Class Notes (810,488)
Canada (494,139)
Biology (2,097)
BIO318Y5 (33)
Lecture 11

BIO318 Lecture 11 (Oct 16).docx

4 Pages
Unlock Document

University of Toronto Mississauga
Sanja Hinic- Frlog

BIO318 Lecture 11 - Past stories o Marsupials mouse die after mating - Extreme sex differences in lifespan: semelparous male marsupials (family Dasyuridae) o Successful males copulate frequently (up to 14 hours per bout) o Testosterone and stress hormones increase rapidly and they senesce quickly; immune systems compromised and then most males die after mating o Semelparous (mate once) - Their explanation o Not group-selected altruism whereby males sacrifice themselves to lower food competition to benefit the group (lemming cartoon) o Similar to “adaptive suicide” in redback spiders (to increase paternity): in “predictable food” habitats, females have evolved short breeding seasons and thus enhance fitness by mating with “extreme promiscuity”= severe sexual selection on males o Females may mate with multiple males to increase the sperm pool for her offspring - Arthropod o Spiders and insects o As breeding length increases, prey abundance decreases; so when arthropods are highly preyed upon, their breeding season will be much shorter in order to reproduce and pass on genes to the next generation o Correlation only; doesn’t mean causation - Last lecture o Bias towards females o Some males have more daughters than sons o Bias in sex ratio appears to be a balance of individual and selfish gene selection o Selfish genes on the X o Selfish gene does not go to fixation (and thus population extinction) because of opposing individual and gene selection - Levels of selection - Altruism o Reveal conflict for the group but not good for the individual - Cylinders represent the different ponds o Altruism and selfish individuals o When a pond is only selfish individuals, they go extinct because they die o When there’s at least one altruistic individual, the group survives o Group level selection o IN THEORY: differential success among groups affects change in the gene pool - Fitness in conflict o Gene vs individual vs group (revealed in certain traits such as sex ratio and altruism) o Male vs. male o Male vs. female: we have already noted genes for ornament/armament in males that likely decrease
More Less

Related notes for BIO318Y5

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.