AIMS :

To know that the soil is :

 a particular environment made of materials from underground rocks and remnants of living beings.

 the living environment of a large variety of small animals and mushrooms.

 To know that these living beings play an essential role in the making of the soil, by ensuring the decomposition of its litter.

METHODICAL AIMS :

To extract living beings from the ground with tools such as a Berlese funnel

To Observe and identify the various components of the soil.

EQUIPMENT

Berlese funnel

Test tubes.

Lumps of earth.

Earth wildlife collected during a outing.

UNFOLDING

Work with the following pupils’ activity sheet :

1) Take samples

Take samples from the litter and the soil during an outing. Draw a section schema of the soil to be observed, placing the main components of the soil (underground, ground, litter of dead leaves brown humus layer, ochre-brown layer)

2) Observe and classify the animals .

Collect living beings from the ground thanks to a Berlese funnel. [1].

Thanks to the classification grid (see “life in the garden. How to classify animals�� ?), find which group they belong to and write it down in each box.

More than 2cm long earthworm Centipedes 12 to 15 mm Smaller than 2mm dust mites Ground beetle 25 to 30 mm Collembola 1,5 mm

Eats leaves Eats vegetal debris Eats vegetal debris Eats insects ad larva Eats vegetal debris

3 Determine the role of these animals..

Read the following text :

“ In the Autumn, the ground of the forests is covered with fallen leaves. Yet, as years go by, the thickness of the layer of leaves doesn’t increase.�� ?

Work with the included photographs, which shows the work of the earthworms.

Thses documents show the section of the same piece of soil,

A ) before the earthworms have come,

B ) one or two months after their passage.

Propose a explanation to the sentences read in the text.

Doc. A Doc. B

ASSESSMENT

It will check the pupils’ ability to :

 place the various layers of the ground on a schema,

 determine the role of wildlife in the formation of the soil

 be able to use classification key.

[1] A device mainly composed of a sieve and a source of light, permitting to collect the micro wildlife from the ground.

Jean-Michel Josse, Biology teacher at Secondary School Maximilien Robespierre Goussainville Val d’Oise France