4.1 The organisms in the environment - STILL NEEDS SORTING Flashcards
what is ecology?
the study of ecosystems
what is an ecosystem?
An ecosystem is an easily described system or area where organisms interact with their physical environment.
what is a population?
the total number of individuals of one species in a particular habitat at a particular time
what is a community?
populations of all the species present in an ecosystem at a particular time.
what is a habitat?
the places where specific organisms live
What are consumers?
organisms whish eat other living things (e.g. animals)
what are decomposers?
organisms which secrete digestive enzymes to decay (breakdown) dead organic matter to obtain their food; they help to recycle nutrients
what are producers?
organisms which make their own food (e.g. photosynthesising plants)
what does abiotic mean?
Non-living factors which affect growth and survival of living things. e.g. temperature, carbon dioxide and oxygen concentrations, minerals in the soil
Method: population size of a species in an area - 5 marker
- tape measure placed at right angles to
form a grid - random number generator
- co-ordinates e.g. 2,11
- place quadrat ( known area)
- count the number of species in the
quadrat - repeat x10 –> calculate the mean
- scale up to the size of field/area
Method: Comparing biodiversity differences between field A and B
Field A
- tape measure placed at right angles to
form a grid
- random number generator
- co-ordinates e.g. 2,11
- place quadrat ( known area)
- count the number of species in the
quadrat
- repeat x10 –> calculate the mean
Calculate biodiversity using equation
Then repeat for Field B and compare
Pyramids of number
these are drawn to show the number of
each organism counted in the ecosystem. They can be odd shapes due to the different masses of organisms.
Pyramids of biomass
these are drawn to show the total mass of the organisms in each trophic level (i.e. the mass of an individual x the number of individuals). These are a more accurate way of looking at the relative amounts of organisms.
pyramids of energy
these are drawn to show the total energy available in each trophic level per
square metre per year. There should be a decrease in energy between each trophic level.
why is the least efficient transfer is from light energy to the producer?
- Some light will miss the plant or miss the plant’s chloroplasts.
- Some light will be reflected by the cuticle
- Some light has the wrong wavelength to be absorbed by chlorophyll