SL Biology - Topic 4: Ecology

species

a group of organisms that can interbreed to produce fertile offspring

population

a group of organisms of the same species living in an area at one time

genetic drift

the random changes in allele frequencies in a population due to chance

autotrophs

organisms that synthesize, or produce, their own organic molecules from simple inorganic substances in it’s environment

heterotrophs

organisms which gain their organic molecules by ingesting the tissues of other organisms.

consumers

gain their organic molecules by ingesting the tissues of other living or recently dead organisms

detrivores

gain organic molecules by ingesting the tissues of dead organisms or ingesting animal waste carrying out internal digestion

saprotrophs

gain organic molecules by ingesting the tissues of dead organisms and waste material, but they secrete enzymes onto their food and digest it externally

community

multiple populations of different species living and interacting in the same area.

ecosystem

a community and its interactions with the non-living parts if it’s environment

decomposition

the process of breaking down the bodies of dead organisms and the waste products of organisms

peat

compacted partially decomposed plant matter over long amounts of time

fossilization

the process when animals and plants die in acidic or anaerobic conditions and complete decomposition cannot take place