U1T4 - Keywords (2) Flashcards
Ecological Energetics + Nutrient Cycling
Photoautotrophs
Producers that make their own food from inorganic molecules, water + carbon dioxide using sunlight as energy source.
Chemoautotrophs
Producers that use chemical energy to make own food (bacteria in dark caves, make organic substances using minerals in rock as source of chem energy) e.g. nitrifying bacteria.
Autotrophs
Producers which make own food + therefore provide food for all other species in ecosystem directly or indirectly.
Heterotrophs
Can’t make own food so rely on other living organisms to provide them with organic molecules. Consumers.
Trophic Levels
Feeding Levels. Producers = 1st TL. Primary Consumers + 2nd TL etc. Most ecosystems have 3/4 but aquatic may have 6.
Detritus Food Chains
Food chains starting with dead organic matter. Dead plants + animals fed upon by detritivores + decomposers.
Food Webs
Pattern of interrelated food chains operating in an ecosystem.
Pyramid of Numbers
Bar diagram indicating relative num of organisms in food chain/total num of all organisms at each trophic level in food web.
Inverted Ecological Pyramid
Top Heavy Pyramid (of Numbers/Biomass)
Pyramid of Biomass
Shows mass of living organisms at each trophic level, per unit area/volume at certain time. Illustrates total biomass at each TL.
Biomass
Mass of living material present at given time.
Wet/fresh mass
Weighing live organisms as they are.
Dry mass
Drying organisms until constant mass achieved, more accurate than wet mass but more time consuming and kills organism.
Standing Crop
Num of organisms present at any one time. (with biomass)
Pyramid of Energy
Takes into account productivity for each TL in ecosystem during fixed period of time. (1 year takes into account annual changes so units are kJ.m^-2.y^-1.
Productivity
How much new material produced.
The sun
The ultimate energy source for all ecosystems.
Photosynthesis
The route by which energy is made available to the ecosystem.
GPP
Gross Primary Production. Energy in organic compounds produced by plants in photosynthesis (units kJm^-2yr^-1 or biomass per metre squared per year). Not all of this is available for next trophic level as some (50%) used in resp.
NPP
Net Primary Production. Represents rate of production of new biomass which is available for consumption by heterotrophic organisms. If plants die, NPP in form of dead leaves/flowers forms detritus. GPP - R.
Detritus
NPP in form of dead leaves/flowers.
Heterotrophic Organisms
Only energy source in ecosystem for next trophic level.
Trophic Energy
Percentage of energy at one TL which ends up in next TL.
Herbivores
Obtain energy by eating primary producers. Only 5 - 10% of energy gets transferred to them. e.g. deer + pandas
Primary Consumers
Feed on producers e.g. aphids + rabbits
Secondary Consumers
Feed on primary consumers e.g. ladybugs + skunks
Tertiary Consumers
Feed on secondary consumers e.g. owls + humans
Carnivores
Organisms which feed on other animals e.g. hyenas + whales
Detritivores
Organisms involved in decay + decomposition. Feeds on dead organic material. e.g. sea cucumbers + dung beetles
Decomposers
Organisms involved in decay + decomposition. Decomposes dead organic material. e.g. snails + mushrooms
Grazing Food Chain
Starts from the autotrophs (green plants), energy is taken from the sunlight as green plants prepare food in the presence of it.
Omnivore
An animal that eats both plants and animals.
Producer
Organisms that make organic substances from inorganic substances using energy. Almost all use light energy to do this. Some use chemicals (chemoautotrophs)
Consumer
Organisms that obtain energy by feeding on other organisms.
Energy Transfer Inefficiency
When energy is transferred by an appliance the energy is converted from one form to another. Some of the energy will be usefully transferred by the device and some will be wasted.
Endotherms
An animal dependent on/capable of internal heat generation.
Fertilisers
Chemical/natural substance added to soil/land to increase fertility.
Pesticides
Substance used for destroying insects or other organisms harmful to cultivated plants or to animals.
Energy Budget
An energy budget is a balance sheet of energy income against expenditure. P= C - (R + U + F)
Net Secondary Productivity
The biomass gained by heterotrophic organisms, through feeding and absorption, measured in units of mass or energy per unit area per unit time (minus what is lost)
Food Chain
Shows link between producer, primary consumer, secondary consumer + potentially tertiary consumer. Not v.realistic.
Silage
Cut grass/maize chopped into small pieces + stored in anaerobic conditions (covered in plastic). It creates lactic acid, low pH stopping other decomposing microbial growth preserving high nutrient status. Partial decomp.
Secondary Productivity
Productivity in animals. Energy used in production of new tissue in animals. Worked out using energy budgets.
