BIOL 101 Chapter 17 & 18: Population and Community Ecology

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

dynamic and detremined by immigration and emigration

dispersion

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

what are the type of dispersion

clumped, uniform or random

clumped dispersion

individuals aggregate in areas of high resource abundance or favorable physical conditions

unifrom dispersion

individuals are evenly spaced. anaimals exhibit territoriality

random dispersion

unpredited spacing. the position of each individuals is independent of other individuals

abcesne of strong attractions or repulsions

what enviornmental factors stop a population from growing indefinatly

Environmental factors like resource scarcity (food, water, space, shelter), predation, disease, competition, waste buildup, and natural disasters (floods, fires) limit population growth by imposing constraints, ultimately leading to a stable size called the carrying capacity

why are some populations fairly stable in size while others are not

stable populations often hit carrying capacity with consistent resources

what is a birth rate that does not change with population density

density independent

what is a populations death rate increases or a birth rate decreases with increasing density

density dependent

what causes density dependednt regulation

competition for resouces

predation

disease intrinsic factors

territoriality

toxic wastes

competition for resources

increasing populations will compete for resources and reduces birth rates

disease

if it is trasnmitted by density of population then the rate increases as populatiosns become more crowded

territoriality

space becomes limited for individuals who cometes

intrinsic factors

physiological factors. hormonal changes in animals can delay s3xual maturation and depress the immune system

toxic wastes

accumulation of toxic wastes at high population density can contribute to density dependent regulation of population size

carrying capacity

the amount a place can support without damaging the ecosystem

what are limits on population size

ecological footprintlimited by food, space,

nonrenewable resources, or waste production

community

as an interacting group of various species in a common location

community structure

affected by the number, composition and reative abundance of different species within a community

interspecific interations

competition, predation, herbivatory, parasitism, mutualism, commensalism

competition

different species use a resoucre tha limits surviala and reproduction

ecological niche

specific set of biotic and abiotic enviornmental resources it uses

resources partitioning

differentiatio of niches that enable similar spcies to coexist in a community

fundamental nich

the niche potentially occupied by that species

realized nich

the funcaental niche that is acctually occupied by that species

exploitation

any interation where one spcies benefits by feeding on individuals of the other spcies

predation

individual kills another and eats tehm

have special adaptaions that help them find and identify potential prey

aposematic coloration

bright coloring that arns predators of their toxins

cyrptic coloration

camoflauge, makes prey difficult to see in their enviornments

batesian mimicry

a palatable or harmless species mimics an unpalatable spcies

basically pretending to be harmful

herbivory

an herbivore eats plants or algae

usally dont kill the plantspar

parasitism

derives nourishment from another the host

endoparasits and exoparasites

posistive interations

at leat one species benefits and neither is harmed

mutualism

benefits both species

bees and lowers

commensalism

one species benefits but the other is niether harmed nor helpsed

species diveristy

the variety of organims it includessp

cies richness

the number of different species in the communityre

lative abundance

the porportion each species in the community

trophic structure

the feeding relationships between organims in a community

pathogens

disease causing organims have strong effects on ecological communities

pathogens can particularly virulent new habitats because new host populations lack resistance

humans trasnmit pathogens

zoonotic pathogens

transferred to humans from otehr animals