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Population Dynamics: Population Studies (Distribution patterns can change…
Population Dynamics: Population Studies
Sampling: using a group within a given population to infer traits/sizes of the entire population.
Population Density: A mathematical calculation used to infer/approximate the amount of population within a habitat/living space.
Pd = Number of individuals/area of land
Sampling techniques are used by analysts and scientists to most effectively find the population of a given species of organisms.
Mark-Recapture: sampling technique used for mainly mobile animals like birds. Organisms are caught, tagged and tracked then released, and are studied thereafter
Transects: sampling technique used for large and fairly stationary organisms like large trees. Organisms are sampled along a long, rectangular area, and counts the number of individuals. These counts are tracked and recorded
Quadrants: sampling technique used for small organisms who may travel, but stay within a certain space for most of the time like squirrels. Equal squares or rectangles from a given area are made, analysts calculate the number of organisms per square and determine the population density, their final results are based on this calculation
Population Distribution & Distribution Patterns: Where a population of organism can most likely be found dispersed on an area at a certain time. Distribution patterns study what types of distribution certain populations experience compared to other organisms.
Clumped Distribution: small colonies of organisms mainly spread equidistant from other small colonies in the same population. Can be caused by limited resources, food or shelter. ex. Meerkats
Uniform Distribution: Individual organisms are equidistant, but alone, no colonies or 'communities'. ex. Birds when mating
Random Distribution: organisms are at random distances from other organisms in the same population. Can be caused by a random spread of resources like food
Distribution patterns can change based on circumstance. Circumstances can be external or internal.
External Circumstance: a circumstance caused outside of the species, but can change the behaviour/size of the population. ex. Natural disasters, pollution
Internal Circumstance: a circumstance caused inside the population which can change the behaviour/size of the species. ex. Infertility
Life history: previous survivorship and reproductive present in a species based on previous generations of that same species.
Fecundity: Avg number of offspring produced by a female individual of the population over her lifetime. ex. Clownfish have a higher fecundity than humans
Survivorship: the fraction of a certain population which live to be a certain age.
Survivorship curves, graphically show the percent of population who live to be a certain age vs. that population's number of survivors
Type III Survivorship: high death rate immediately following birth. ex. Oyster
Type II Survivorship: equal ratio of life span and survivors ex. Songbird
Type I Survivorship: number of survivors decays exponentially (slow) and a high percent lives for a long period of time. ex. Humans
Immigration: organisms moving into the population
Emigration: organisms moving out of the population
Population Change with Immigration and Emigration: (Births + Immigration) - (Deaths + Emigration)
Change in population: Births - Deaths
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