Ecosystems Flashcards
What is a trophic level?
a term is used to describe the position an organism occupies in a food web.
What is biomass?
a term is used to describe the total mass of living material of an organism or tissue in a given area.
What is meant by the gross production of a producer?
the total solar energy a plant converts into organic matter.
What is the net production of a producer?
the gross production minus losses due to respiration.
What is meant by the term saprophytic nutrition?
The gaining of energy from the breakdown of dead organisms or waste materials.
What is meant by the term nitrogen fixation?
The conversion of nitrogen in the atmosphere into ammonia.
Name two bacteria which carry out nitrogen fixation.
- Rhizobium
- Azotobacter
What is meant by the term nitrification?
The conversion of ammonium ions into nitrites and nitrates.
What reaction is carried out by the nitrifying bacteria of the Nitrosomonas genus?
Oxidation of ammonium ions to nitrites.
What reaction is carried out by the nitrifying bacteria of the Nitrobacter genus?
Oxidation of nitrites to nitrates.
What is meant by the term denitrification?
The conversion of nitrates to nitrogen (under anaerobic respiration).
What is primary succession?
Colonisation of barren terrain by living organisms over time.
What is secondary succession?
Recolonisation of an area after an earlier community has been removed.
What is a pioneer species?
A species that can colonise barren terrain.
What is a climax community?
A community not subject to further succession.
