We don't know the longest food chain because they vary so much. There are rarely more than six links on a food chain.
What is a food chain?
A food chain is a linear diagram showing what animals eat and what their prey eats. It starts at the top with an animal that eats no other species in the chain other than the one below it in the chain and ends with a species that is eaten by no other animal in the chain except the one immediately above it.
It sounds very simple
It is simple and while useful, it is a limited tool. For example, you can apply a food chain to understand the diet of an osprey. You would say the osprey eats pike, which eats perch, which eats, shrimp. This is fine, but the osprey also eats rodents, and they aren't mentioned. A 'food web' accounts for these variations in diet and is a much more complex diagram.
How long can food chains be?
They are not precise so there is no definitive answer here. Food chains are simplifications and rarely show more than six links.
An example of a long food chain from the animal world. . .
Here's a simplified food chain with six links. You could add humans on to the end if you apply us to the term 'animal world' too.
Phytoplankton < zooplankton < fish < crab < seal < whale
Why is understanding the food chain important?
Food chains are important for ecology. They show that when you cause a change in one species, there are implications for others that are linked to it. For example, thinking about the osprey again, the bird could catch its fish in a lake. This lake suddenly changes ownership and the new owner opens it up for fishermen. They pull pike out of the water with some success. As a result, the osprey has less to eat and its numbers fall.
What is a food chain?
A food chain is a linear diagram showing what animals eat and what their prey eats. It starts at the top with an animal that eats no other species in the chain other than the one below it in the chain and ends with a species that is eaten by no other animal in the chain except the one immediately above it.
It sounds very simple
It is simple and while useful, it is a limited tool. For example, you can apply a food chain to understand the diet of an osprey. You would say the osprey eats pike, which eats perch, which eats, shrimp. This is fine, but the osprey also eats rodents, and they aren't mentioned. A 'food web' accounts for these variations in diet and is a much more complex diagram.
How long can food chains be?
They are not precise so there is no definitive answer here. Food chains are simplifications and rarely show more than six links.
An example of a long food chain from the animal world. . .
Here's a simplified food chain with six links. You could add humans on to the end if you apply us to the term 'animal world' too.
Phytoplankton < zooplankton < fish < crab < seal < whale
Why is understanding the food chain important?
Food chains are important for ecology. They show that when you cause a change in one species, there are implications for others that are linked to it. For example, thinking about the osprey again, the bird could catch its fish in a lake. This lake suddenly changes ownership and the new owner opens it up for fishermen. They pull pike out of the water with some success. As a result, the osprey has less to eat and its numbers fall.
