IB Biology HL : energy transfers ecosystems

food

fundamentral concepts

• energy is lost as they go up the food chain

• ecosystems are affected by changes in the availability of energy and matter

• biological processes depend on energy flow through earth’s system

• the sun is the main source of fuel for ecosystems

• food is a biofuel required by organisms to acquire energy for internal living processes

• energy available to do useful work decreases as it’s transferred from organism to organism

• energy flows though food webs in one direction from producers to consumers to decomposers

• ecosystems are affected by changes in the availability of energy and matter.

• humans are part of the earth ecosystem and influence energy flows through these systems

why does the total biomass of organisms higher up in the foodchain higher

• some parts are not consummable; bones, hooves, horns

• not all biomass is used; some isn’t consummed

• some is lost to respiration

chemoautotrophs

oxidation of non-organic molecules, in unhospital conditions, eg sewers, geothermal vents

biomass

dry mass of organisms

pyramid of biomass advantages or disadvantages

gram m^-2

good

• takes into account mass

bad

• doesn’t take account of variation around year

• some of the mass doesn’t get used up

pyramid of energy

kcal m^-2 yr^-1;

takes into account year on year variation

always are pyramid shaped