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APES: Populations Flashcards

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14700934924PopulationGroup of individuals of the same species living in a particular area.0
14700934925Fundamental characteristics of a populationSize, density, age/sex distribution, dispersion.1
14700934926Types of dispersionRandom (dandelions), clumping (elephant herd), uniform (penguins).2
14700934927Population changeFour variables dictate changes in the size of a population.3
14700934928Additions to a populationBirths and immigration.4
14700934929Subtractions to a populationDeaths and emigration.5
14700934930Mathematical model of population changeN1 = N + (Births + Immigrants) - (Death + Emigrants)6
14700934931Environmental factors that influence population changeFood availability, space availability, predation/disease, # of mates, competition, environmental disasters.7
14700934932Population growthWhen no environmental constraints exist, a population is able to grow at its maximum capacity.8
14700934933Biotic potentialMaximum capacity for growth in a population. Maximum reproductive rate of an organism. If given unlimited resources, how quickly could a population possibly grow.9
14700934934Intrinsic rate of increaseRate of growth given unlimited resources.10
14700934935How is rate of increase determined?Birth rate - % of new births in a year (b). Death rate = % of deaths in a year (d). Intrinsic rate - r = b - d11
14700934936Exponential growthUnrestrained growth with a constant rate of increase (J curve). Growth at a constant rate of increase per unit time. Number of individuals added to a population at the beginning of exponential growth is relatively small. But numbers increase quickly as the population, and thus the given percentage of that population, grows.12
14700934937Exponential growth equationdN/dt = rN r - intrinsic growth rate N - the initial population size dN/dt - amount of change in the population size per unit time.13
14700934938Mathematic model to calculate the size of a population over a length of timeN1 = N0e^rt14
14700934939Doubling timeA useful concept in population studies that gives perspective in terms of how easy a population is actually growing. Useful measure to illustrate speed and magnitude of growth.15
14700934940Doubling time equation70/(growth rate in percent)16
14700934941MalthusAn English economist and demographer; all biological populations have a potential for increase that exceeds the actual rate of increase, and the resources for the support of increase are limited. Recognized the potential for growth in all organisms and inspired Darwin to use this concept to explain change in populations over time.17
14700934942Environmental resistanceAll the factors that act to limit population growth. Any environmental factor that reduces population growth.18
14700934943Carrying capacity (K)Number of individuals of a given species that can be sustained indefinitely in a particular area. There is a limit to the number of individuals that can be supported. The maximum population of a given species that a particular habitat can sustain indefinitely without degrading the habitat.19
14700934944Logistic growthExponential growth with a steady decrease in the rate of population growth over time as a the population encounters environmental resistance or approaches the carrying capacity (S curve). Growth rates regulated by internal and external factors until they come into equilibrium with environmental resources. Growth rate slows as population approaches carrying capacity.20
14700934945Logistic growth equationdN/dt = rN (1 - N/K)21
14700934946When additions are greater than subtractions, the population _____________.Increases.22
14700934947When subtractions are greater than additions, the population _____________.Decreases.23
14700934948When addition equal subtractions, the population is _______.Stable.24
14700934949When resources are abundant, births tend to be ______ and deaths ____. Population tends to grow ________.High, low, rapidly. Exponential growth.25
14700934950When resources become scarce, births tend to go down and/or deaths tend to increase, population growth more ______, it _________, or ________.Slowly, stabilizes, declines. Logistic growth.26
14700934951NatalityProduction of new individuals.27
14700934952FecundityPhysical ability to reproduce.28
14700934953FertilityMeasure of actual number of offspring produced.29
14700934954ImmigrationOrganisms introduced into a new ecosystem.30
14700934955MortalityDeath rate.31
14700934956SurvivorshipPercentage of cohort (common age group) surviving to a certain age.32
14700934957Life expectancyProbable number of years of survival for an individual of a given age.33
14700934958Life spanLongest period of life reached by a given type of organism.34
14700934959EmigrationMovement of individuals out of a population.35
14700934960Arithmetic growthGrowth at a constant amount per unit time.36
14700934961Population oscillationsThe population goes up and down.37
14700934962OvershootMeasure of extent which population exceeds carrying capacity of its environment.38
14700934963DiebackNegative growth curve. Severity generally related to the extent of overshoot.39
14700934964Over time species may increase their capacity by developing ________.Adaptations. Humans may develop technologies.40
14700934965Some species maintain their capacity by ________________.Migrating to other areas.41
14700934966What has extended the earth's carrying capacity for humans?Technological, social, and other cultural advantages.42
14700934967Population densityThe number of individuals in a population found in a particular area or volume. Affect how rapidly it can grow or decline (ex: biotic factors like disease, abiotic factors like weather).43
14700934968Uniform distributionOften reflects intense infraspecific competition44
14700934969Intrinsic factorsOperate within or between individual organisms in the same species.45
14700934970Extrinsic factorsImposed from outside the population.46
14700934971Biotic factorsCaused by living organisms.47
14700934972Abiotic factorsCaused by non-living environmental components.48
14700934973Density dependent factorsHigher proportion of population is affected as population density increases. Tend to reduce population size by decreasing natality and/or increasing mortality as population size increases. Interspecific interactions - predator prey oscillations. Infraspecific interactions - territoriality, stress-related diseases.49
14700934974Density independent factorsConstant proportion of the population is affected regardless of population density. Tend to be abiotic components. Do not directly regulate population size. Natural disasters, fires, hurricanes, earthquakes, meteors, likelihood of death has nothing to do with population size.50
14700934975Stable population changeFluctuates slightly above and below carrying capacity as a population levels off.51
14700934976Irruptive population changePopulations explode and then crash to a more stable level. Members of populations which exceed their resources will die unless they adapt or move to an area with more resources. Malthusian growth - population explosions followed by population crashes. Malthus concluded human populations send to grow until they exhaust their resources and then crash.52
14700934977Cyclic population changePopulations fluctuate and regular cyclic or boom-and-bust cycles. Population sizes often vary in regular cycles when the predator and prey populations are controlled by the scarcity of resources.53
14700934978Irregular population changeErratic changes in possibly due to chaos or drastic change.54
14700934979Reproductive patterns: opturnists and competitorsLarge number of smaller offspring with little parental care (r-selected species). Fewer, larger offspring with higher invested parental care (K-selected species).55
14700934980r-Selected Malthusian strategiesShort life, rapid growth, early maturity, many small offspring, little parental care, little investment in individual offspring, adapted to unstable environment, pioneers, colonizers, niche generalists, prey, regulated mainly by extrinsic factors, low trophic level.56
14700934981K-selected logistic strategiesLong life, slower growth, late maturity, fewer large offspring, high parental care and protection, high investment in individual offspring, adapted to stable environment, later stages of succession, niche specialists, predators, regulated mainly by intrinsic factors, high trophic level.57
14700934982Survivorship curveThe way to represent the age structure of a population. The populations of different species vary in how long individual members typically live. Type I - late loss population live to an old age. Type II - constant loss population die at all age. Type III - most members of early loss population, die at young ages.58
14700934983Survivorship curve patternsFull physiological life span, probability of death unrelated to age, mortality peaks both early and late in life, mortality peaks early in life.59

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