energy transfers

explain how energy enters an ecosystem

• Energy enters an ecosystem primarily through the photosynthesis of producers, which are organisms like plants that capture light energy from the sun and convert it into stored chemical energy such as glucose.

• This energy is then transferred through the food chain when consumers eat the producers and other consumers.

explain how the following organisms obtain their energy;

• producers

• consumers

• saprobionts (decomposers)

• producers- photosynthesised and produces its own sugars from the suns light energy. energy stored as glucose

• consumers- obtains energy from consuming an organism

• decomposers- obtains nutrients by digesting dead or waste organic mater

what is meant by;

• a trophic level 

• food web

• ecosystem 

• biome 

• trophic level- a stage a food chain 

• food web- several food chains connected

• ecosystem- living organisms interacting in their non living environment

• biome- a large geographic region defined by its characteristic climate, landscape and types of organisms living there

what is biomass and how is it measured?

• the mass of organic material or chemical energy stored in an organism

• it can be calculated In terms of mass of carbon in dry mass of organism in its tissue are per unit area per unit time (50% of dry mass)

• can calculate the chemical energy stored in organism by doing a calorimetry experiment on dry mass of an organism by burning it and using heat evolved to heat a mass of water

how is energy transferred between organisms in an ecosystem?

• energy is transferred when organisms consume other organisms

• producers —-> primary consumers —→ secondary consumers —→ tertiary consumers

• this is known as a food chain

what percentage of energy is transferred from one trophic level to the next. 

what happens to the % that isn’t transferred 

• 10% 

• the remaining 90% is lost as heat from respiration, used for metabolic processes, excreted as waste (faces and urine) or stored in undigested material 

explain how energy is lost in the food chain starting at producer

• 1% of suns energy is absorbed by plant to be used in photosynthesis. some reflects, misses the chlorophyll and passes through the leaf or is the wrong wavelength

• not all of the organism is consumed e.g. bones or cellulose

• energy lost via waste- faces or urine

• energy lost through heat loss during respiration

what is the calculation for efficiency of energy transfers?

% efficiency= energy available after transfer / energy avalable before transfer x 100