Food chains and food webs Flashcards
What is a food chain?
A food chain shows the transfer from one organism to the next.
Where does a food chain start?
A food chain starts at a producer.
How is energy transferred between organisms in a food chain?
Energy is transferred by ingestion!
Construct a simple freshwater food chain
Algae (producer) - water fleas (primary consumer-herbivore) - guppy (secondary consumer-carnivore) - bass (another secondary consumer) - green heron (tertiary consumer/top carnivore)
Construct a simple seashore food chain
Algae on rocks - limpets - crabs - gull
What is a tropic level?
The position of an organism in a food chain, food web, pyramid of numbers or pyramid of biomass.
Wait a sec… Apparently the transfer of energy for one tropic level to another is inefficient. Why is it inefficient??
Because the amount of energy that is passed on in a food chain is reduced at every step.
Why do food chains usually have fewer than five tropic levels?
Because the longer the chain, the more energy is lost as heat.
Why is it more efficient for humans to eat plants than to feed livestock plants and then eat the livestock?
Because the fewer tropic levels, the less energy is lost. We would receive more energy from eating the plants than eating the animals that eat the plants.
Wow, a food web, that sounds complicated, what is it?
A food web is essentially a bunch of food chains knitted together. Or, in professional terms; a network of interconnected food chains.
Producer
An organism that makes it’s own organic nutrients, usually using energy from sunlight, through photosynthesis.
Consumer
An organism that gets its energy by feeding on other organisms.
What are the three levels of consumers in a food chain?
Primary, secondary and tertiary.
Herbivore
An animal that gets its energy by eating other plants.
Carnivore
An animal that gets its energy by eating other animals.
