Population Ecology Flashcards
population ecology
The study of how and why the number of individuals in a population changes over time.
Factors responsible for number of individuals in a population?
birth, death, immigration, emmigration
demography
The study of factors that determine the size and structure of populations through time.
generation
The average time between a mother’s first offspring and her daughter’s first offspring.
life table
A data set that summarizes the probability that an individual in a certain population will survive and reproduce in any given year over the course of its lifetime.
survivorship
On average, the proportion of offspring that survive to a particular age.
cohort
A group of individuals that are the same age and can be followed through time.
survivorship curve
The number of offspring each female must produce over her entire life to “replace” herself and her mate, resulting in zero population growth. The actual number is slightly more than 2 because some offspring die before reproducing.
type I survivorship curve
survivorship throughout life is high, most individuals approach the species maximum lifespan
type II survivorship curve
species have same probability of dying each year of life
type III survivorship curve
Extremely high rates of death for seeds and seedlings but high survival rates later in life
fecundity
The average number of female offspring produced by a single female in the course of her lifetime.
net reproductive rate
The growth rate of a population per generation; equivalent to the average number of female offspring that each female produces over her lifetime.
intrinsic rate of increase
The rate at which a population will grow under optimal conditions (i.e., when birthrates are as high as possible and death rates are as low as possible)
exponential population growth
The accelerating increase in the size of a population that occurs when the growth rate is constant and density independent.
