Limiting Factors & Pyramids Review

Limiting Factors:A limiting factor is anything that keeps a population from growing larger.

FOOD

WATER

LIVING SPACE

SHELTER

WRITE THIS DOWN:

Two types of limiting factors:

-not based on population size -reduces the size of ALL populations in an area equally-usually ABIOTIC

(weather, pollution, fires)

Density-Independent –

WRITE THIS DOWN:

-affect large populations more often than small ones

-also includes predation, parasitism, and disease

-include things like competition(for food, water, shelter,

and living space)

Density-Dependent –

You Try:Is the following example density

dependent or independent?What is the limiting factor?

THERE IS ENOUGH WATER, SHELTER, AND LIVING SPACE TO SUPPORT A POPULATION OF 100 RABBITS, BUT ONLY ENOUGH FOOD TO SUPPORT 50.

You Try:Is the following example density

dependent or independent?What is the limiting factor?

THE POPULATION OF A POLLUTED RIVER IS DECREASING ANNUALLY. THERE IS LESS BIODIVERSITY AND ALL SPECIES ARE SUFFERING THAT DEPEND ON THE RIVER.

You Try:Is the following example density

dependent or independent?

THERE IS ENOUGH WATER AND FOOD FOR 1,000 BIRDS, BUT ONLY SUITABLE NESTING SITES FOR 100.

Pyramids Review

There are three types of pyramids:

-energy-number-biomass

Pyramids Review

COPY THE FOLLOWING CHART INTO YOUR NOTES:

Pyramids ReviewENERGY NUMBER BIOMASS

ENERGYSHOWS AMOUNT OF ENERGY AVAILABLE AT EACH LEVEL

ONLY 10% OF ENERGY MOVES TO NEXT LEVEL

FEWER ORGANISMS AT EACH LEVEL

ALWAYS A PYRAMID SHAPE

NUMBERSHOWS # OF ORGANISMS AVAILABLE FOR ENERGY

TOTAL # OF PRODUCERS GIVES TOTAL ENERGY AVAILABLE

SHOWS HOW ONE POP CAN AFFECT ANOTHERNOT ALWAYS A PYRAMID SHAPE

BIOMASSSHOWS MASS (BIOMASS) AVAILABLE AT EACH LEVEL

BIOMASS DECREASES AT EACH LEVELMASS MAY BE WRONG – A BIRDS BONES ARE INCLUDED, BUT NOT AVAILABE FOR ENERGY

NOT ALWAYS A PYRAMID SHAPE

ENERGY PYRAMID

NUMBER PYRAMID

25,000

1,000

50

1

NUMBER PYRAMID

5,000 Caterpillars

20 Birds

2 Hawks

1 Oak Tree

BIOMASS PYRAMID