Sec 1 Unit 3

Lesson 1

Tropical Rainforest

At the end of the lesson you will be able to :

1.Identify a tropical rainforest 2.List the characteristics of a

tropical rainforest

3.Label and describe the layers of a tropical rainforest.

How can we save tropical rainforest?◦ What are tropical rainforests?

◦ What is deforestation?

◦ Where are tropical rainforests found?

◦ Which areas have been deforested?

◦ Why do we deforest?

◦ How should we manage deforestation?

Take 2 minutes, read the poem

Lets listen to a rainforest.

Earth’s oldest ecosystem.

High rainfall and high temperatures throughout the year.

Thick, luxuriant evergreen forests.◦ Evergreen = no distinct shedding season.

1. Diversity of types

2. Structure of rainforest

3. Plant Adaptations

Highest plant diversity in all forest types.

Warm temperatures and constant rainfall encourages plant growth.

Over 300 species in 0.01sq km

Source of common local food◦ Bananas, mangoes, pepper, cinnamon, corn, pandan, walnuts

Plants grown to different heights

Three-layered structure found in tropical rainforests

Trees up to 50m talls.Clearly visible from above Trees that rise above the even canopy below.

Trees tend to have tall, straight and smooth trunks.

Tualang, Kapok tree.

Layer of trees that grow to between 20 – 30m

The crowns form an interlocking layer.

Blocks 90% of sunlight from the forest floor.

Deflects most rainfall.

Dark most of the day as sun rays are blocked by canopy.Plants tend to be small and widely-spaced apart.Vegetation is sparse on forest floor, mostly decomposing leaves.

Epiphytes grow on trees to receive more sunlight.◦Ferns, orchids, mosses

Lianas are woody vines that twine up trees for more sunlight.◦Monkey ladder vine

50m

20m

Emergent layer

Canopy layer

Epiphytes

Lianas

Buttress Roots

Ferns

Plants adapt to the climatic conditions with special features.

Without adaptations, they will not survive the high temperatures and heavy rainfall.

PG 78

Tall straight trunks

Branches spread out near the top to reach for sunlight.

Smooth bark to allow rainwater to flow easily down to the roots.

Broad leaves to capture more sunlight

Waxy, leathery or hairy surfaces to minimise water loss.

Drip tips to allow water to runoff.◦ Reduces the growth of fungi and bacteria

Drip tip

Waxy surface

Hairy surface

Still air and lack of wind is bad for seed dispersal.

Strong smelling flowers and fruit encourage animal and insect pollination.

http://www.youtube.com/watch?v=cm36-UKx5EY

Large spread roots that grow up to 5m above the ground.◦ Help to support the tall emergent and

canopy trees

Shallow roots that reach for the nutrients in the topsoil and decomposing foliage.

Constant presence of water, no need for deep roots that search for ground water.

By the next lesson, pick a leaf that you think is from a rainforest tree and sketch it on a piece of blank paper.

Submit both the leaf and the paper as your homework.

Complete the test in the time allocated.

Remember to write in black ink.

If you are drawing diagrams, you can use pencil.