Download - Day 19 chapter 14 november 18th
Day 19 Chapter 14 November 18th
Dr. Amy B Hollingsworth
The University of Akron
Fall 2014
• Exam scores were released. Overall, they were WAY better than exam two, so YAY!
• 65 questions, I threw out 9, total out of 56 questions.
• Final Exam – Chapters 14, 15, 16 in CBT during finals day -
Chapter 14: Population Ecology
Planet at capacity: patterns of population growthLectures by Mark Manteuffel, St. Louis Community College
14.1–14.6
Population
ecology is the
study of how
populations
interact with their
environments.
14.1 What is ecology?
14.2 A population perspective is necessary in ecology.
14.3 Populations can grow quickly for a while, but not forever.
There is no exception to the rule that every organic being naturally increases at so high a rate that, if not destroyed, the Earth would soon be covered by the progeny of a single
pair.
—Charles Darwin, The Origin of Species
In stable populations,
How many of the five million eggs that a female cod might lay over the course of her life will, on average, survive and grow to adulthood?
Who leaves more surviving offspring, a pair of elephants or a pair of rabbits?
14.4 A population’s growth is limited by its environment.
Density-dependent Factors
The limitations on a population’s growth that are a consequence of population density
This ceiling on growth is the carrying capacity, K, of the environment.
Density-independent Forces
Factors that strike populations without regard for the size of the population
Mostly weather-based
How many people can earth support?
Why does the answer keep increasing?
14.5 Some populations cycle between large and small.
Do lemmings jump off cliffs committing suicide when their populations get too big?
14.6 “Maximum sustainable yield” is a useful but impossible-to-implement concept.
Almost all natural resource managers working for the U.S. government fail to do their job exactly as mandated.
Why?
What We Often Do Not Know…
Population carrying capacity
Number of individuals alive
Stability of carrying capacity from year to year
Which individuals to harvest
14.7–14.9
A life history
is like a
species
summary.
14.7 Life histories are shaped by natural selection.