16 populations and ecosystems

ecology

the study of interactions between organisms and their environment

ecosystem

a community of organisms interacting with each other and the abiotic environment

habitat

where a organism lives

population

all the organisms of one species living in the same areat at the same time

niche

the role of an organism in an ecosystem, inc how it uses resources and interacts with other organisms

difference between biotic and abiotic

biotic: living factors (predation, competition)

abiotic: non living factors (temp, ph)

when does population increase in size?

birhts and immigration > deaths and emigration

immigration and emigration

immi: movement into a population

emi: movement out of a pop

describe lag phase

slow pop growth while organisms adapt to the env and prepare for reproduction

descripe exponential (log) phase

rapid pop growth because resources are abundant and reproduction rates is high

describe stationary phase

BR = DR so pop size remains stable around carrying capacity

what is carrying capacity?

the max pop size an env can support sustainably

what is environmental resistance

factors limiting pop growth, such as competition, lack of food, disease and predation

difference between density dependent and density independent factors?

DD: effect increases as population density increases (biotic factors - competition, disease)

DI: affect population regardless of size (abiotic - fire flood drought)

abundance

number of individuals in a species in a given area or volume

ecosystem

characteristic community of interdependent species interacting abiotic habitats

types to measure abundance

caputure recapture, lincoln index (plant species; % cover, % frequency, using quadrat m2)

distribution

of a species, describes the area or volume in which its found

measured by line transect : intervals

what does belt transect show, what may it be taken for?

shows abundance data for a given area at measured distance along a transect.

be taken for:

• density of species chosen

• % frequency of chosen species

• % area cover for all species

transect line laid across habitat, then quadrats are placed at regular intervals

what transect is best for systematic and sampling?

systematic: line transect, uses single line

sampling: belt, uses quadrats along a transect line

• a transect is suitable for assessing plants. but not for moving animals as they move

intra-specific competition

competition between organisms of same species

inter specific competition:

competition between organism of different species