4.2 Flashcards
What is a food chain
The sequence of energy flow from producers through consumers
What is a trophic level
a trophic level refers to the position of an organism in a food chain
What is a food web?
models of ecosystems that represent many different food chain possibilities and how they are interconnected
Name a food web example
Decomposers (worms) - Producers (plants) - Primary consumers (grasshopper and squirrel) - Secondary consumers (frog and snake) - tertiary consumers (fox and hawk)
How is energy lost between trophic levels
when something is eaten, it is not entirely consumed, so they are left and the entry in them does not continue in the food chain. Some material that is eaten is indigestible and leaves the body with the faces through digestion. Some energy is still contained in the waste material (urine and faces). This becomes available to detrivores and saprotrophs.
What is the amount of energy each trophic level transfers
10 to 20%
What is biomass
the mass of dried organic material which can be used as fuel in an ecosystem, expressed in terms of dry weight per unit area.
How does biomass change in the food chain
As the trophic levels increase, biomass decreases.
How many trophic levels are there on average
Around five trophic levels as every keeps being lost.
What accounts for restricted length of food chains?
Low efficiency of energy transfer between trophic levels
How can energy be regained in ecosystems
Photosynthesis
