UNIT 1: ECOSYSTEMS- 4th grade (II)

Food chains and food webs

One of the most important relationships between living things in an ecosystem involves energy. Every organism needs energy in order to live. Energy moves through an ecosystem through food chains and food webs. All food chains begin with energy from the SUN.

Food chain is the feeding relationships from one organism to another in an ecosystem.

Food chain has different levels:

·         Producer.

·         Herbivores (primary consumers).

·         Carnivores (secondary consumers).

·         Decomposers.

When one type of organism eats another, energy is passed from one level to another.

-Producers: use energy from the Sun to make their own food and act as a source of food for other organisms in an ecosystem.

-Consumers: obtain their energy by eating other living things. Herbivores- an animal that eats plants (grasshopper, cricket) the most number of insects are herbivores and there are big animals like giraffe, koala and the elephant. The energy from plants is eaten and used by herbivores. 1^st level Consumer-Herbivores.

Carnivores- 2^nd level Consumer, an animal that eats meat, lizard, dog, cat, and wolf. And there are other animals like the owl, lion and the tiger that are the 3^rd level of Consumers and they are carnivores.

Third level Consumers eat Second Level Consumers

Animals that hunt and eat other animals are called predators; the animals that predators eat are called prey.

-Decomposers: are organisms that break down dead plants or animal matter and release the nutrients back into the soil. Decomposer such as bacteria, fungus and worms transfer energy to soil to make plants.

A food chain shows the feeding relationship between organisms and ecosystem.

Organisms are dependent on each other within a food chain.