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.