AP Biology Chapter 53: Population Ecology – Flashcards
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What two pieces of data are needed to mathematically determine density?
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Number of organisms and area of habitat
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Density
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Number of individuals per unit area
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Dispersion
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The pattern of spacing of individuals
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Formula N=mn/x n is _____.
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Number of second sampling.
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Formula N=mn/x s is _____.
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Number released in first sampling.
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Formula N=mn/x x is _____.
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Number of marked individuals in second sampling.
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Explain the impact of immigration and emigration on population density.
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They alter the density of populations and increase gene flow between populations.
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Clumped dispersion pattern
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Animals group around food (social animals).
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Uniform dispersion pattern
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Animals are dispersed evenly with aggressive territoralism.
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Random dispersion pattern
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Organisms are randomly dispersed, just where they land.
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Cohort
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A group of individuals of the same age.
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Population statistic that demographers have a particular interest in?
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Birth and death rates (helps create a life table).
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Survivorship curve I (one)
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Most individuals live to older age. Small number of offspring. Lots of parental care.
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Survivorship curve II (two)
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Individuals live and die at consistent rate. Medium number of offspring.
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Survivorship curve III (three)
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Many individuals die during first stages of life but those that survive live long. Large number of offspring. No parenting.
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What does a reproductive table show?
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Age specific summary of reproductive rates in a population. (Measured by reproductive rates of a cohort.)
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On what is the life history of an organism based?
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The traits that affect an organism's schedule of reproduction and survival from birth to death.
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What three variables form the life history of a species?
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Age of reproduction How often an organism reproduces How many offspring per reproductive episode
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Semelparity
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Single reproductive episode before death (release eggs) can wait for right conditions, release a lot survival rate of offspring is low.
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Iteroparity
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Multiple reproductive cycles over the course of its lifetime more dependable environments.
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Two critical factors for determining if a species will evolve toward semelparity or iteroparity.
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Survival rate of offspring Likelihood that the adult will survive to reproduce again
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Explain the effect of offspring care on parental survival in kestrels.
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There appears to be a negative correlation between brood enlargements and parental survival.
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What is the advantage to using per capita birth and death rates rather than just the raw numbers of births and deaths?
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Per capita gives average of the number of offspring per individual and number of deaths per unit of time.
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What will the per capita birth and death rates be if a population is demonstrating zero population growth?
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They will be equal.
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What does it mean for a population to be in exponential population growth?
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A population that is growing without limitation of resources.
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What are two examples of conditions that might lead to exponential population growth in natural populations?
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Excess of food and water (resources) Free to reproduce as often as possible
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What is carrying capacity?
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Maximum population size that an environment can sustain.
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What are six examples of limiting resources that can influence carrying capacity?
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Space Water Food Mate availability Shelter Predator
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In the logistic population growth model, the per capita rate of increase approaches zero as the _____ _____ is reached.
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Carrying capacity
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K-selection
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Density-dependent selection, have few offspring, parent heavily
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R-selection
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Density-independent, lots of babies, no parents
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Density-independent regulation
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Provides regulation by reducing birth rate and increasing death rates (competition for food)
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Density-dependent regulation
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Regulation of population regardless of population density (lightning strikes and there is a fire)
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Explain negative feedback's role in the regulation of populations.
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It keeps the population at or near carrying capacity through affecting birth and death rates in a large (close to K) population.
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Negative feedback mechanism: Competition for resources
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Organisms compete for food and water (Mice have a limited insect supply)
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Negative feedback mechanism: Territoriality
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Organisms compete for space by fiercely defending an area (Mountain lions have large territories)
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Negative feedback mechanism: Disease
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Diseases increase death rates by killing weak organisms (Bats have fungus)
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Negative feedback mechanism: Predation
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Predators control prey population and vice versa (Number of foxes and rabbits in field fluctuate together)
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Negative feedback mechanism: Toxic wastes
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Some organisms (bacteria/yeast) make toxic wastes that kill some population (Yeast makes alcohol which builds up until death)
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Negative feedback mechanism: Intrinsic factors
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Hormonal/physiological changes in animals based on food (If women are nutrient deficient they stop menstruating)
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Importance of immigration and emigration in metapopulations.
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A metapopulation is when two or more populations are linked, it is important to have constant immigration and emigration.
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Human population growth since 1650.
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We have been exponentially growing until lately. We have slowed down. (2.2% in 1962, 1.2% in 2009)
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Demographic transition
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Movement from high birth and death rates to low (This has happened in both Mexico and Sweden since 1750)
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Afghanistan
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Large younger population (Prediction: explosive growth rate)
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United States
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Even number from 0-55 (Prediction: grow slowly)
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Italy
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Less children than adults (Prediction: no growth)
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Why do infant mortality and life expectancy vary so greatly between certain countries?
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They reflect a quality of life and parental choices.
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Can the world's population an ecological footprint that is currently the average American's footprint?
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The average American footprint is 10 and it is unsustainable at 1.7 (Over using resources!)
