Please pass back the new objective sheet.

Please get out your signed permission slip and $15 for pick up.

Take your “Tradeoffs- Sage Grouse and energy” reading packet and answers to the back lab table. Staple them together and put them in the white bin.

Only 6 more days to get that

permission slip turned in!

What do you think of this?

WHAT ARE THE RULES? THEY DON’T APPLY TO US, DO THEY?

Population Ecology

Rule #1: Populations will grow exponentially

according to their biotic potential

Linear growth vs. exponential growth

Biotic potential – capacity for growth

Age at reproductive maturity

Generation timeTime between

reproductive eventsOffspring per

reproductive event

Rule #2: Populations cannot increase

indefinitely

Sigmoidal growth – the S curve

Carrying capacity

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

Subtle details!

At carrying capacity (K), individuals are still dying and being born. The total population size is constant.

Populations do not know when they’ve reached K

Populations cycle above and below K several times before leveling out.

Limiting factors set the carrying capacity

Two categories of limiting factors

1. density-independent limiting factorsNatural disastersClear cutting

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

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

genes into the next generation

Reproductive similarities?

Reproductive similarities?

Opportunists vs. Competitors

Survivorship curves

Rule #4: Predator and prey develop a predictable

pattern.

Lotka-Volterra model

Soooo . . . Good thing we’re human and these rules don’t

apply to us . . . Right?

Or do they? What part(s) of the sigmoidal curve do you see?

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?