Population Ecology Flashcards
(26 cards)
Population
A group of the same species that life in the same general area
Density
The number of individuals per unit area or volume
Dispersion
The pattern if spacing among individuals within the boundaries of the population
Immigration
New individuals moving in from other locations
Emigration
Individuals moving out of a population into other places
Four factors that add or remove from a population
Birth rate and death rate
Immigration and emigration
Patterns of dispersion, why?
Clumped - Clumping to resources or packs
Uniform - push others away, territorial
Random - random seed dispersion like dandelions
Demography
The study of the vital statistics of a population and how they change over time
Cohort
A group of individuals born at the same time
Survivorship curve
Graph of the proportion of individuals still alive in a cohort at different ages
Exponential population growth equation
dN/dt = rN
Change in population equal births minus deaths
^N/^t = B - D
Carrying capacity (represented by what?)
Represented by K
The max population size than an environment can sustain
Logistic population growth equation
dN/dt = rN((K-N)/N)
The logistics growth model assumes…
That populations can adjust simultaneously
That the environment stays the same
Life history
Traits that affect an organisms schedule of reproduction and survival
3 main life history traits
Age when reproduction first begins
How often the individual reproduces
How many offspring are produced
“One-shot” reproduction (go big or go home)
Semelparity
Multiple opportunities to reproduce
Iteroqarity
Semelparity is favored by ..
Unpredictable environments. Get a rare chance to reproduce? Go all out.
Iteroparity is preferred by..
Stable environments where parents will likely get other chances to try a d reproduce
K-selection
Density-dependant selection
R-selection
Density-independant selection
Density independent
Birth or death factor that does not depend on density (a heat wave will kill equally)
