Population dynamics Flashcards
Population
Population is a group of organisms of the same species living together in one geographical area.
How population can shrink
- Number of births
- Number of deaths
- Emigration (organisms moving out of the habitat)
-Immigration (organisms moving into the habitat)
Distribution and Density
As well as population size, distribution and density are two interrelated properties of populations that can be studied.
Population Density
Population density is the number of individuals per unit rates ( for land organisms) or volume (for aquatic organisms).
Example of population density
Tiger (low density)
Termites (high density)
Population Distribution
Careful observation and precise mapping can determine the distribution patterns for a species.
Three distribution patterns
Uniform, random and clumped.
Uniform Distribution
Regular, uniform distribution patterns occur when individuals are evenly spaced within the area.
Random Distribution
Random distribution occurs when spacing between individuals is irregular.
Clumped distribution
Clumped distribution occurs when individuals are grouped in patches mostly around a recourse.
Exponential growth pattern
(J curve) occurs in an ideal, unlimited environment.
Logistic growth pattern
(S curve) occurs when environment pressures slow the rate of growth.
Carrying Capacity
The carrying capacity is the maximum population size of a species that the environment can sustain indefinitely.
Population overshoot
When the new population exceeds the carrying capacity.
Population crash
When they then start to die off and the environment will start to recover.
Oscillations
After a period of time, the population may be able to grow again. The repeated cycle of overshoot and crash are called oscillations.
