National 5 – Life on Earth – Energy in an Ecosystem
Match the following terms with their description:
Nitrogen, pyramid of numbers, biomass, decomposer, pyramid of biomass,
denitrifying bacteria, nitrogen fixing bacteria, nitrifying bacteria, competition,
interspecific competition, intraspecific competition, legumes.
Total mass of living matter
Occurs when organisms have a need for
the same resources
Organism that obtains energy by breaking
down dead organisms or waste materials
Shows the mass of organisms at each
feeding level in a food chain
Shows the number of organisms at each
feeding level in a food chain
Bacteria change nitrate in the soil back
into nitrogen gas in the air
Bacteria that break down ammonium to
nitrite, and then to nitrate
Bacteria that convert nitrogen gas in the
air into nitrates in the soil, which plants
can absorb
Element needed to make amino acids,
proteins, DNA and RNA
Competition that exists between
organisms of different species
Competition occurs between organisms of
the same species
Plant which contain Nitrogen-fixing
bacteria
Life On Earth
National 5
Dunbar Grammar School