stable strategy - set of rules of behaviour that when adopted by a certain proportion of the population cant be replaced by any alternative strategy Why study animal behaviour Know how to breed animals, when will animals attack, what characteristics are needed in nature reserves to save endangered species, humane way to house animals, stop damage by pest species... OPOSSUMS Play dead when scared - why? Predator thinks dead, not appetizing Not many scavengers around Learned it was a good strategy (less likely to be killed by predators) Inherited behaviour from ancestors Pass out from terror TWO CATEGORIES OF QUESTIONS PROXIMATEULTIMATE CAUSATION PROXIMATE How - physiologicalcognitive mechanisms Developmental processes (ontogeny [see others doing it so you do it too], genetics) Eg - possums play dead because the sight of a predator triggers a physiological response that causes them to lie down and remain motionless ULTIMATE causes Why questions - evolutionary history (origins, change over time) Effects on fitness (current or recent function) Eg - possums play dead because over evolutionary time, those possums that did play dead were more fit than those that did not www.notesolution.com 4 LEVELS OF ANALYSIS - complementary answers to the question WHAT CAUSES ANIMAL A TO EXHIBIT TRAIT X? 1. Mechanistic reasons (how does it work) 2. Ontogenic reasons (how does the trait develop during a lifetime) 3. Fitness consequences (is it favoured by natural selection and why) 4. Origins (what were the evolutionary precursors to this trait) An answer at 1 level of analysis does not rule out answers at another level!!! Eg - why is this man smiling Mechanistic - neurons fire in brain, causes facial muscle contractions Ontogeny - learn when to smile in the right context by adults (as baby smile only asd reflex - adults teach babies to smile in response to people Function (fitness consequences) - smiling makes you more attractive to opposite sex Origin - originated as social signal that you are not dangerous to another person FOCUS IS FUNCTION ( fitness) DARWINS POSTULATES 1. Variation exists among individuals in a species 2. Some variations are heritable 3. Not all individuals survive 4. Survival and reprod are NOT RANDOM - individuals with fabvorable traits produce more offspring Animals posess traits that MAXIMIZE FITNESS!! Traits that lead to increased success become more common in populations Evolution by natural selection predicts animals posses traits that MAXIMIZE LIFETIME REPRODUCTIVE SUCCESS FITNESS www.notesolution.com Relative contribution of genes to future generations Lifetime reprod success relative to competitors MEASURED BY Factors that are related to fitness (difficult to measure fitness directly) Survival to breeding, mating success, # offspring per season, total offspring, susceptibility to disease, number of parasites, prey captured... RELATIVE to others in the population BEHAVIORS CAN EVOLVE - leads to adaptive behaviours!! (behaviours that increase fitness) ASSUMPTION THAT BEHAVIORS EVOLVE TO INCREASE REPROD SUCCESS Behaviours evolve when 1. They are variable within the population 2. Variants are heritable 3. Behaviour effects LIFETIME REPRODUCTIVE SUCCESS Evolution of BEHAVIOR by nat selection leads to adaptive behaviours that increase reprod of those that posess them relative to competitors Hypothesis testing Asking questions about behaviour using the scientific method Generate many competing hypotheses (AT ONE LEVEL OF ANALYSIS), outline predictions (if...then), test predictions, make conclusions about hypotheses INFANTICIDE Langurs (monkeys) 2 types of troops (all male group, male female mix group [25 female relatives, 1-3 adult males]) When they encounter eachother they are very aggressive www.notesolution.com
More Less

Related notes for BIOC54H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.