Textbook Notes (368,720)
Canada (162,105)
Biology (600)
BIO120H1 (305)
Chapter

BIO120 Online Readings #2

4 Pages
152 Views
Unlock Document

Department
Biology
Course
BIO120H1
Professor
Paul Thompson
Semester
Fall

Description
Survivorship Curves 10 Introduction • Survivorship curves describe survivorship in a given cohort • Can be affected by both biotic and abiotic factors; competition and temperature Idealized survivorship curves - type 1 " high survivorship throughout the life cycle • Type II - constant proportion dying overtime • Type III - high mortality at young age • Must be done on a log scale not a linear scale Human Survivorship Patterns • Demography: study of characteristics of human populations • Developed like type I 11 Semelparity and Iteroparity Semelparity • Death after first reproduction, iteroparity is reproducing again and again • monocarpy or polycarpy -> same thing and sp and ip Dilemma and Cost of Reproduction • semelparous species produce more in one offspring than similar organisms do • this is a fecundity advantage • "Under what conditions does the increase in fecundity associated with semelparity more than compensate for the loss of potential subsequent reproductive episodes?" Theoretical Approaches 1.Demographic models: when adult survival is lower than juvenile survival; favour sp 2.Bet hedging models: when adult survival is highly variable; ip 3.Non linear pattern models: costs of reproduction happen at low levels of reproductive effort Empirical Evidence • All show semelparity is more likely in species where adult survivorship is low Synchronous Semelparity - Species " Approaching" Semelparity - Semelparity in Grain Crops 12 Causes and Consequence
More Less

Related notes for BIO120H1

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit