Describe the limiting factors of an ecosystem

•What is an ecosystem?

•What are biotic & abiotic factors?

•What is reproductive

potential?•What is a limiting

factor?

What is a population?What is a population?• Every population has potential to Every population has potential to increase in sizeincrease in size– Some have potential for slow, steady Some have potential for slow, steady growthgrowth

– Others have potential to increase Others have potential to increase rapidlyrapidly

• If you have the proper information, If you have the proper information, you can calculate the potential for you can calculate the potential for population growth of any organismpopulation growth of any organism

ReproductivePotential

Theoretical unlimited growth of a population

over time

What information would you need in order to predict the size of the population in the

future?

Entomologists have discovered. . .

• Live for 4 months• Female mates at 2 months• Female lays 100 eggs in her

lifetime• Eggs are a ratio of 50 male:50

female

How many?Without any limitations on population growth, every egg produces a new individual in the population, and every

individual lives out its natural life every 4 months

11

5050 102 2

months

25050

25002500 5100 4

months

32 billion bugsCircle the Earth eight

times if they stood in a line, nose to tail

32 billion bugs

Have a mass equal to about Have a mass equal to about 30,000 typical middle school 30,000 typical middle school

studentsstudents

Why aren’t we overrun with milkweed bugs?

Limiting FactorsAny biotic or abiotic factors

that acts in some way to limit the number of

individuals that survive and reproduce in a population

Population Limiting Factors

StormOld ageFloodCompetitionHeatStarvation

DroughtPredationFreezingDiseaseAbioticBiotic

ReflectionReflectionChoose your favorite biotic organism and

illustrate and explain at least 3 limiting factors

to its growth