Food Chains
A food chain is shows one possible energy flow from one species to the next. There are no alternative routes. It's very clear who gets energy from who.
The Arrow - The arrow means energy moves from here to here. It does NOT mean this guy eats this guy. That would be backwards. In our picture to the left the plant gives its energy to the worm, the worm gives its energy to the turtle, and the turtle gives its energy to the eagle.
The Arrow - The arrow means energy moves from here to here. It does NOT mean this guy eats this guy. That would be backwards. In our picture to the left the plant gives its energy to the worm, the worm gives its energy to the turtle, and the turtle gives its energy to the eagle.
Food Webs
A food web is like a food chain in that it shows where the energy is transferred but unlike a food chain it has multiple pathways to follow. The mayfly in the picture can get eaten by the frog, salamander, or trout. The food web gives you a wider view of an ecosystem
Trophic levels - The levels that show placement on a food chain. They are:
Producer - any plant. Usually they do photosynthesis and get their energy from the sun
Primary Consumer - The species that eats the producer
Secondary Consumer - The species that eats the primary consumer
Tertiary Consumer - The species that eats the secondary consumer
Quaternary Consumer - The species that eats the tertiary consumer
After Quaternary it goes 5th order, 6th order, etc.
So I could ask questions about the food web like this:
If a human eats a trout that ate phytoplankton, what trophic level would he be?
If a human eats a trout that ate a dragonfly that ate phytoplankton, what trophic level would he be?
If the snake ate a salamander that ate a mayfly that ate phytoplankton, what trophic level would he be?
Answers:
Secondary (phytoplankton is "the grass of the sea" so it's the producer, trout is the primary consumer, the human is the secondary consumer)
Tertiary (phytoplankton is "the grass of the sea" so it's the producer, the dragonfly is the primary consumer, the trout is the secondary consumer, and the human is the tertiary consumer)
Tertiary (phytoplankton is "the grass of the sea" so it's the producer, the mayfly is the primary consumer, the salamander is the secondary consumer, and the snake is the tertiary consumer)
Trophic levels - The levels that show placement on a food chain. They are:
Producer - any plant. Usually they do photosynthesis and get their energy from the sun
Primary Consumer - The species that eats the producer
Secondary Consumer - The species that eats the primary consumer
Tertiary Consumer - The species that eats the secondary consumer
Quaternary Consumer - The species that eats the tertiary consumer
After Quaternary it goes 5th order, 6th order, etc.
So I could ask questions about the food web like this:
If a human eats a trout that ate phytoplankton, what trophic level would he be?
If a human eats a trout that ate a dragonfly that ate phytoplankton, what trophic level would he be?
If the snake ate a salamander that ate a mayfly that ate phytoplankton, what trophic level would he be?
Answers:
Secondary (phytoplankton is "the grass of the sea" so it's the producer, trout is the primary consumer, the human is the secondary consumer)
Tertiary (phytoplankton is "the grass of the sea" so it's the producer, the dragonfly is the primary consumer, the trout is the secondary consumer, and the human is the tertiary consumer)
Tertiary (phytoplankton is "the grass of the sea" so it's the producer, the mayfly is the primary consumer, the salamander is the secondary consumer, and the snake is the tertiary consumer)
Energy pyramids
The energy pyramid shows how energy, numbers, and biomass(amount of living stuff) lessen as you go up a food chain. The grass at the bottom of this pyramid is more plentiful than any of the rest of what's above it. Grasshoppers are next, then voles, then owls. There are less and less as we go up the chain. This is because there isn't as much energy as we go up.
The 10% Rule states that only 10% of the energy a species has will be passed on to the next species. The other 90% is lost as heat during running, flying, growing, and other life processes are taking place. If only 10% of the original energy from the sun is passed on, there will be less and less energy for the animals further up the food chain.
In the picture it shows the grass starting with 1000 kcal (kilocalories). Only 10% is passed on to the grasshoppers. So just move the decimal place to the left once and you get 100 kcal. The voles get 10 kcal and the owl gets 1 kcal. Now, 1 kcal isn't much of anything. That's the amount of original sunlight in a snap shot of time that was passed up to the owl. He doesn't only get 1 kcal of energy from a vole. He gets more than that. We're just looking at a short period of time when the sun gave 1000 kcal to the grass (that's not much either)
The 10% Rule states that only 10% of the energy a species has will be passed on to the next species. The other 90% is lost as heat during running, flying, growing, and other life processes are taking place. If only 10% of the original energy from the sun is passed on, there will be less and less energy for the animals further up the food chain.
In the picture it shows the grass starting with 1000 kcal (kilocalories). Only 10% is passed on to the grasshoppers. So just move the decimal place to the left once and you get 100 kcal. The voles get 10 kcal and the owl gets 1 kcal. Now, 1 kcal isn't much of anything. That's the amount of original sunlight in a snap shot of time that was passed up to the owl. He doesn't only get 1 kcal of energy from a vole. He gets more than that. We're just looking at a short period of time when the sun gave 1000 kcal to the grass (that's not much either)