Ecological Pyramids Flashcards
In pyramids of number, what are the lengths of the bars proportional to?
The number of organisms present at each Trophic level
What do ecological pyramids represent?
The number, mass or amount of energy stored by organisms at each Trophic level
Identify 2 drawbacks of number pyramids to describe a food chain
No account is taken of the size of the organisms and the number of individuals can be so great that it is impossible to represent them accurately on the same scale as other species in the food chain
What is a pyramid of biomass?
A quantitative description of the total mass of the plants and/or animals in a particular place within a food chain
What can make a measure of biomass unreliable
The presence of water
What is the problem with taking a dry mass measurement?
The organisms must be killed which means it can usually only be made on a small sample which may not be representative
What is a common problem between biomass and number pyramids?
Only the organisms present at a particular time are shown, seasonal differences are not apparent
What is the most accurate representation of energy transfer through a food chain?
Pyramids of energy
What must be known in order to construct an energy pyramid?
The energy stored in an organism
What is a problem with collecting the data for pyramids of energy?
It can be difficult and complex
Why are energy pyramids more representative than biomass and number pyramids?
Data are collected in a given area for a set set period of time which is usually a year
Why are the results more reliable than those for biomass?
Two organisms of the same dry masses may store different amounts of energy
