Energy transfers and nutrient cycles Flashcards
what is biomass
the mass of carbon or dry mass of tissue per given area or volume
compare fresh and dry mass
- fresh mass is living, dry is dead
- fresh mass is easy to access , dry is difficult
- fresh mass has variable water content, dry mass has a small sample size which may not be representable
- both are unreliable
describe the energy transfer from the sun to the producer
- some light energy is reflected
- some light energy is absorbed by gases in the atms
- some light energy is the wrong wavelength
- some light energy does not strike the chlorophyll
what is NPP available for;
NPP= GPP - R
- plant growth
- plant reproduction
- other trophic levels
describe the energy transfer from the producer to the primary consumer
1- large amounts of plants may be indigestable and lost from the animal as faeces
2- not all of the plant may be eaten
3- some energy is lost in excretion
4- energy lost in respiration and as heat to the environment
describe the energy transfer from the primary consumer to secondary
1- large amounts of plants may be indigestable and lost from the animal as faeces
2- not all of the plant may be eaten
3- some energy is lost in excretion
4- energy lost in respiration and as heat to the environment
energy that is stored as new biomass is available to the next trophic level
why are these energy transfers inefficient
- large losses at each trophic level
- not enough energy to support a breeding population
equation for net production of consumers
N= I - (F + R )
Percentage efficieny
energy after/energy before x 100
yield can be determined by measuring the dry mass of plants. suggest how
- heat at 100c
- weigh and heat until no further change in mass
what is the advantage of using dry mass ?
- water content is variable
- will not affect dry mass
ways to increase energy conversion rates in domestic livestock
1- restricting movement so less respiratory loss due to muscle contractions
2- keeping animals warm and indoor to reduce heat loss from body
3- more nutritious food
4- selective breeding
5- slaughtered before reaching adulthood so more energy transferred to biomass
where is nitrogen found?
amino acids
proteins
DNA/ RNA
ADP / ATP
NADP
NAD & FAD
name the four stages of the nitrogen cycle
1- nitrogen fixation
-nitrogen fixing bacteria
-nitrogen gas to ammonia NH3 / NH4+ ions
-reduction
2- decomposition
-using saprobionts
- nitrogen containing compounds to ammonia NH3
- ammonification
3- nitrification
- ammonia –> nitrites –> nitrates
- NH3 –> NO2- –> NO3-
-oxidation
-assimilation absorbed by plants
4- denitrification
- denitrifying bacteria
- NO3- –> N2
describe how the action of microorganisms in the soil produces a source of nitrates for crop plants (5)
- protein/DNA converted to ammonium
- by saprobionts (secrete extra cellular enzymes )
- ammonium into nitrite
- nitrite into nitrates
- by nitrifying bacteria
- nitrogen gas to ammonia
- by nitrogen-fixing bacteria
