Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

19 Cards in this Set

  • Front
  • Back
3 patterns of dispersion. which one is the most common?
clumped, uniform, random// clumped
what are 2 things that contribute to variation in population density?
environmental differences and social interaxns.
what are 3 demographic factors that influence both population densiy and dispersion?
ecological needs of a species, structure of the environment, and interactions bt/w individuals.
what is a population?
group of individuals of a single species living in the same general area.
what is a cohort?
group of individuals of the same age, usually studied from birth until death for a life table.
what is a survivorship curve?
a plot of the proportion or numbers in a cohort still alive at each age.
what is the difference bt/w semelparity and iteroparity?
semelparity = organism gets one shot at reproducing

iteroparity= organism has repeated reproductive acts; i.e., every year.
when is semelparity favored?
1. when survival rate of offspring is low
2. in dependable environments where competition for resources is high.
what is the formula for the Total Population in the mark & recapture method of sampling
# individuals captured in first set of traps X the # individuals in 2nd set of traps / the total number of individuals tagged
T or F. trade-offs must be made by organisms for reproduction and survival
what is K, the carrying capacity?
the max # of individuals who can be sustained in a given environment.
What is the exponential growth model assumption?
that resources are unlimited
what is k-selection?
selection for life history traits that are sensitive to population density// density dependent selection.

it maximizes population size and operates in pops living at a density near the carrying capacity, K.
what is R-Selection?
density independent selection. it tends to maximize the rate of increase, r, and occurs in environments where pop densities fluctuate well below carrying capacity or there is little competition
name 6 density dependent mechanisms that cause birth and death rates to change.
competition for resources
toxic wastes
intrinsic factors
identify 3 characteristics of population size for each the R-selected species and the K-selected species.
K-selected: limited by carrying capacity
density dependent
relatively stable

R-selected species:
limited by r, reproductive rate
density independent
relatively unstable
Identify 3 characteristics of organisms in each k-seleced and r-selected species.
larger, long-lived
produce fewer offspring
produce greater care for offspring

smaller, short lived
produce many offspring
produce less care for young
what is age-structure?
the relative # of individuals of each age.
what is evolution/ microevolution?
the genetic makeup of a population from generation to generation.