BS 110 Quiz 5
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- What is a population?
- A group of organisms of the same species that occupy a particular space and the same time
- What are the 4 ways of describing a population?
- density, dispersion, demography, and dynamics
- What is population density?
- the number of individuals per area
- What are the two approaches used when measuring the density of a population?
- census and sample
- How is the census approach used?
- By counting every individual
- What are some problems with census counting?
- The organisms must be easy to observe, not too numerous, and occur in an easily defined area
- How is sampling done to measure density?
- you must observe a small area and mark and organisms in area and do calculations to extrapolate to the population size
- When is sampling used?
- When the population is too large or too spread out
- What are the two methods used when sampling is conducted?
- transects and capture, mark, and recapture
- What is an transect?
- Pre-determined points along specific lengths through a site where mathematical models are used to extrapolate population sizes
- What is done with the capture and release approach?
- Organisms are captured and marked and based on how many the researcher finds they extrapolate a population size
- What is dispersion?
- A way of describing populations that occur in space and time
- What are the two patterns of dispersion?
- spatial and temporal
- What are the three patterns in spatial dispersion?
- uniform, clumped, and random
- What is uniform dispersion?
- When the spacing of individuals are more evenly spaced than they would occur by chance
- Why would you see uniform dispersion?
- If the organisms where highly territorial or if there was limited resources
- What is clumped dispersion?
- The spacing of the individuals is clustered and is the most common form of dispersion
- Why would you see clumped dispersion?
- If there was habitat differences among organisms, environmental fluctuations, reproductive patterns, and social behavior
- What is random dispersion?
- When the distribution of individuals are random and this is the rarest form of dispersion
- Why would you see random dispersion?
- if there was an absence of factors that would drive other distributions like if strong attractions and repulsions are missing or if resources are uniformly available
- What is temporal dispersion?
- when organisms migrate to new areas throughout the seasons
- What is demography?
- The factors that determine population size and structure over time
- What causes the population to increase?
- births and immigration
- What causes the population to decrease?
- deaths and emigration
- The factors that cause the population to grow and shrink influence what?
- the density and dispersion of the population
- What selected species would have high fertility, rapid growth, early sexual maturity, lots of offspring, and low investment in those offspring?
- R-selected species
- What selected species would have low fertility, slow growth, later stages of sexual maturity, few offspring and high investment in those offsprings
- K-selected species
- What are dynamics?
- How population sizes change over time
- When does zero population growth occur?
- When the birth rate equals the death rate
- What does the exponential growth model describe?
- The population growth in an idealized, unlimited environment
- What does a logistic growth model describe?
- How a population grows more slowly as it approaches its carrying capacity
- What does carrying capacity mean?
- The ability of the environment to support a population size