Population Dynamics Flashcards
Population (Definition)
A group of organisms of one species that interbreed and live in the same place and time
- Characterized by size (number of individuals) and density
Distribution
- Avail. S/B. Intra. Dispers. Find.
Observing species distribution
can help determine:
- availability of resources
- social/behavioral aspects
- intraspecific interactions
- dispersal of offspring
- finding mates
Survivorship
Mortality rates and life expectancy can be calculated
Survivorship curves show number of survivors at each stage
- Type I= high mortality late in life
- Type II= mortality is constant throughout life
- Type III= high mortality early in life
Population Growth (Types)
- Exponential growth
- Logistic growth
- Growth rate
Exponential growth
- Unlimited resources
- Can be seen early, as a population is growing
- “J” curve
Logistic growth
- Resources become limited and carrying capacity is reached
- Growth plateaus
- “S” curve
Growth rate
- Slope of line
- Births vs deaths
Controls on Population
(Density-dependent & Density-independent)
Density-dependent : the density of the population affects growth rate and mortality
- Factors that depend on pop. size :
- Interspecific competition (between 2 or more species)
- Intraspecific competition (within a species)
- Predation
- Parasites
Density-independent : mortality in a population occurs regardless of population density
- Factors that affect populations similarly :
- Weather
- Natural disasters
- Pollution
Population Models
Life history traits can affect population growth
r-selected species (ex : sea turtles)
- Organisms that make many, small offspring
- Provide no/little parental care
- Live in unstable environments
K-selected species (ex : primates)
- Organisms that make larger and fewer offspring
- Provide parental care
- Live in stable, predictable environments
