A biology lesson on deforestation

Objectives of the lesson Content objective: Students should be able to define deforestation, identify its causes, and describe and explain its effects. Language objective: To write paragraphs explaining the effects of deforestation. (Use the language form of causal explanation.)

Teaching sequence Activity1: Distinguish Definition, Causes and Consequences. Activity2:Work out the causal relationship in the first Activity2: Work out the causal relationship in the first consequence: consequence: Destruction of natural habitats in the forest. Destruction of natural habitats in the forest. Activity3:Work out the causal relationship in the second Activity3: Work out the causal relationship in the second consequence: consequence: increase in carbon dioxide concentration in the atm. increase in carbon dioxide concentration in the atm. Activity4:Work out the causal relationship in the third Activity4: Work out the causal relationship in the third consequence: consequence: Soil erosion. Soil erosion.

Activity 1 Distinguish Definition, Causes and Consequences.

Getting wood to make paper Soil erosion Removing too many trees from forest Destruction of natural habitats Building leisure resorts Getting wood to make furniture Building houses and roads Increase in carbon dioxide in atmosphere

Getting wood to make paper [cause] Soil erosion [consequence] Removing too many trees from forest [definition] Destruction of natural habitats [consequence] Building leisure resorts [cause] Getting wood to make furniture [cause] Building houses and roads [cause] Increase in carbon dioxide in atmosphere [consequence]

Activity 2 Work out the causal relationship in the first consequence: Destruction of natural habitats in the forest.

Cutting down of trees Loss of home for wildlife [Possible] extinction of wildlife species in forest Destruction of natural habitats

Activity 3 Work out the causal relationship in the second consequence: Increase in carbon dioxide concentration in the atmosphere

Less CO2 is absorbed Cutting down trees Fewer plants undergo photo- synthesis Concentration of CO2 in atmosphere rises

Activity 4 Work out the causal relationship in the third consequence: Soil erosion

Cutting down of trees flooding Soil erosion Top soil is washed away to rivers by rain Removal of protection soil is blown away by wind Land may become a desert Loss of agricultural land