Topic: Food chain

Author: Leokadia Stalewicz

Target group

8th‑grade students of elementary school

Core curriculum

General requirements

I. Knowledge of biological diversity and basic biological phenomena and processes. Student:

3. presents and explains the relationship between the organism and the environment.

Specific requirements

VII. Ecology and environmental protection. Student:

6. analyzes the nutritional dependencies (food chains and trophic networks), constructs simple food chains (chains of joining) and analyzes the presented (in the form of a diagram) networks and food chains.

General aim of education

You will learn what food dependencies bind organisms in the ecosystem.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• to categorize organisms in the food chains..

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • exposition.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Before classes

• Students get acquainted with the content of the abstract. They prepare to work on the lesson in such a way to be able to summarize the material read in their own words and solve the tasks themselves.

Introduction

• The teacher explains the aim of the lesson and together with students determines the success criteria to be achieved.

• Then he writes the subject of the lesson on the blackboard or interactive whiteboard. Students write it in notebooks.

Realization

• The teacher asks students to read the abstract themselves, paying particular attention to the illustrations.

• Based on the resources from the „Food Chain” lesson, the teacher explains to students the meaning of the concept of trophic (digestive) chain. Together with students, it analyzes examples of food chains included in the lesson and explains the role of individual organisms in these chains.

• Working in groups, students analyze the food network presented in the „Food network” illustration and then execute the Task 1. in this lesson. The teacher indicates the person who will present the correct solution. The other students supplement the answer if necessary.

• Students carry out the interactive exercises checking the level of knowledge learned during the lesson. The teacher initiates a discussion during which the correct solutions for all the exercises performed by the students are discussed.

Summary

• The teacher chooses one student by random method and asks him or her to explain in own words the meaning of a given word or concept learned during the lesson.

Homework

• Write a short note about the topics covered in the lesson.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Food chain

Organisms in ecosystems are interrelated with food dependencies in such a way that they form food chains. In the food chain, the species that is one link in the chain becomes the food of the species being next link in the chain.

The food chain (also referred to as trophic) begins with the producer. The next link in the chain is the first level consumer eating the producer, i.e. herbivore. The next link is a carnivore, i.e. a second level consumer, followed by a third level consumer and possibly other consumers. The place that a given organism has in the food chain depends on what it feeds itself and for what organisms it becomes food. We call this a trophic level.

The arrows used in the food chain illustrate the flow of matter and energy through the trophic levels. These arrows run from producers who create organic compounds from inorganic compounds to consumers. Species, especially omnivorous, may take different trophic levels in different food chains, depending on what is their primary source of food.

In the first food chain, the producer is a potato, a first level consumer Colorado beetles, a second level consumer is a pheasant, and, finally, a fox is the third level consumer. This chain is longer than the next one, in which the last link – fox – is the second level consumer. This is due to the fact that the pheasant is an omnivorous bird – it may appear in the food chain both as a herbivore (when feeding on wheat) or as a carnivore (when feeding on a herbivorous Colorado beetles). Potatoes can be food for mice that are eaten by foxes, buzzards or kestrels. On the other hand, not only the pheasant, but also partridge and robin feed on the Colorado beetles. The same organisms often occur simultaneously in several food chains that are all connected and form trophic networks. The richer and more diverse the ecosystem, the more complex the food chains are.

Some food chains are very short while other are long. An example of a very short food chain is that of an elephant. Elephant is the consumer of the first level and also of the last one. Due to its size, it rarely becomes prey.

Examples of extremely long food chains are found in some aquatic ecosystems, inhabited by many species.

• All organisms in the ecosystem are connected by complex food dependencies – they form chains and trophic networks.

• The trophic levels are distinguished in the ecosystem: producers, consumers of the first, second and subsequent levels and decomposers.