4.5c- pyramids

- to quantify the number of consumers per tropic level, we use a pyramid of number
- for example, 1000 carrot plants, 100 carrot flys, 10 fly catchers and 1 sparrow hawk
- this can be turned into a diagram used to illustrate this
- it must be made clear how large the organism it represents is i.e. a tree. this is because you cannot start with a small amount of energy and end with a large amount
- another method is the pyramid of biomass bio= living, mass= amount (g/km)
- a pyramid of biomass is based on the amount of dry mass in a organism
- this method is difficult because everything must be dryed out first
- the third is the pyramid of energy transfer
- this cannot be inverted
- units of enery are used (joules, kilajoules)
- units of area (m) and units of time (s/mins)
- pyramid of number is the easiest pyramid to use because the pyramid of energy is very time consuming

4.5b- food webs

- food webs show organisms feeding at different tropic levels, unlike food chains which can't show more than 2
- orgaisms can have multiple preditors
- or feed on multiple prey, these two become linked

4.5a- food chains

- food chains link all the consumers together
- there is one organism per tropic level
- food chains show the flow of matter and energy

4.4- tropic levels

- tropic = feed
- producers are plants which photosynthesis
- herbivores eat the plants, this is the primary consumer
- carnivores eat the herbivores or any other animal, this is the secondary consumer
- a carnivore eating another carnivore is a top carnivore or a tertiary consumer
- when all of these die, these are broken down by decomposers
- decomposers = fungi and bacteria

4.3- quadrat samples

- the sample must be random (preventing bias)
- must be representative (large enough to get an accurate estimate)
- the field gets broken down into squares and numbered- then you need random numbers for the x and y coordinates
- ater the numbers are found, the organisms are then counted
- a good sample is about 10% of the actual area
- results get put in a table and you add the number of organisms and then divide by the number of quadrats

4.2- quadrats

- quadrats are used to count the population size of organisms

- quadrats are square grids made out of anything to lots of squares in the grid

- they are sampled in two areas so that both areas can be compared

obj 4.1- ecosystems

- a habitat is the abiotic factors of an ecosystem. This includes:
day and night
temperature
rainfall
humidity
geology
this describes everything which is non-biological

- a community is made up of populations of different species interacting together

- a population is the number of individuals of a particular species

-a species are organisms that reproduce

-an ecosystem is a community of organisms in a particular habitat