Task
Food chains and food webs show the flow of energy (food) through an ecosystem, offering a way to visualize who eats who in a particular environment. Most food webs begin with the Sun’s energy, which is harvested by organisms called primary producers (like grass or algae) for photosynthesis. These primary producers are the food for other organism called consumer, which depending on their predators, can be eaten by other consumers.
Food chains are linear depictions of energy flow. For instance, a simple food chain in a deciduous forest could start with the Sun, which provides the energy for the grass to grow, then the grass is eaten by grasshoppers, the mice eat the grasshoppers, and owls eat the mice. However, since most organisms eat more than one type of food and can be eaten by more than one type of predator, food webs are generally a more realistic, more complex portrayal of the energy flow in a system.
Food Chain
↑
Owl
↑
Mouse
↑
Grasshopper
↑
Grass
↑
Sun
Food Web
- trees provides energy to a caterprillars, chipmunks and deer
- caterpillars provides energy to birds
- chipmunks provide energy to owls and hawks
- deer provide energy to moquitos
- grass provides energy to rabbits, grasshoppers, and deer
- grasshoppers provide energy to mice and birds
- mice provide energy to fox, hawks, and owls
- fox provide energy to mosquitoes
- spiders provide energy to birds
- mosquitoes provide energy to spiders
- the sun provides energy to the grass
Each level of a food web or a food chain is called a trophic, or feeding, level and the organisms in the food web are classified by whether they are primary producers or consumers.
Trophic Table
| Organism | Trophic Type | Prey/Food | Predators / Grazers |
|---|---|---|---|
| Algae | primary producer | ---- | krill, fish, blue whales |
| Birds | carnivorous consumer | krill, fish | seals, killer whales |
| Blue Whales | planktivorous consumer | algae, krill | killer whales |
| Fish | omnivorous consumer | algae, krill | birds, seals, killer whales |
| Killer Whales | top consumer | blue whales, fish, birds, seals | ---- |
| Krill | herbivorous consumer | algae | fish, blue whales, birds |
| Seals | carnivorous consumer | fish | killer whales |
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