NOTIONAL OBJECTIVES :

Pre-required : chlorophyll plants feed on minerals, animals feed on other living beings and minerals.

The children have to learn that each living being produces its own matter using the one it takes from the environment. The chlorophyll plants are primary producers. All the other living beings are secondary producers.

METHOD OBJECTIVES :

 to take measures of the mass and size increase to illustrate the matter production idea.
 to understand information from a text
 to make a chart from data displayed in a table

MATERIALS :

 Slices of wood cut in stumps or trunks (on which you can number the rings)
 Graduated paper

PROCEDURES :

Use the following worksheet :

A. The chlorophyll plants are primary producers

Read the following text :

“An oak, like all trees, is born, grows, breeds, and dies. During its life, it produces wood, but leaves and acorn as well.

1- The foresters can measure regularly the height and diameter of the oak : hence, they supervise its layer growth…

2- During its life an oak produces wood but what else does it produce ?

3- How do you call this new matter ?

4- According to you, what does it produce this new matter from ?

5- Using information from the text, give a title to the chart below and explain how you found it.

With the help of the chart complete the table 1-2-3

6- How does the height of this tree develop ?

7- “When a forester cuts a trunk, he can see the rings corresponding to the layer growth of the tree. Each ring is a wood layer composed of a clear and a dark section (see schema below). A ring corresponds to one year growth.

Observe the growth rings on a trunk slice (cf. distributed material). Do they have the same thickness ? What can you deduce ?

8- With a ruler, measure the thickness growth of the tree and complete the following table with these measures :

How does the size increase of this tree evolve ?

B. The animals produce matter as well

1. Recall what substances animals take from their environment and how they are called.

2. Study an animal production, for example the boar, from the following sheet :

A boar has been regularly weighed from its birth till aged 12 months. The results of these measures have been noted in the table below :

9- How does the boar’s mass develop ?

Draw, on a sheet of graduated paper, the boar growth curve, by writing out

 on the horizontal axis, 1 cm for 2 months
 on the vertical axis, 1 cm for 10 kg

ASSESSMENT :

Capacity for the pupil to remember the following summary :

We showed the plants and animals increase their height and mass by producing matter. Among plants, this matter is produced from minerals. They are primary producers. On the other hand, among animals, this matter is produced from other living beings and minerals. These animals are called secondary producers.

Jean-Michel Josse professeur de Sciences de la Vie et de la Terre, Lycée Français Charlemagne de Pointe Noire, Congo Brazzaville