Feeding relationships

what does a food chain always start with and example

with a producer - a photosynthetic organism, produces glucose through photosynthesis. e.g grass

why is producer called a producer

they use photosynthesis to produce their food, using energy from sunlight- where all energy in food chain comes from

what is the second part of a food chain and example

primary consumer, they eat the producers egm mice, rabbits

why are primary consumers called that, what are they always

they are the first organisms in the food chain that consume other organisms - herbivores( plant or algae)

what is the third part of the food chain and example

secondary consumer, they eat the primary consumer e.g owl, a predator

why are secondary consumers called that, what are they always

second level of consumers in the food chain, always carnivore, eat another animal

what is the fourth part of a food chain and exampl

tertiary consumers,( some chains may have more)

what do the arrows show, does energy get lost?

the flow of energy up the chain - energy gets lost each time, and biomass

why does the out of phase, predator-prey cycle not reach equilibrium

takes a long time for entire populations to increase, or descrease

what are trophic levels

different levels of a food chain, grass 1 —> owl 4

why are there only usually 4 or 5 trophic levels

because their is not enough energy to sustain organisms in a higher trophic level

whats the general rule for how much energy gets passed on in a food chain, trophic levels

10% is passed on

what organisms don’t fit into the pattern

bears - omnivores,

what do detritivores and decomposes both do, which does what

decompose the dead plants and animal matter in the environment which then recycle nutrients from animals and plants baack into the ground for producers

example of detritivores and decomposers

detritivores - worms

decomposers - bacteria, fungi

what do pyramids of biomass show

shows the biomass of each trophic level in a food chain

what does each bar in a pyramid of biomass show

the biomass of all organisms in that trophic level

what is biomass

the mass of living organisms

what does it mean as every bar gets smaller

that total mass is decreasing

what are the 3 main reasons why only 10% of the biomass gets passed on

1. organisms don’t normally eat every part of- wouldn’t eat skeleton or teeth

2. bits they do ear might not be absorbed - gets egested as faeces

3. most of the nutrients that animals absorb are used to release energy through respiration- biomass released as waste proctucs: urea, carbon dioxide, usses for everyday functions most important point

example of organisms not absorbing all food

rabbits may not be able to digest all the cellulose in grass, or eat roots for not fully eat

equation for efficiency of biomass transfer

efficiency=biomass transferred to next level/ biomass that was available at previous level X 100