OCR A Level ELSS - Entire Course 4 Flashcards
biological weathering
the breakdown of rocks through the chemical and physical action of living organisms, e.g. burrowing, tree roots
chelation
a type of chemical weathering by acids derived from rainwater and dead organic matter
canopy
the uppermost layer of treetops and branches in a forest or woodland ecosystem
biodiversity
the number of different plant, animal, fungi etc species in a given area
downwelling
the sinking of dense, salty (or cold) water in the oceans
upwelling
The movement of deep, cold, and nutrient-rich water to the surface
food chain
a series of organism through which food energy moves before it is completely expended
lithification
the transformation of sediments into rock (usually by compression and/or heating)
orographic effect
changes to air flow due to the topography of the land e.g. mountains forcing air to rise
absolute humidity
the mass of water vapour in a given volume of air
relative humidity
the mass of water vapour in a given volume of air as a ratio of the mass needed to saturate it
biomass
A measure of the total dry mass of organisms in a given area
porous rock
rocks which contain pores or air spaces between mineral particles, where water can be stored
nutrient cycle
the continuous movement of nutrients between stores (soil, biomass and litter)
shifting cultivation
A form of subsistence agriculture in which people shift activity from one field to another
commercial farming
agriculture on an industrial scale operated by large companies using heavy machinery
commercial logging
forestry on an industrial scale operated by large companies using heavy machinery
commercial mining
Mining on an industrial scale operated by large companies using heavy machinery
monoculture
the cultivation of a single crop in a given area.
small scale agroforestry
use of small areas of forest to grow crops, raise animals and harvest raw materials, considered to be sustainable
tree line
the latitudinal and altitudinal limit of tree growth.
heat balance
the difference between solar inputs of energy to the Earth-atmosphere system and energy outputs from terrestrial radiation and gases in the atmosphere. Currently inputs exceed outputs and the global climate responds by warming
active layer
the upper layer of permanently frozen soil that thaws briefly during the summer
dynamic equilibrium
a system displaying unrepeated average states through time