Introduction
During this lesson, pupils will travel thousands of miles without leaving the classroom! They will shortly be boarding the aircraft to travel to a mystery destination. You have packed their bags and need a volunteer to model the contents of the rucksack (see resources). Can the class guess where they are going? It may be to a specific country within the tropics or tropical rainforests in general.
As humans we can change what we wear to suit our environment; explain this contrast with plants. Plants have to change or adapt over time by a process of evolution to survive. The task in this lesson is to investigate how plants have adapted to suit a tropical rainforest environment.
Activities
A View from Above: With the aid of a map, ask pupils to locate where tropical forests are found. Relate this to the position of the equator, Tropic of Cancer and Capricorn. With the aid of two mind maps contrast the type of weather conditions you may encounter on landing compared to your home region. Present data on average temperature range and rainfall to illustrate the challenges faced. Explain the difference between weather and climate. Contrast the lack of seasonality in the tropics, compared to the UK.
Decision making exercise: The classroom has been transformed into a tropical rainforest with a variety of plants, pictures and a soundtrack of a forest (be as imaginative as possible). What do plants need to grow? How might they respond to the tropical rainforest climate? Are there problems associated with rapid growth and competition? Use a combination of props (such as a step ladder, candle, umbrella), pictures and plants to discuss the following adaptations; emergents, buttress roots, epiphytes, lianas, purple backed leaves on the forest floor. How do plants cope with the high humidity and rainfall? Look at drip tips and waxy surface of leaves.
Tropical rainforests can be divided into four layers (emergent, canopy, understory and forest floor); show this in image form on the whiteboard. Give pupils in pairs a worksheet showing a blank cross section of rainforest, with height labelled on the vertical axis. Label the layers of rainforest and decide which layers you are most likely to find particular adaptations in. Draw and label the adaptations.
A model plant: Ask each student to design a model plant which is ideally suited to a tropical rainforest environment. Be able to explain the thought process.
Plenary
State a plant adaptation (eg thick, waxy leaves). Ask a student to explain why this adaptation has evolved and identify a plant (or picture of a plant) that exhibits this. If successful, this student then says the name of another adaptation and nominates a fellow student to explain. Repeat the process until all adaptations have been discussed.