Population Ecology Flashcards
(29 cards)
Density
number of individuals per unit area/volume
Density is the result of an interplay between processes that ____ & ______ individuals
Add and Remove
Immigration
Influx of new individuals from other areas
Emigration
movement of individuals out of a population
Dispersion
pattern of spacing among individuals within the boundaries of the population
Types of dispersion
- Clumped dispersion
- Uniform dispersion
- Random dispersion
Clumped dispersion
individuals aggregate in patches (ex. fungi, plants, salamanders)
Uniform dispersion
Individuals are evenly distributed
Random dispersion
the position of each individual is independent of other individuals (ex. dandelions, other plants with wind/water dispersed seeds)
Methods of determining population size
- Count indicator via nests, burrows, tracks, etc
- Sampling techniques to estimate densities
- Mark and recapture
Mark and recapture
The capture of a small number of individuals, put a harmless mark on them, and releasing them back into the population to determine the ratio of marked to unmarked.
Life history
comprises the traits that affect its schedule of reproduction and survival
Life history includes…
- The age at which reproduction begins
- How many offspring are produced during each reproductive cycle
Life history traits are products of …
natural selection
Demography
study of the vital statistics of a population and how they change over time, including death and birth rates
Life table
an age specific summary of the survival pattern of a population, best made by following the fate of a cohort
Cohort
a group of individuals of the same age
Survivorship curve
a graphic way of representing the data in a life table, with three distinct types
Type I Survivorship Curve
low death rates during early and middle life, then an increase among older age groupsT
Type I Survivorship Curve are associated with …
higher parental care
Type II Survivorship Curve
the death rate is constant over the organisms right
Type III Survivorship Curve
high death rates for the young, then a slower death rate for the survivors
Exponential population growth
population increase under idealized conditions; results in a J-shaped curve
Carrying capacity
“k”; maximum population size the environment can support
