Transcript FW 491 – Online Ecological Module

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:
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–
–
–
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