Population Ecology Flashcards
What are the 6 words for the definition of ecology as of now?
Relationships, species, interactions, environment, distribution, abundance
How is the space a population is limited to defined as?
The person conducting the study determines the geographical area or habitat type a population is limited to
What are the 4 limiting factors that determine where a population is and how abundant it is?
Abiotic tolerances, resource supplies, predation, mortality factors
What does density show about a population? Why doesn’t high density necessarily mean that is the best habitat for that species?
Reflects the carrying capacity, species are more common where there are more resources. Organisms could be migrating or moving around a lot, so where they are may not necessarily be the best habitat.
How does density change as organism size changes? Why is that relationship there?
Density decreases as organism size increases. Bigger things need more resources, so the environment can support less of them
What is distribution?
The geographical range of the organism, where they could be
What determines the distribution of an organism?
The presence or absence of suitable habitat, if it contains the range of ecological conditions needed for survival
How do generalists and specialists differ in geographic range, habitat tolerance, and local population size?
Generalists have a large geographic range, can tolerate a broad range of habitats, and a large local population size. Specialists have a restricted geographic range, a narrow range of habitat tolerance, a small local population size
Which 5 factors determine density and distribution?
Climate, tolerance, predators, resources, habitat availability
What causes a random distribution?
When the position of a species is not influenced by other species. Is determined by probability, not a biological process
What causes a uniform distribution?
Competition for resources and direct interactions establishes a minimum distance between neighbours
What causes a clumped distribution?
Individuals form groups due to clumped resources or social behaviour
What are relative counts?
Hints used to estimate the population size: pellets counts, catch per unit effort, frog calling codes
What are 5 reasons for potential bias when counting a population?
Time of day, stratification, detectability, misidentification, miscounting
What is the removal sampling method?
A sample of the population is taken and removed, then new samples are taken and they get smaller each time one is removed
What are the assumptions about the removal sampling method?
Same proportion is removed every time, every individual has an equal chance of being caught, population is closed during sampling, sampling does not affect the catchability of others
What is the mark re-capture method?
An initial sample is taken, marked, and released back into the population. A second sample is taken and uses N=MC/R to determine population size (total marked x size of second sample/ number of recaptures)
Using mark re-capture, how could the population size be overestimated or underestimated?
Can be overestimated by having immigration into the population after marked individuals are released. Can be underestimated if individuals that were already captured like being captured
What is dispersal?
Movement of an organism away from birthplace/ high density areas
How do organisms disperse?
Passive by gravity, wind, water and hitching a ride on animals. Active by using animals and by active movement
What would be the advantages and disadvantages to staying in the natal population?
Advantages: safety in numbers, avoid unknown conditions, know what works, familiar landscape, avoid dying while dispersing. Disadvantages: environmental variability, competition for resources, inbreeding, lower reproductive potential
Which organisms are more likely to disperse and which ones are more likely to go farther away?
Juveniles and carnivores usually leave. Bigger organisms go farther
What is a metapopulation?
A group of subpopulations that all live on separate patches that are connected by immigration and emigration among the patches.
What 4 conditions must be present for a population to be a metapopulation?
Suitable habitat occurs in discrete patches, all populations have a risk of extinction, patches aren’t too isolated, dynamics of each subpopulation aren’t synchronized
