Ecology Lecture 1 Flashcards
Define: POPULATION
a collection of individuals of a SINGLE SPECIES within a DEFINED AREA at a SPECIFIED point in TIME
How do populations grow with NO limiting factors?
populations are dynamic.
will experience EXPONENTIAL (or geometric) growth. It is constantly doubling.
Define: DOUBLING TIME
the DURATION it takes for a population to GROW in size, reflecting the RATE that individuals REPRODUCE.
Will exponential growth continue indefinently?
no, there is a SATURATION point.
Define: LOGISTIC GROWTH
a population grows at a DECREASING RATE, as it has reached its CARRYING CAPACITY.
Define: CARRYING CAPACITY
the MAXIMUM population size of a given species that can be SUPPORTED by a particular environment over a sustained time period.
What factors affect carrying capacity?
RESOURCES available (food, water, habitat, etc)
Define: DENSITY DEPENDENCE
the growth, mortality, or other VITAL rates of.a population are influenced by that population’s DENSITY or SIZE.
What factors limit population growth?
BIOTIC factors (ex. limited resources, predation, disease)
What is the shape of a population growth graph?
An elongated “S.”
Exponential part at beginning, saturation due to carrying capacity at the end.
Define: Density INDEPENDENT factors
abiotic factors which limit/impact population growth REGARDLESS of its size or density. (ex. extreme weather, natural disasters, climate change)
When do population declines occur?
DEATH and EMIGRATION exceed birth and immigration.
