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27 Cards in this Set
- Front
- Back
Define:
Populations |
A group of organisms of the same species occupying a particular place at a particular time.
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Why are populations said to be the "unit of evolution"?
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Because evolution occurs within a population.
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Define:
Abundance |
The number of organisms in a population.
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In what "unit" is abundance usually expressed as?
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Density
(# of organisms) / unit area (# of organisms) / unit volume |
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Population density:
What are the 2 main factors that INCREASE population density? |
Natality
Immigration |
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Population density:
What are the 2 main factors that DECREASE population density? |
Mortality
Emigration |
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Define:
Natality |
Addition of new individuals by reproduction
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True/False:
Different organisms require different techniques for determining their population density |
...TRUE!
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What are the 2 main forms of estimating density?
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1 - Absolute density (e.g. population has 14 individuals / km^2)
2 - Relative density (i.e. Area X has more of individual A than Area Y) |
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What are 2 techniques used to get an Absolute density?
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1 - Total count (count *every* individual in a population)
2 - Sampling methods |
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Describe a sampling method (as it relates to estimating absolute density)
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A small portion of the population is counted, and results are extrapolated to the whole.
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Define:
Quadrat |
A sampling area of any shape or size
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Describe how Quadrat sampling works
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a) Form some quadrats (an area of known size)
b) Count exact number of organisms in your quadrats c) Average density of organism in quadrat is extrapolated to the whole population |
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Quadrat sampling works well for what type of species?
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stationary species (e.g. trees, invertebrates)
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What are 3 assumptions to Quadrat sampling?
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1 - Numbers in quadrats are counted *exactly*
2 - Area of quadrats must be known *exactly* 3 - Quadrats are representative of whole area (i.e. they were placed in a random manner) |
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Describe the Peterson Index method of estimating absolute density.
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1 - Sample of M individuals are removed from a population of size N
2 - Individuals are marked and released back into the population 3 - Sample of n individuals are captured at some point in the future. 4 - Some of those captured (m) will be marked from first sample. USE: N = Mn/m |
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List the equation for the Peterson Index, and describe what each variable (4 of em) represents.
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M/N = m/n
or N = Mn/m M = # captured and marked N = estimate of population size n = Total # captured on second run m = # out of n who are marked |
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What are the 3 assumptions of the Mark-Recapture method?
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1 - Marked and unmarked captured randomly
2 - Marked and unmarked have same mortality (i.e. bunnies are not marked by dipping in orange paint) 3 - Marks are not lost or overlooked |
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What are 4 ways to estimate Relative Density?
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1 - Captures / unit effort
2 - Scats and fecal pellets 3 - Vocalization frequency 4 - Artifacts |
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Define:
Fecundity |
Fecundity ≡ Potential reproductive output
EXA: Human fecundity = 1 child / 10-11 months |
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Define:
Fertility |
Fertility ≡ Actual reproductive output
EXA: Human fertility = 1 child / 15 years |
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Define:
Potential longevity |
Maximum lifespan
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Define
Actual longevity |
Mean lifespan
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TRUE or FALSE:
Over the course of history, actual human longevity has remained constant while potential human longevity has steadily increased. |
FALSE
Potential human longevity has remained constant at around 100 years of age. Actual human longevity has steadily increased due to advances in hygiene, medicine, etc. |
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Define:
Source Population |
Emigration > Immigration
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Define
Sink Population |
Immigration > Emigration
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What are 3 ways that populations are not composed of identical individuals?
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1 - Individuals differ by genotype
2 - Individuals differ by sex 3 - Individuals differ by age |