Ch 53 Population Ecology Flashcards
3 key characteristics of a population
Density
Age structure
Overall size
Density
Number of individuals in an area or volume
Arrangement
Dispersion
Types of dispersion
- Clumped (Aggregated)
- Uniform (i.e. penguins) - not random
- Random
Population size results from…
Forces that add/subtract individuals
Population size additions
Births for animals
Seed production for plants
Immigration
Population size subtractions
Deaths
Emigration
How do we measure dynamic processes?
Sample vs census
Mark recapture
Capturing a number of animals, marking them, releasing them back into the population, and then determining the ratio of marked to unmarked animals in the population
Demography (5 steps)
- Create a life table
- Follow a cohort
- Express summaries as proportion
- Create a survivorship curve
- Reproductive table
Population dynamics & demography can vary with life history traits such as (4 things):
- Reproduction age
- Number of reproductive episodes
- Number of offspring per cycle
- Reproductive tradeoffs depending on environmental conditions
Single reproductive episode might occur in
Undependable environment
Multiple reproductive episodes might occur in
Dependable environment
Population
group of individuals of a single species living in
same area & interacting
Population estimate equation
(First capture x Second capture)/Recaptured
Cohort
a group of animals of the same species
Examples of reproductive tradeoffs depending on environmental conditions (4 things)
- Predictability of rainfall
- Predictability of food
- Likelihood of right soil/light conditions
- Risk of predation
Calc equation to to represent pop growth rate at instant in time
dN/dt = rN N = population size t = time r = per capita rate of increase
per capita rate of population increase =
growth rate x pop size
logistic model includes:
carrying capacity (K)
formula to calculate how much of resource remains
(K-N)/K
Logistic growth yields:
an S-shaped curve
Regulation of populations (6 things)
- Resource competition
- Disease
- Predation
- Territoriality
- Intrinsic factors
- Toxic waste
metapopulation
number of local populations are linked
An individual’s ability to move between populations
depends on a number of factors, including ______
Genetic makeup