BIOL 117 CH 40 - Pop Ecology and Distribution of Organisms

ecology

the scientific study of the interactions between organisms and the environment.

global ecology

examines the influence of energy and materials on organisms across the biosphere

landscape ecology

focuses on exchanges of energy, materials, and organisms among ecosystems

ecosystem ecology

emphasizes energy flow and chemical cycling among biotic and abiotic components

community ecology

deals with the whole array of interacting species in a community

population ecology

focuses on factors affecting population size over time

organismal ecology

studies how an organism meets environmental challenges

climate

influences the structure and distribution of terrestrial biomes

biomes

major life zones characterized by vegetation type (terrestrial) or physical (aquatic) environment

trade winds

blow east to west in the tropics

westerlies

blow west to east in temperature zones

watersheds

defines the boundaries of freshwater ecosystems

thermocline

separates the warm upper layer from the cold deeper water

photic zone

most organisms occur in shallow photic zone

aphonic zone

extensive but harbors little life

abiotic

non-living part of an ecosystem that shapes its environment

biotic

living components that shape the environment

abiotic factor examples

temp, water and oxygen, salinity, sunlight, rocks and soil

biotic factor examples

predation, herbivory, mutualism, parasitism, competition

population

a group of individuals of a single species living in the same general area

density

the number of individuals per unit area or volume

dispersion

a pattern of spacing among individuals within the boundaries of the population

demography

study of the vital statistics of a population and how they change over time

fecundity

number offspring potentially produced

fertility

actual # of offspring produced

survivorship curve

a graphic way or representing data in a life table

reproductive table

age-specific summary of repro rates of a pop

growth rate

how many new individuals are contributed to the population

exponential growth

growth under idealized conditions

carrying capacity (K)

the maximum population size the environment can support

logistic growth

growth rate declines as carrying capacity is reached

life history

traits affecting an organism’s schedule of reproduction and survival

density-dependent selection (k-selection)

selects for life history traits that are sensitive to population density (ex: large mammals, trees)

density-independent selection (r-selection)

selects for life history traits that maximize reproduction irrespective of how dense the population is (ex: weeds, insects, mice)

population dynamics

focus on the complex interactions between biotic and abiotic factors