Chap. 5 Populations Flashcards
Characteristics of populations
distinguishing physical variations(age,gender,ethnicity,risk of certain disease, etc)
population growth rate
the rate a pop. increase/decrease
population density
measurement of population per unit land area
death rate
ratio of deaths in a pop. of a particular area during particular period of time
Birth rate
The ratio of births in a population of a particular area or during a particular period of time
Emigration
when organism leaves an area
Immigration
when organism enters an area
Exponential growth
the bigger the pop. the faster it grows. grows infinitely with unlimited resources (j shaped curve)
Logistic growth
population grows exponentially first but slows as pop. size nears carrying capacity and becomes stable (s shaped curve)
carrying capacity
max pop. size of a biological species that can be sustained by a specific enviro from factors involved e.g. pond hold 5 abused fish. big pond hold 6 abused fish.
density dependent factors
pop. growth reduced by ltd. resources due to big pop. (disease,comp,predators)
density independent factors
pop. size affected regardless of size e.g. weather/natural disasters
age structure diagrams
diagram that shows distribution by ages of females&males within certain pop. in graphic form
