Flashcards in B2b-energy flow Deck (14)
what is a trophic level?
a feeding level
Position occupied by a group of organisms in a food chain
What is a producer?
Organisms that make their own food
Eg lettuce -sunlight
What is a primary consumer?
What is a secondary consumer?
Eat first consumers
What does a pyramid of biomass show?
Shows the mass of living material at each stage of the food chain
Why is it difficult to measure dry biomass?
You have to kill the organism first to dry out all the water
Why is it difficult to construct an accurate pyramid of biomass?
Some organisms feed at more than one trophic level
Why can pyramids of biomass and pyramids of numbers be different shapes?
Pyramids of biomass mostly pyramid shape
Pyramid of numbers-number of organisms
How does energy from the sun flow through food webs?
Plants use some light energy from sun to make food
What is egestion?
When food that can't be digested passes out as faeces
How is energy or material lost at each stage?
Energy lost as heat to surroundings
What happens to waste products and uneaten parts?
They can become starting points for other food chains
Why do most food chains have no more than five trophic levels?
Material and energy lost at each stage of food chain
Not enough energy to support more organisms