As students observe a terrarium or aquarium, have them identify the living and nonliving components on a class T-chart. One example that students might observe in an aquarium is a fish hiding between two rocks in order to protect itself from another fish. Many aquariums also have a bubbler which adds oxygen to the water. If the aquarium students are observing has a bubbler, they might recognize that the fish interact with oxygen being provided by the bubbler and use it to breathe. An example of an interaction students might observe in a terrarium is a lizard sunbathing on a rock under the heat lamp. The lizard is using the warmth from the lamp and the rock to maintain a healthy body temperature. 

Have students pair up and choose a component from both the living and nonliving list that interact and describe the interaction. In their notebooks, have students draw and label their chosen components, then write a sentence explaining how the components interact and how the living component depends on the non-living component. Students will mix-pair-share their chosen components and explanations.

An example of a food chain in words and in images is provided below

A food chain arranges the organisms in an ecological community according to the order of predation in which each uses the previous member as a food source; may include producers, herbivores, omnivores, and carnivores.  As an educator, it is important to know that herbivores, omnivores, and carnivores are all referred to as consumers at this grade level.