Population Ecology notes

Population Size (N)

Population Size (N)

The number of individuals of the same species living in the same geographical area.

Population Density

The number of individuals per unit area or volume, indicating how crowded a population is.

Population Distribution

The pattern of dispersal of individuals within a population, which can be clumped, uniform, or random.

Life Table

A table that provides the probability of survival at birth for individuals of a specific cohort at various ages.

Survivorship

The probability of an individual surviving to a certain age, categorized into three types:Type I, Type II, and Type III.

Per Capita Rate of Increase (r)

The average contribution of each individual to population growth, determined by birth rate (B.R) and death rate (D.R).

Exponential Growth Model

A model where the number of individuals added each generation increases as the total number of individuals increases, represented by a "J" curve.

Logistic Growth

Population growth that slows due to environmental resistance, represented by an "S" shaped curve.

Carrying Capacity (K)

The maximum population size that the environment can support.

Density-Dependent Factors

Biotic factors that affect population size more significantly as density increases, such as competition and predation.

Density-Independent Factors

Abiotic factors that affect population size regardless of density, such as severe weather and natural disasters.

Semelparity

A reproductive strategy where individuals reproduce once per year and then die, typically producing many offspring with high infant mortality.

Iteroparity

A reproductive strategy characterized by repeated reproduction over time, producing fewer offspring with more parental care.

Demographic Transition

The shift from high death rates and birth rates to low death rates and birth rates, often influenced by factors like female education.

Age Distribution

A demographic tool used to predict future population growth based on the age structure of a population.