Food Webs Flashcards
What is the ultimate source of energy?
The Sun
Define Producer
Photosynthetic organisms that obtain that manufacture organic substances
Define Consumer
organisms that obtain energy by feeding on other organisms can be primary, secondary or tertiary
Define Saprobiont
Organisms that break down complex materials in dead organisms into simpler ones
usually bacteria and fungi
What do Food Chain show?
What does the arrow represent?
What is the name given to each level?
describes feeding relationships
arrow= direction of energy flow
each stage = trophic levels
What do Food Webs show?
shows the complexity of feeding relations
Define Biomass ( units)
Biomass can be measured in terms of mass of carbon or dry mass of tissue per given area.
What does calorimetry measure?
Calorimetry measures the chemical energy store in a dry mass
Describe how calorimetry could measure the chemical store
Sample dried by heating in an oven to evaporate all the H2O off
Weigh samples, place in a cup and ignite in O2 rich atmosphere
The heat from combustion is transferred to the water
Thermometer records the temperature of the H2O
Why is most the suns energy not converted?
Energy is reflected into space or absorbed by the atmosphere
Not all the wavelengths can be absorbed and used 4 photosynthesis
Light may not hit a chlorophyll molecule
Another factor may be limiting eg CO2
What is the equation for Net Primary Production? ( in plants)
NPP= GPP-R
When GPP= Gross Primary Production and R =respirtiary losses
Why is energy lost at each trophic level?
Some of the organism is not consumed
Some consumed parts cannot be digested so lost as faeces
Some lost as excretory materials
Lost as heat from respiration to the environment
What the equation for net production in animals?
N= I - ( F+R)
When I= chemical energy of Ingested Food
F= energy lost in faeces and urine
R= energy lost in respiration
What does inefficient energy transfer explain?
why food chains only have 4 or 5 trophic levels
biomass is less at higher trophic levels
the total amount of energy available is less up the chain
What is the equation for percentage efficiency?
the energy available after the transfer / before transfer x100
