fw 491 – online ecological module by: jessica caton
TRANSCRIPT
FW 491 – Online Ecological Module
By: Jessica Caton
Introduction to Population Ecology • What is a population?
– A group of individuals of a single species inhabiting a specific area (Molles 2010, p. 202)
• Areas of study involved – Population genetics– Population dynamics
Population Dynamics
An area of population ecology concerned with the factors influencing the expansion, decline, or maintenance of populations (Molles 2010, p. 222)
• Increases = Birth and Immigration• Decreases = Death and Emigration
Population Dynamics (con’t)
Important for ecology to understand/prevent decline and extinction of endangered species
Antarctic Species of Interest:Adélie Penguin
(Pygoscelis adeliae) • Physical appearance:
– Medium-sized (2 feet tall), black and white – Angular head and tiny bill– White eyering – Longest feather on body is the tail
• Smallest penguin in Antarctica
• One of the pack ice Antarctic penguins
• Most numerous bird in Antarctica
Adélie Penguins and Climate Change
• One of the best studied birds
• Changing population of species: numbers dropped a third
• Sea-ice decline, Adélie penguin populations decline
• Evolution of environmental instability?
Life Tables • A table that uses age specific information to estimate important population dynamic traits on a population
• Types of life tables:– a table based on individuals born (or beginning life in some other way) at same time (Molles 2010, p. 230)
– Static life table: a life table constructed by recording the age at death of a large number of individuals; a snapshot of survival within a population during a short interval of time
(Molles 2010, p. 231)
Life Table Summary Time
Cohort (horizontal)
Composite
Time-specific (static, vertical)
Data Collection for Life Table
Variables in Life Tables
• nx
• lx
• mx
• lxmx
• R0
• R0 = ∑lxmx
Survival and Mortality in a Population of Adélie Penguins
(Ainley & DeMaster 1980)
Survivorship Curve
• A graphical summary of patterns of survival in a population (Molles 2010, p. 231)
• Three types:– Type 1 = High mortality in
older individuals– Type 2 =Constant mortality rate– Type 3 =High mortality in juveniles