food chains

Living organisms need energy to survive. A food chain sequences where this energy comes from and where it goes to. Natural food chains evolve over long periods of time, but if you introduce a new energy source to an existing population, you can create a new food chain. For example, if you introduced a plant in your garden that attracted aphids, you might quickly find ladybirds arriving to feed on the aphids and then birds who might feed on the ladybirds and so on.