Health 2110 Population Dynamics

Population

individuals of the same species living living together

Community

Different organisms are not randomly scattered, but live in together in an orderly manner.

Ecosystem

Functional units of nature in which living organisms interact with each other and with non-living components of their environment to process energy

Examples of Ecosystems

• Cow Pasture

• Salt marsh

• City Parks

• Forests

Population Change

When populations of an organism increase greatly (swarms of locust, and tent caterpillars) something eventually brings the population back into equilibrium with the environment.

Population Dynamics

The study of ecological principles that govern the ways in which populations change in size.

Population Attributes

• Characteristics unique to a given population (birth and death rates, age structure, spatial distribution)

• Helpful for predicting how the population will respond to environmental changes.

Biotic Potential

Maximum achievable growth rate with unlimited space in the absence of limiting factors.

• Disease, predation, and food supply

Environmental Resistance

Measured difference between biotic potential of a population and the actual observed rate of growth.

What population growth “looks like”

s-curves and j-curves

Sigmoidal Curves (s-curve)

• Lag Phase: slow growth

• Exponential growth phase: dramatic growth in short period of time

• Steady-state equilibrium (or carrying capacity)