populations: 8B quiz 4/28 🐈

what is a population?

organisms of the same species living in an area

what is geographic distribution?

area where individuals live

what is density?

number of individuals per unit of area

how do we calculate density?

number of individuals/the size of the area

what is the growth rate?

how the number of individuals in a population increases or decreases over time

what is population growth?

how the number of individuals changes over time

what three factors effect population size?

number of births, number of deaths, number of individuals entering or leaving the population

why would an organism immigrate/emigrate?

food or water, better living conditions, mating purposes

what are the two types of growth?

exponential and logistic

exponential growth occurs when…

resources are unlimited, no limits on growth, and reproduction is at a constant rate

exponential growth has what shape of the curve?

J-shaped curve

logistic growth occurs when…

resources become less available, the growth of the population slows down or stops, reaches it’s carrying capacity

logistic growth has what shape of the curve?

S-shaped curve

what is carrying capacity?

the maximum number of individuals that the resources can support

how can the carrying capacity change?

due to environmental changes

factors that limit the growth of populations are referred to as…

density-dependent factors and density-independent factors

what are density-dependent factors?

factors that become limiting when the density of the population reaches a certain level

what are some examples of density-dependent factors?

competition, predation, parasitism, disease

what are density-independent factors?

factors that affect all populations in the same way, regardless of population size

what are some examples of density-independent factors?

weather, natural disasters, seasonal cycles, human activities