Ecosystem Review
*An individual is one organism. (e.g. one crow)
*Population: A group of organisms of the same species living together in
one place at one time (e.g. A group of crows living in Odell Park).
*Community: All the populations of all the living things in one area.
(E.g. Odell Park is a community made up of populations of trees, crows,
mice, insects…)
A *habitat is the location (home) where an organism lives (E.g. A Frog’s
habitat is a pond.)
In a habitat an organism must find:
– Food
– Water
– Shelter
– Space
A *niche is an organism’s “job” in the ecosystem. It includes what it eats,
where it lives, and what it does. (E.g. A beaver’s niche includes chewing
bark, building dams, living in a lodge and raising a family.)
Food Chain
 A *food chain is a model that shows how energy is transferred in an
ecosystem when one organism eats another organism.
 All food chains start with the sun.
 All the energy in a food chain comes from the sun.
Food Chain Components:
Sun
Producers
Consumers
Decomposers
Examples of food chains:
1. Sun - Wheat - Grasshopper - Snake – Hawk
 *Producers are organisms that can make their own food (using sunlight,
water, air, and nutrients). E.g. Green plants and algae
 *Consumers are organisms that must eat other organisms (plants or
animals) for their food. They cannot produce their own food!
 *Decomposers are organisms that break-down the cells of dead
material and recycle the nutrients back into the ecosystem.
 Eventually all food chains end in decomposers
 A *food web is a series of interconnected food chains.