The efficiency of ecosystems Flashcards
What are trophic levels
Each level pf a food chain is called a trophic level
How is energy lost from each trophic level
Some parts of the food are not or cannot be eaten e.g. bones etc.
Some foods cannot be digested
Energy is lost to the environment as heat and waste
What are the 3 types of ecological pyramids
Pyramids of numbers
Pyramids of biomass
Pyramids of energy
Pyramids of numbers
In many food chains, the number of organisms decrease at each trophic level e.g. more plants than insects, more insects than birds and more birds than foxes
Pyramids of biomass
Shows the combined mass of all organisms in a particular habitat as pyramid of numbers does not accurately represent the whole ecosystem
Dry biomass is more accurate than wet
Pyramids of energy
Pyramids of biomass fail to show the levels of reproduction
The energy in an ecosystem remains the same at every level but the size and type of energy store changes
How much energy is passed on at each stage
Roughly 10%
What is the formula for calculating energy efficiency
Energy transferred to biomass / total energy supplied to an organism
What is the glucose produced in photosynthesis used for
Used to build organic material in plants (biomass) - start or the food chain hence why they are called producers
Energy flow
Is unidirectional through living organisms and is eventually lost to the environment as wasted heat
Matter
Continually recycled between living and non living things
Where do nutrients exist
Stores which we call sinks
Biotic phase
Where the chemical or mineral ions (inorganic molecules) are incorporated into the tissues of living things (organic molecules)
Abiotic phase
Where the chemicals or mineral ions are returned to the non living part of the ecosystem (inorganic molecules)
Carbon sinks - biotic
Inside organisms as carbon based molecules e.g. proteins
Carbon compounds in plants e.g. starch and cellulose
Carbon sinks - abiotic
Dead organic matter in soil
Fossils
Carbonate rocks
Atmospheric carbon
Which biological molecules contain nitrogen
Proteins
Nucleic acids
Chlorophyll
Nitrogen sinks - biotic
Inside organisms such as proteins, DNA and chlorophyll
Nitrogen sinks - abiotic
Nitrogen in the atmosphere
Ammonia and urea in waste
Nitrates in soil
Dead animals and plants
Why do plants need nitrogen
To make proteins
Organism that break down dead plants or animals
Decomposers
What are the different forms of nitrogen
Nitrogen gas - plants cant absorb nitrogen from the air
Complex nitrogen compounds - present in live and decaying plants / animals underground
Simple nitrogen compounds - formed from the breakdown of complex nitrogen compounds by decomposers, plants can absorb these through their roots
Processes that increase nitrates in the soil
Lightning - energy causes unreactive nitrogen gas in air to form nitrates
Decomposers (nitrifying bacteria) - oxidise ammonium compounds from dead plants / animals to form nitrites and nitrates
Nitrogen fixing bacteria - bacteria in root nodules of legumes convert nitrogen gas from air into simple nitrates for plants to absorb through roots
Gross primary productivity
Rate at which plants capture sunlight to produce new plant material
