Tropical rainforests structure and adaptation

Tropical RainforestsStructure and Layers

Pg 76 to 77

Tropical Rainforests

Structure

Rainforests have a three-layer structure.

Emergent layer (50m) Canopy layer (30m) Undergrowth layer (20m)

Structure : Emergent Layer

What are they? 50m to 80m tall trees Emergent trees rise above the

canopy. They are the tallest trees in the

rainforest.How do they look like? Straight and smooth trunks. Very few branches.What are some examples? Tualang tree, Kapok tree

Kapok Tree

Tualang Tree

Structure : Canopy Layer

What are they? 20m to 30m tall trees They block 90% of the sunlight from reaching

the forest floor. They catch rain falling onto the rainforest. How do they look like? They form a continuous cover like an umbrella. They have large and waxy leaves. They grow very close to each other. What are some examples? Guava Tree, Mango Tree

Structure : Canopy Layer

Guava Tree

Structure : Canopy Layer

Lianas and epiphytes grow in the canopy.

A liana is a thick, woody vine that grow on the ground and twine up a tree to reach sunlight.

Example : Monkey Ladder Vine

Structure : Canopy Layer

An epiphyte is a plant that grows on trees to get more sunlight.

Being high up helps epiphytes spread their seeds and spores easily.

Example : Orchids, ferns, mosses and lichens.

Orchids

Bird’s Nest Fern

Moss and Lichen

Structure : Undergrowth Layer What are they? Trees are 20m and shorter It is darkest here. Sunlight is blocked by the canopy. Forest floor is wet and covered with

decomposing leaves. How do they look like? Larger and broader leaves. Small and thin. Grow far apart from each other. What are some examples? Palm tree, Fungi

Structure : Undergrowth Layer

Tropical RainforestsAdaptations

Pg 78

What is the climate like?

Tropical rainforests live in a hot and wet climate.

The temperature is high.

The rainfall is heavy.

The rainforest plants can grow all year round.

What is adaptation?

Adaptation is a word that means :

“being able to change in order to survive”

The rainforest plants adapt their features to survive in the hot and wet climate.

What are features?

Features are the different parts that make up a plant.

The features of a rainforest plant include :

Bark and branches Leaves Fruit and flowers Roots

Bark and Branches (pg 78) Adaptation Tall, straight trunks Branches are spread out.

Reason : To help the trees obtain maximum amount of sunlight.

Adaptation Smooth bark

Reason : Rainwater can flow easily from the crown to the tree roots.

Bark and Branches

Leaves (pg 78)

Adaptation Broad leaves

Reason : To get more sunlight for photosynthesis.

Adaptation Waxy, leathery or hairy leaves.

Reason : Minimise loss of water through transpiration because of the high temperature.

Leaves (pg 78)

Adaptation Leaves have drip tips.

Reason : To allow rainwater to run off easily. This stops fungi and bacteria from growing on the leaves.

Leaves

Fruit and flowers

Adaptation Colourful and strong-smelling

Reason : To attract insects and other animals to disperse their seeds and for pollination.

This is because there is no wind in the rainforest.

Fruit and flowers

Roots

Adaptation Rainforest trees have buttress roots

Reason : To support the tall tree trunks which are very heavy.

Adaptation Rainforest trees have shallow roots.

Reason : The roots are shallow because all the nutrients are found on the forest floor surface.

Water is also available on the surface so the roots do not need to dig down.

Roots