Energy transfer Flashcards
in any ecosystem , what are plants known as ?
- the producers
in any ecosystem what do plants synthesise organic compounds from ?
- atmospheric or aquatic carbon dioxide
why are plants known as the producers ?
- because they are able to produce their own carbohydrates using carbon dioxide in the atmosphere or in the water
between each trophic level in a food web, why is the majority of the energy lost ?
- due to excretion and respiration
what is the remaining energy from the trophic levels used to form ?
- biomass
how can the biomass remaining in an organism be measured ?
- it can be measured in terms of mass of carbon or dry mass of tissue per given area per given time (Kg per m2 per year )
what are the 2 categories of producers ?
- autotrophs
- photoautotrophs
what is meant by an autotroph ?
- an organism that makes its own food
what are examples of photoautotrophs ?
- terrestrial plants
- aquatic plants
what is meant by a photoautotroph ?
- they make their own food from photosynthesis
what are most of the sugars/glucose synthesised by plants are used as ?
- they are used as respiratory substrates in respiration
how are glucose and other sugars synthesised by plants ?
- by photosynthesis
what are the rest of the sugars produced by photosynthesis by plants used as ?
examples?
- rest of the glucose is incorporated into other biological molecules
- e.g sucrose, cellulose, starch
what is sucrose, cellulose, starch etc known as in the plants ?
- referred to as the biomass of the plants
why are plants and trees considered to be the producers of all ecosystems ?
- they perform photoautotrophy
- where they convert sunlight into organic matter
- which forms its biomass
what is meant by biomass ?
- the mass of living material stored in an organism
- the amount of chemical energy stored in the bonds of molecules that the organism contains
when an organism consumes other organisms what is transferred ?
- energy
what are producers consumed by ?
- primary consumers
- herbivores
what are primary consumers consumed by ?
- secondary consumers
- carnivores
describe one practical way to measure biomass ?
- calculate the dry organic mass of an organism
- organism is dried and weighed in regular intervals by heating in a low temp oven
- mass of an organism will remain constant when all of the water is removed
what is the mass of the carbon of an organism estimated to be ?
- estimated at 50% of the total dry mass
what can calorimetry be used to estimate ?
- the chemical energy store in dry biomass
describe what occurs in calorimetry ?
- the sample is burnt to release kinetic energy
- the kinetic energy is used to heat a known volume of water
describe how bomb calorimetry is used ?
- a known volume of water is added to a sealed vessel
- the biomass is ignited and the change in temp is used to calculate the amount of chemical energy released
