Mid-Summative 3-4 Notes
Food Chain – sequence of organisms that eat one another in an ecosystem
Food Web – all the feeding relationships in an ecosystem
Photosynthesis – the process by which food is made in a producer (plant) by using
carbon dioxide and water in the presence of the sun
Consumer – an organism that must consume another organisms for energy (animals)
Producer – an organism that produces its own food (plants)
Decomposer – an organism that must decompose (break down) dead organisms for
energy
When using arrows in a food chain or food web, remember that the arrows represent
energy transfer. Therefore, the arrow points from the organism being eaten to the
organism doing the eating.
Consumers can be divided into levels dependent on their place in the food web. Primary
consumers producers. Secondary consumers eat primary consumers. 3rd level
consumers eat secondary consumers.
Example:
Construct a food web using the information below. Be sure to include the trophic levels
(producers, primary consumers, secondary consumers, 3rd level consumers and
decomposers).
While looking in my backyard, I made the following observations.
 I found many butterflies flying around my flowers. This must mean that the butterflies eat the
flowers.
 Ants had made several ant hills near the flowers. This must mean that the ants eat the flowers.
 Many spider webs were found near where the butterflies were flying and near the ant hills. This
must mean that spiders eat ants and spiders
 Birds were found flying near the butterflies and spiders. This must mean that birds eat
butterflies and spiders.
3rd Level
Consumers
birds
Secondary
Consumers
spiders
Primary
Consumers
Producers
ants
butterflies
flowers