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19 Cards in this Set
- Front
- Back
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3 patterns of dispersion. which one is the most common?
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clumped, uniform, random// clumped
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what are 2 things that contribute to variation in population density?
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environmental differences and social interaxns.
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what are 3 demographic factors that influence both population densiy and dispersion?
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ecological needs of a species, structure of the environment, and interactions bt/w individuals.
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what is a population?
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group of individuals of a single species living in the same general area.
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what is a cohort?
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group of individuals of the same age, usually studied from birth until death for a life table.
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what is a survivorship curve?
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a plot of the proportion or numbers in a cohort still alive at each age.
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what is the difference bt/w semelparity and iteroparity?
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semelparity = organism gets one shot at reproducing
iteroparity= organism has repeated reproductive acts; i.e., every year. |
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when is semelparity favored?
iteroparity? |
1. when survival rate of offspring is low
2. in dependable environments where competition for resources is high. |
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what is the formula for the Total Population in the mark & recapture method of sampling
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# individuals captured in first set of traps X the # individuals in 2nd set of traps / the total number of individuals tagged
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T or F. trade-offs must be made by organisms for reproduction and survival
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True
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what is K, the carrying capacity?
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the max # of individuals who can be sustained in a given environment.
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What is the exponential growth model assumption?
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that resources are unlimited
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what is k-selection?
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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. |
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what is R-Selection?
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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
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name 6 density dependent mechanisms that cause birth and death rates to change.
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competition for resources
health toxic wastes predation intrinsic factors territoriality |
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identify 3 characteristics of population size for each the R-selected species and the K-selected species.
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K-selected: limited by carrying capacity
density dependent relatively stable R-selected species: limited by r, reproductive rate density independent relatively unstable |
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Identify 3 characteristics of organisms in each k-seleced and r-selected species.
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K-selections
larger, long-lived produce fewer offspring produce greater care for offspring r-selected: smaller, short lived produce many offspring produce less care for young |
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what is age-structure?
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the relative # of individuals of each age.
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what is evolution/ microevolution?
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the genetic makeup of a population from generation to generation.
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