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 Review ENERGY NUMBERBIOMASS

ENERGY SHOWS AMOUNT OF ENERGY AVAILABLE AT EACH LEVEL ONLY 10% OF ENERGY MOVES TO NEXT LEVEL FEWER ORGANISMS AT EACH LEVEL ALWAYS A PYRAMID SHAPE

NUMBER SHOWS # OF ORGANISMS AVAILABLE FOR ENERGY TOTAL # OF PRODUCERS GIVES TOTAL ENERGY AVAILABLE SHOWS HOW ONE POP CAN AFFECT ANOTHER NOT ALWAYS A PYRAMID SHAPE

BIOMASS SHOWS MASS (BIOMASS) AVAILABLE AT EACH LEVEL BIOMASS DECREASES AT EACH LEVEL MASS 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,

NUMBER PYRAMID 5,000 Caterpillars 20 Birds 2 Hawks 1 Oak Tree

BIOMASS PYRAMID