Y2 Geography: Tropical Rainforests

Adaptations, Characteristics, Benefits

Name the 5 layers of the rainforest from top to bottom, and describe the characteristic of each layer.

• Emergent layer

  • 40m - up to 60m tall

  • Mushroom-shaped crowns

• Canopy layer

  • 20m - 30m tall

  • Umbrella-shaped crowns that form a continuous canopy

• Understorey layer

  • 5 - 15m tall

• Shrub layer

  • 10m tall

• Forest floor

  • 0m

  • sparse vegetation due to very little sunlight reaching the forest floor

Where are rainforests found? Include latitudes, tropics, percentage covering world, and largest rainforest

• Found along the Equator (e.g. South America, Central Africa, South-east Asia), between the latitudes of 23.5ºN and 23.5ºS

• Between the Tropic of Cancer and Tropic of Capricorn

• they cover 6% of the world’s surface

• The largest rainforest is Amazon

What is the climate of the rainforest? Include physical conditions, temperature, and rainfall

• Warm and wet all year round, little daily or seasonal variation

• 27ºC on average

• 2,500mm + rainfall (high total precipitation)

Where can water be found in the rainforest?

can be found from e huge rivers that run throng the rainforest

Describe the vegetation and biodiversity in the rainforest.

• Dense and lush - the hot and wet climate encourages rapid plant growth 

• Very tall trees

• High levels of biodiversity

  • more than ⅔ of global plants species and over ½ of the world’s animals

• evergreen

State three characteristics of the soil in the rainforest.

• several metres thick

• red in colour (rich in iron)

• nutrient-poor

  • nutrients are not stored in the soil for very long. The heavy rains that occur in rainforests wash organic material from the soil, also known as ‘leaching’

  • nutrients released by decomposition are taken up quickly by the plants, instead of being stored in the soil

  • many of the dead, fallen leaves and other organic matter are swept away before releasing all of their nutrients

State three adaptations of trees in the rainforest.

• branches and leaves are found at the top one third of the tree

• Have tall tree trunks

• Have thin bark

Why do trees have branches and leaves at their top one third?

• to obtain the maximum sunlight for photosynthesis

• The rainforest is very dense and lush, with many plants fighting to get the most sunlight

• By having branches and leaves at the top one third, this maximises the amount of sunlight for maximum photosynthesis to ensure a higher chance of survival for the plant

Why do trees have a tall and thin tree trunk?

• allow trees to reach sunlight

• rainforest is very dense and lush

• little sunlight in the rainforest, so having a tall and thin trunk allows for the tree to grow taller than the other trees to get the most sunlight

Why do trees have smooth bark?

• when it rains, it allows water to flow down to the roots easily

Why do trees have thin bark?

• no need for protection against cold, dry weather

What are the adaptations of leaves in the rainforest?

• drip tips

• Broad and green

• Thick and leathery

• Smooth and waxy

Why do leaves have drip tips?

• drip tips are pointy tips

• Allow excess water to drip off so that the leaf surface is kept dry

• Prevents growth of mould and plant diseases

Why are leaves broad and green?

• larger surface area to capture more sunlight and maximise photosynthesis

Why are leaves thick and leathery?

• withstand heat

• Reduce moisture loss

Why are leaves smooth and waxy?

• so rainwater can flow off easily

• Prevents mould and prevents plant diseases

Name one adaptation of flowers in the rainforest, and explain why.

• Colourful flowers and sweet-smelling fruits

• Attract insects and birds to aid in pollination

• Why? The air is generally still due to the dense nature of the forest so flowers do not generally get pollinated by wind, etc.

What is one adaptation of special plants in general in the rainforest? Explain how they function and why they need to adapt.

• carnivorous

  • E.g. tropical pitcher plants, meat eating plants

  • Attract insects using smelly nectar and trap them

  • why? → rainforest soils lack nutrients, so these plants get their nutrients from the insects they trap and digest

Name two types of roots and how they function/adapt.

• shallow roots

  • Do not go deep into the soil

  • Water is readily available at the surface and provides much moisture in the topsoil, and not many nutrients are found apart from in the topsoil

• Buttress roots

  • Broader base

  • There are many tall and heavy trees so this helps to support heavy weight of tall trees

What is a liana? Elaborate on where it can be found, its characteristics, and what it does to adapt.

• can be found in canopy and understorey layers

• Thick woody vines that grow in the ground and twine up the trees for sunlight

• Can spread from tree to tree to get as much sunlight a possible

What are epiphytes? Include examples of epiphytes, where they can be found, and how they adapt.

• e.g. ferns and orchids

• Can be found in canopy and understorey layers, grow high up on tree trunks and branches

• Roots hanging in the air

• They make their own food

• Non-parasitic plants

What are bromeliads? (Enrichment?)

• have a central funnel of leaves for collecting and storing water

• water pools are used by some frogs to rear their young

What are saprophytes? (Enrichment?)

• fungus or microorganism that lives on dead or decaying organic matter