unit 2: tropical rainforests

Question 1

What are the three layers in a rainforest

Answer 1

Emergent
Canopy
Undergrowth

Question 2

Why are rainforests called ‘green lungs’?

hint: what do lungs do?

Answer 2

they absorb carbon dioxide from atmosphere and release oxygen

Question 3

List the adaptations of rainforest plants

Answer 3

• Buttress roots
• Shallow roots
• smooth bark
• Holes in leaves
• Angling of leaves
• Waxy/leathery/hairy leaves
• Drip tips
• Broad leaves

Question 4

List characteristics of the emergent layer

Answer 4

Emergent trees rise above canopy
Some 50-80 m tall
Tall, straight, smooth trunks with few branches

Question 5

define mangroves

Answer 5

a group of trees and shrubs that live in the coastal intertidal zone.

Question 6

buttress roots + their importance

Answer 6

large roots that grow 1-5m above the ground.

found on large, tall trees as they can support the trees’ heavy weight.

Question 7

functions of waxy/leathery/hairy leaves

Answer 7

• Prevent loss of moisture through transpiration due to high temperatures.
• Allow rainwater to easily run off

Question 8

characteristics of the canopy layer

Answer 8

canopy forms an almost-continuous crown by spreading their branches horizontally

Trees 20-30 m to reach for sunlight
Dense canopy catches much rain
Lianas and epiphytes grow here

Question 9

How do tropical rainforests help to maintain water supply and its quality in its vicinity?

Answer 9

tropical rainforests part of water catchment areas:

higher infiltration rates of water in forested grounds -> greater groundwater supply
Impurities trapped and filtered by soil -> clean water flows to reservoirs

Question 10

What is the function of drip tips

Answer 10

Allow water to run off easily -> prevent bacteria and fungi from growing on leaves

Question 11

Why are the roots of rainforest trees shallow

Answer 11

nutrients mostly found in the top layer of the soil (topsoil)
+
high rainfall throughout the year –> vegetation has water available all year round
=
roots need not grow deep to search for water and nutrients

Question 12

characteristics of undergrowth layer

Answer 12

• Plants have large leaves -> capture sunlight
• Usually where fungi and mosses are found.
• Vegetation is sparse as little to no sunlight can reach this layer –> plants cannot photosynthesise and make food to grow.

Question 13

how do mangrove roots adapt to their environment?

Answer 13

• Mangroves filter out salt at the roots.
• ‘Breathing’ roots that protrude from the oxygen-deprived muddy water, known as lenticels.
• Pores of roots absorb the oxygen in the air during low tide.

Question 14

State the importance of mangroves for aquatic creatures

Answer 14

Natural spawning area for fish, prawns and shellfish
Shallow and protected
Leaves & twigs decay -> release nutrients -> food for aquatic creatures

Question 15

What is the purpose of leaf angling for rainforest plants?

Answer 15

• absorb more sunlight
• avoid shading other leaves of plant

Question 16

State the importance of mangrove for coastal communities

Answer 16

Help trap sediments and extend coastal land seawards
Prevent marine erosion of coast
* Acts as a buffer for storms/waves

Question 17

How do mangrove leaves help the mangrove trees adapt to their environment

Answer 17

Excrete salt through glands in leaves

Question 18

What is the function of having holes in tropical rainforest trees’ leaves

Answer 18

Allow rainwater to easily run off
Allow sunlight to reach leaves below

Question 19

What is the function of a smooth bark on rainforest trees

Answer 19

Allow water to easily flow down to roots below

Question 20

How do mangrove trees adapt to their environment using old leaves/bark?

Answer 20

concentrate salt in old leaves or bark –> when the leaves drop or the bark sheds, the stored salt goes with them.

Question 21

What is a use of mangrove trees for village people who live near them

Answer 21

Wood used as scaffold poles & piles for Malay houses
Firewood or charcoal

Question 22

Why do plants in the rainforest have broad leaves

Answer 22

To trap as much sunlight as possible to carry out photosynthesis

Question 23

Describe the distribution of rainforests and the climate that they are in

Answer 23

Between Tropic of Cancer and Tropic of Capricorn / 25 degrees north and south of the Equator
Main areas -> Amazon Basin, Congo Basin, SEA
High average annual rainfall between 1500mm and 3000mm
High average annual temperature abt 27 degrees

Question 24

Value of mangroves as medicine

Answer 24

Ashes or bark infusions can be applied to skin disorders or sores

Question 25

Value of mangroves for non-food products

Answer 25

• fuel wood/firewood and charcoal
• bark of mangroves as tannins and dyes.
• Wood -> scaffold poles & piles for Malay houses, as it is hard & water resistant

Question 26

Environmental value of mangroves

Answer 26

protect the coast from marine erosion by absorbing the energy of storm waves and wind, and retaining the soils.
absorb pollution including heavy metals.
trap sediments, preventing the occurrence of cloudy water, which may cause corals to die.