10.1 the nature of ecosystems Flashcards
what is an ecosystem?
an environment including all the living organisms interacting within it, the cycling of nutrients and the physical and chemical environment which the organisms are living
what is a trophic level?
the position of an organism in a food chain or web and describes it’s feeding relationship with other organisms
what is the general model of the food chain?
producers –> primary consumers –> secondary consumers –> tertiary consumers –> decomposers
what are the three types of pyramids used?
- pyramids of numbers
- pyramids of biomass
- pyramids of energy
how do we loose energy through food chains?
- lost in waste (faeces)
- drive respiration
what are the three types of distribution in a habitat?
- uniform
- clumped
- random
what is uniform distribution?
when resources are thinly but evenly spread
what is clumped distribution?
herds of animals or groups of plants clump in areas where resouces are found
what is random distribution?
result of plentiful resouces
what are the different ecological techniques?
- quadrats
- transects
- light traps
- mark, release and recapture
quadrats
- quantitative sampling
- individual counts or percentage cover
what are the weaknesses of using a quadrat?
- limitations to the area you can sample
- the randomnessof the sampling sites
- desicions made about wether to include or exclude organisms partly covered by the quadrat
what is the scale we can use to measure abundance in a quadrat?
ACFOR scale
what does ACFOR stand for?
A= abundant
C= common
F= frequent
O= occasional
R= rare
what are the limitations to the ACFOR scale?
- subjective
- no definitions or terms
- species can easily be rated by how obvious they are rather than how abundant they are
