Chapter 3.5 Energy Transfers Flashcards
Types of energy loss between sunlight and producers?
(Only about 1-3 % absorbed)
- some light reflected back to space
- some light misses chlorophyll molecules & passes through leaf
- wrong wavelength of light (only red/blue absorbed)
- low rates of photosynthesis due to other limiting factors
Ways energy lost between consumers?
- Some parts organism not consumer & digested
- energy loss in urine and faeces
- energy loss as heat from respiration
What is energy available in ecosystem measured in?
KJ m^-2 year^-1
KJ/m2/year
How many trophic levels in ecosystem
+ why is there a max?
Limited to 4/5 because insufficient energy available to support large enough breeding population for more
Calc of net production of consumers
N = I - (F + R)
N = net production of consumers
I = chemical energy store of ingested food
F = energy lost in faeces and urine
R= energy lost in respiration
Calc of net production of producers?
N = I - R
N= net production
I = gross production
R = respiratory losses
Calc for Energy transfer efficiency
Energy transfer. Energy available after transfer
Efficiency =. ———————————————— x 100
Energy available before transfer
What is biomass measured in terms of
Mass of carbon than an organism contains or the dry mass of its tissue per unit area.
How do you produce dry mass of biomass?
1) sample of organism is dried, often in an oven at low temps
2) Sample then weighed at regular intervals
3) once mass is constant all the water has been removed
4) mass of carbon is generally 50% of the dry mass.
5) once measured dry mass scale up result of total population or the area being investigate.
How do you use calorimetry to work out energy in biomass?
A sample of dry biomass is burnt and the energy released is used to heat known volume of water.
Change in temp if water is used to calculate energy of dry biomass.
Energy measured in J or KJ
What do food chains and webs show?
The energy transferred through an ecosystem
How can farmers increasing efficiency for plants/ livestock to human consumption
+ explain ways it can be done
- reduce energy loss to other organisms, e.g. Pests, by simplifying food web
Getting rid of food chain that don’t involve humans can reduce energy loss this can be done by
Using pest controls to get rid of pests (chemical agents or biological agents) - reduce energy lost through respiration of livestock
Control the conditions that they live in : restricting movements, indoor pens so warmth
so more energy used for growth rather than respiration.
Benefit are more food, produced in smaller space of time, often lower cost. This can raise ethical issues.
Role of Saproobionts in food webs and ecosystem?
- feed on remains of dead biomass and on their waste products, breaking them down.
This makes them decomposer and allow chemical element and waste to be recycled - secrete enzymes and digest their food externally, then absorb the nutrients they need- extracellular digestion. This process turns organic molecules -> inorganic ions
What is Mycorrhizae?
Symbiotic relationship some fungi form in the roots of plants.
Role of Mycorrhizae in uptake of plants
For plants in soils scarce in ions/ nutrients
The fungi made up long, thin strands called hyphae , which extend plant’s roots.
These ⬆️ SA, ⬆️ absorbtion of ions and water from the soil that are usually scarce.
In turn, fungi obtain organic compounts from the plant to survive.
