Population Characteristics
The graph to the right shows the growth curve obtained from an experiment
with yeast, examining how the number of yeast cells changed over time.
1.
Describe the growth pattern of the yeast in words.
2. Explain why it is shaped this way.
The graph to the right illustrates the growth curve of a population of rabbits once they were introduced into a closed
ecosystem.
3. What does closed mean in this context?
4. What happens to the number of mice after year 3?
5. Explain the population growth pattern.
This graph shows the growth curve for the global human
population from 10000 BCE (before current era) to 2000 CE.
6. If we were to extrapolate the graph, what paths might it
take?
7. Which of these paths do you think is most likely?
Carrying Capacity:
The maximum, equilibrium number of organisms of a particular species that can be supported indefinitely in a given
environment
Law of the Minimum: The nutrient in least supply is the one that limits the growth of a population
Law of Tolerance: too much or too little of an abiotic factor can cause death. Populations will only survive if the
abiotic factors that affect them stay within certain tolerances. These tolerances are different for every species.
Biotic Potential: The maximum number of offspring a species can produce if resources were unlimited
The factors that determine it are:
1. Birth Potential: The maximum number of offspring per birth
2. Capacity for survival: The number of offspring that will reach reproductive age
3. Procreation – the number of times the organism reproduces in one year
4.
Length of the reproductive life – the amount of time from reaching sexual maturity until the organism can
no longer reproduce.
Homework:
Pick a species and find the numbers for the four factors that affect Biotic Potential