4.2 Energy flows Flashcards
What is teh initial source of energy in the majority of ecosystems?
Sunlight - light E is absorbed and converted into chemical E via photosythesis
Other ecossytems rly on chemoautotrophs whihc produce E from oxidation fo inorganic substances
What is a trophic level? What trophic levels exist?
TROPHIC LEVEL: the position of an organism in the food chain
Give an examples of a terrestrial and marine food chains
TERRESTRIAL: flower -> grasshopper -> mousee -> snake -> eagle
MARINE: phytoplankton -> shrimps -> cod -> seal -> killer whale
How many percent of energy are transerred to the next trophic level? Why only that?
10%
- E used for metabolism, growth, homeostasis, movement
- chemical by-product heat is lost
- lost in excretion
- not all tissues are consumed: ex bones, fur (decomposers can use)
Why do higher trophic levels need more food?
- because the E and biomass are lost through trophic levels - least amount consumed by highest trophic level (number of trophic levels is limited)
- larger organisms
Explains why lower trophic levels produce more offspring and higher less - environment is in balanced due to consumption
How to draw a pyramid of energy?
Graphical representation of E passed to each trophic level in a food chain
UNITS: kJ m–2 year–1
Each level 90% smaller (10% E passed)
When a pyramid is drawn - must fit into all of the given area
What is a food web?
FOOD WEB: diagram which represents how several food chains are related