manipulating biomass transfer Flashcards
what is productivity
rate of production of new biomass by producers
what is gross primary productivity-
rate that plants convert light energy to chemical energy by photosynthesis
why is only a small percentage of light energy from the sun entered into the light reaction of photosynthesis
some is reflected.
only certain wavelengths stimulate photosynthesis
how can light levels be manipulated by humans to make energy conversion more efficient
plant crops earlier and ensure a longer growing season to harvest more light
light banks- grow crops under light banks and ensure constant supply of light energy
how does growing plants ina greenhouse increase photosynthesis
provides a warmer temperature and increases the rate of photosynthesis, increasing rate of biomass production
what manipulations are made when there is a lack of nutrients
crop rotation- growing new plants on a rotational cycle prevent reduction of inorganic material such as nitrate in soil.
what crop can replenish nitrogen levels
legumes- peas or beans.
as they contain nitrogen fixing bacteria such as rhizobium.
how does spraying pesticides help
because insects eat crops and remove biomass from food chain, and lower yield.
pesiticides prevent bugs
what genetic modification can be made to plants
genetically modifying plants to be pest resistant
what is secondary productivity
rate of secondary production by consumers
why do primary consumers not make full use of plant biomass
some plants die
consumers dont eat all of plant, e.g. dont eat root
they dont digest everything they eat- cellulose
egestion- faeces
respired
what is the process of making faeces
egestion
what part of the plant is indigestable
cellulose, makes transfer of biomass inefficient from producer to primary consumer
how do humans manipulate secondary productivity rates
harvest animals young to minimise loss of energy from food chain
selective breeding
treat animals with antibiotics to reduce loss of energy to pathogens
why do farmers kill animals young rather than old
because young animals invest lots of energy into growth rather than losing energy by other processes.
