Population Ecology Flashcards
What are the 2 modes of population growth?
J growth curve (exponential curve)
S growth curve (logistic curve)
What can J growth curve be used as?
describes population growth in an idealized, unlimited environment
idealized situations help us understand the capacity of species to increase and the conditions that may facilitate this growth
change in population size is equal to….
births + immigrants entering population - deaths - emmigrants leaving population
Population growth rate can be expressed as….
N (b-m)
where b is the annual per capita birth rate, m (for mortality) is the per capita death rate, and N is population size
What is zero population growth
when the birth rate equals to the death rate
Equation of exponential population growth
dN/dt = rmax x N
What are the 2 phases in J growth curve
Lag Phase - slow because the population is small
Exponential Growth - growth is accelerating
What can S growth curve be used as?
describes how a population grows more slowly as it nears its carrying capacity
What is Carrying Capacity?
maximum population size the enviroment can support
Equation of logistic population growth
dN/dt = rmax x N x (K-N)/K
3 types of survivorship curve
Type I - low death during early life, higher death rate for survivors
Type II - constant death rate among any age group
Type III - high death during early life, lower death rate for survivors
What are the traits that affect organism’s schedule for reproduction & survival?
Age at which reproduction begins
How often the organism reproduces
How many offspring are produced during each reproductive cycle
2 types of life history traits
K-selection @ density-dependent selection - sensitive to population density
r-selection @ density-independent selection - maximize reproduction
Lifespan of r-selection organism vs K-selection organism
r-selection organism usually has short life span
K-selection organism usually has long life span
Population size of r-selection vs K-selection
Population size of r-selection is variable and below carrying capacity
Population size of K-selection is constant and at carrying capacity
