Warm It Up Answer the following in your notes

spiral:a. Identify a time when exponential

growth can be beneficial.b. Predict the carrying capacity (K) of

this classroom. ;-)

Population Ecology:

What are the rules? They don’t apply to us, do they?

Boy, do I have a deal for you! Choose your preference:

Choice A:I’ll give you $1

every day for the next 10 days

Choice B:I’ll give you 10

cents today and double that every day.

LAW #1: Populations will grow exponentially

according to their biotic potential

Linear growth ($1/day) vs. exponential growth ($0.10/doubles every day)

The

J

Curve

unlimited resources Reproduce early in

life Short generation

time Reproduce often Multiple offspring leads to exponential

growth

Biotic potential or intrinsic rate of increase

LAW #2: Populations cannot increase

indefinitely

Sigmoidal growth model

The

S

Curve

Carrying capacity

The number of individuals of each species that can survive in an area indefinitely.

Set by limiting factors

Two categories of limiting factors1. density-

independent limiting factorsNatural disastersClear cutting

2. Density-dependent limiting factors Food Mates Space DiseaseDisease predators

A.Exponential GrowthB.Actual Logistical GrowthC.Predicted Logistical GrowthD.Linear GrowthE.Carrying Capacity (K)

LAW # 3: There is more than one strategy for getting your

genes into the next generation

Reproductive similarities?

Reproductive similarities?

Opportunists vs. Competitors

5 min. coloring break

Draw your favorite r- and K-selected species

Decorate the picture with reproductive strategies

Survivorship curves

Population density and population distribution patterns affect mating habits.

number of individualsDensity = area sampled

LAW #4: Predator and prey develop a

predictable pattern (Lotka-Volterra Model).

Caption Contest!

Predict the graph of wolf

and moose populations

sizes over 50 years… (sketch

graph it…)

Lotka-Volterra model

Cyclical!

Num

ber o

f ind

ivid

uals

Num

ber o

f ind

ivid

uals

TimeTime

Irruptive

Stable

Cyclic

Irregular

Four Types of Population Curves

Are these logistical or

exponential?

WHY?

What species is this?

What keeps this population “in check”?

Soooo . . . Good thing we’re human and these rules

don’t apply to us . . . Right?

In Closing…Name two density-dependent

and two density-independent factors that apply to humans.

Are we r- or K- strategists? Defend your answer.

How do humans avoid the Lotka-Volterra model (elliptical oscillation)?