Population growth Flashcards
What does reproduction result in?
population growth
What is a population defined as?
All individuals of a given species that reproduce in a particular place
What is population size?
The number of individuals alive at a particular time in a particular place and is influenced by birth, death, immigration, and emigration
What is a graph like under ideal conditions?
An exponential model. Rmax (intrinsic rate of increase) is constant and positive; also varies by species
What limits population growth?
Temperature, precipitation, predators, disease, food availability
What is carrying capacity (K)?
Most environments can only support a certain population size. Factors that limit population growth combine to determine the carrying capacity. As population reaches carrying capacity, growth of population will decrease
What is the logistic model of population growth?
As populations grow; death rates increase and birth rates decrease. r decreases as N carries towards K
What density dependant (biotic) factors influence population growth?
- Food availability
- Shelter
- Mates
- Predation
- Disease
What density independant factors (abiotic) influence population growth?
- Temperature
- Precipitation
- Light
- Disturbances (hurricanes, landslides, fires)
What life history strategies influence r selected species?
- Live in environments with disturbance
- Go through boom cycles of population growth/collapse
- Individually smaller in size
- Early mating
- Stay near the bottom of the curve
What life history strategies influence k selected species?
- Have populations close to carrying capacity
- Stronger competitors
- Individually larger in size
- Long lived
- Survive extremes
- Live with less disturbances
