Populations and Communities Flashcards
(17 cards)
What is a Species?
A group of organisms which can interbreed to produce fertile offspring
What is a population?
Organisms in the same species, in the same place at the same time
What are examples of geographical barriers?
Mountains or water
How can populations vary in size?
There are very large variables, they can vary from few to billions
What is a sessile organism?
An organism which does not move, they are fixed
What is a motile organism?
An organism which can move itself
What is the difference between motile and mobile?
Motile means it move itself, mobile means it can be moved (mobile phones)
What is random sampling used for?
Estimations of population size (only able to be used for sessile organisms)
How does random sampling work?
Taking random samples (wow so crazy) from multiple sample areas, counting there and estimating. This must be random and free of unconscious bias
What is quadrat sampling?
Type of random sampling where numbers of organisms are recorded in random areas. This must include a large number of replicates in order to produce a reliable estimate of population size
What is mark capture and release?
Estimation of motile populations, marking a certain portion of the population and releasing to recapture.
Formula:
Population size = M x N/R
M= # marked and captured initial
N = Total Number recaptured
R = Total number of recaptured with marks
What is a carrying capacity?
The maximum population size that can be supported by the environment based on resource availability
How does the fluctuation of resources impact an environment?
Resources are a limiting factor
Increased resources lead to increased population and competition
Decreased resources leads to death and reduction of population numbers
What are density dependent factors? Include examples
Increased effects on larger populations, such as competition, predation, infectious disease
What are density independent factors? Include examples
Would have the same effect regardless of population size, such as floods or fires
Population growth curves
