Energy and Ecosystems Flashcards
what is a producer
photosynthetic organisms
that manufacture organic substances using light energy,water,carbon dioxide
and mineral ions
what is a primary consumer
organisms that consume producers
what is a secondary consumer
an organism that consumes a primary consumer
what is a tertiary consumer
an organism that consumes a secondary consumer
what is a consumer
organisms that obtain energy by feeding on other organisms rather than using sunlight directly
what is a trophic level
a level in a food chain
what is biomass
the total mass of living material in a specific area in a given time
why is using dry mass better than bio mass
bio mass involves the water levels which vary day to day
how do you remove the water from an organism
weigh and heat sample so water evaporates
heat until mass remains constant
what % of the light energy from the sun is converted to chemical energy in plants
1-3%
give 4 reasons why all of the light energy from the sun is no converted to chemical energy in plants
- not all wavelengths of light are absorbed
- some light is adsorbed or reflected by clouds or atmosphere
- light may not fall on a chloroplast molecule
- temperature or CO2 conc may limit the rate of photosynthesis
what are saprobionts
fungi and bacteria that
break dead and waste material
what % of energy at each stage of the food chain
10%
what do saprobionts do to do dead and waste matter
the secrete enzymes onto dead and waste material to break it down
what do saprobionts do to organic molecules
organic molecules are broken down into inorganic molecules
what do saprobionts do to smaller molcules
they absorb smaller molecules and use them for storage/respiration
outline nitrogen fixation
nitrogen-fixing bacteria
covert nitrogen gas to ammonium ions
outline nitrification
nitrifying bacteria convert ammonium ions to nitrite ions and then nitrite ions to nitrate ions
how are phosphate ions in rocks released into the soil
phosphate ions in rocks are released into the soil by weathering
what do plants do to the phosphate ions that are released into the soil
they take up phosphate ions through their roots
mycorrhizae greatly increase the rate at which phosphate can be assimilated
what is mycorrhizae
a symbiotic relationship between plants and fungi benefitis both species
what happens to the phosphate ions after plants absorb them
phosphate ions are transferred through the food chain as animals eat the plant and are in turn eaten by other animals
how are phosphate ions lost from animals
phosphate ions are lost from the animals in waste products
outline assimilation
nitrates are used to make amino acids and proteins
outline ammonification
saprobionts break down organic molecules into ammonium ions
outline dentrification
dentrifying bacteria convert nitrate ions into nitrogen gas
what happens to minerals in the soil in intensive farming
minerals are removed from the soil and not being returned
why do we use fertilisers
to the replace the mineral ions that are removed from the soil in intensive farming
what do saprobionts do to animals and plants when they die (phosphorous cycle)
they are involved in the breaking down the organic compounds, releasing phosphate ions into the soil for assimilation by plants they also release the phosphate ions from urine and feaces
how are phosphate ions released into rivers and how are they taken up
weathering of rocks releases phosphate ions into rivers
they are taken up by aquatic producers such as algae and passed along the food chain to birds
what is the waste produced by sea birds called and what it is it’s role in phosphorous cycle
it is called guano and contains a high proportion of phosphate ions it returns a significant amount of phosphate ions to soils
what are the two types of fertilisers
natural organic fertilisers
artifical inorganic fertilisers
what are natural organic fertilisers made from
dead and dying plants as well as plants and animal waste
what are artifical inorganic fertilisers made from
rocks that have been mined they contain NPK
what are the problems with fertilisers
reduced species diversity
leaching
eutrophication
why do fertilisers cause reduced species diversity
as NPK fertilisers favour the growth of rapidly growing species,grasses and nettles
as they absorb more light and compete for space far better
outline leaching
fertilisers and mineral ions dissolve in rainwater and run off into lakes, rivers and streams
what is gross primary production
the total amount of chemical energy converted from light energy by plants in a given area
what are respiratory loses
the gross primary production lost to the environment as heat when the plants respire
