1. ECOLOGICAL NICHES
2.5
Every species interacts with other species and with its environment in a unique way.
These interactions define the ecological niche of a species, or the role of a species within its ecosystem.
An ecological niche includes what a species feeds on, what eats it, and how it behaves.
Consumers can be subdivided depending on what types of organisms they eat.
Ecological niche

2. Food Chains
2.5
Feeding relationships between species can be represented using food chains.
In a food chain, some of the chemical energy from the producer is passed along from one species to the next.
Because all organisms continually use and release energy to their environment, energy is continuously lost from all levels of the food chain.
The trophic level describes the position of an organism along a food chain.
food chains
trophic level
Species can be divided into trophic levels depending on how they obtain their energy.

3. Food Webs
2.5
Food chains are used as a tool to show simple feeding relationships.
A food web is a more accurate, but still incomplete, way to illustrate feeding relationships.
Complex food webs are usually more stable than simple food webs, because species do not depend on just one source of food.
food web