Chapter 53: Introduction to Population Ecology

Organism

A single member of a species.

Population

A group of organisms of the same species.

Community

Multiple organisms living together.

Clumped Dispersion

Occurs when resources are not evenly distributed.

Uniform Dispersion

Occurs when individuals spread into territories due to scarce resources.

Random Dispersion

Positions of individuals do not correlate with one another.

Natality (B)

The birth rate or how much an individual adds to the population.

Mortality (D)

The death rate or how much a population loses to death.

Immigration (i)

Individuals entering a population.

Emigration (e)

Individuals leaving a population.

Growth Rate (r)

The change in population size calculated as r = (B - D) + (i - e).

Density Dependent Factors

Factors that regulate population sizes and have a greater impact as population size increases.

Density Independent Factors

Factors that limit population size regardless of population size, usually abiotic.

Semelparous

Species that reproduce once and then die, e.g., Salmon.

Iteroparous

Species that reproduce multiple times before death, e.g., Humans.

Fecundity

The potential capacity of an individual to produce offspring.

Fitness

The ability of an individual to pass on genetic information through successful reproduction.

R-Selected Species

Species characterized by high birth rates, many offspring, and little parental care.

K-Selected Species

Species characterized by low birth rates, fewer offspring, and high parental care.

Population Power vs Subistence Power

The power of population growth is indefinitely greater than the earth's ability to provide sustenance for humanity.