Geography S1 Chapter 5 (remaining parts of 114&115 from part 1 until 117)

Question 1

description of low tide level (1)

Answer 1

lower-lying parts of the coast, which are close to the low tide level, are flooded for longer period of time by the tide compared to areas which are further inland and closer to the high tide level

Question 2

description of low tide level (2)

Answer 2

mangrove plant species that are able to tolerate higher salinity levels are longer period of flooding are thus found closest to the low tide level

Question 3

what are the groups of species typically found in Southeast Asian mangrove forests?

Answer 3

Sonneratia and Avicennia

Question 4

what groups of species are not as tolerant of conditions stated in information?

Answer 4

Rhizophora and Bruguiera

Question 5

Description of Rhizophora and Bruguiera

Answer 5

Usually found closer to the high tide level instead, where the duration of flooding by the tide is shorter

Question 6

what adaptations that mangrove plants have developed to help them survive in the saline water of the coastal environment?

Answer 6

1. salt- secreting leaves
2. salt-excluding roots
3. aerial roots

Question 6

what do salt-secreting leaves enable mangrove plants to do?

Answer 6

remove salt from the saline water that their roots have absorbed

Question 7

what happens after the concentrated salt-solution secreted by the leaves evaporate?

Answer 7

salt crystals are left behind on the leaf surface and are subsequently removed by rain or wind

Question 8

what do the leaves of certain mangrove species that are unable to secrete salt through their leaves do? (eg: sonneratia)

Answer 8

they deposit excess salt in older leaves which they eventually shed.
-helps to prevent the salt form building up within the plant

Question 9

what is the mangrove species which deny the intake of salt using their roots called?

Answer 9

salt-excluding species (eg: Bruguiera mangrove plant)

Question 9

what happens to the soil found in the coastal environment?

Answer 9

it is flooded for several hours of the day by tide

Question 10

what do salt-excluding species have?

Answer 10

roots which prevent salt from entering

Question 11

what happens to the soil found in the coastal environment as it is flooded for several hours of the day by tide?

Answer 11

waterlogged, very poor in oxygen, soft & unstable

Question 12

what have mangrove plants developed to help adapt to the soil conditions?

Answer 12

aerial roots

Question 12

What is the first function of aerial roots?

Answer 12

1. all grow partially above soil surface enabling them to take in oxygen directly from the air when they are exposed during low tide.
   -helps them to survive in oxygen-poor soil

Question 13

What is the second function of aerial roots?

Answer 13

2. help to anchor the mangrove plants to the soft soil, thus preventing them from being uprooted and washed away by strong waves

Question 14

first type of aerial roots

Answer 14

1. pencil roots
   -avicennia & sonneratia
   -grow vertically upwards from main roots found just below soil surface
   -slender appearance
   -can grow up to 20cm tall

Question 15

2nd type of aerial roots

Answer 15

2. cone roots
   -sonneratia
   -thicker
   -conical appearance
   -grow up to 1.5m

Question 16

4th type of aerial roots

Answer 16

4. knee-bend roots
   -bruguiera
   -(1)bend upwards to emerge above the soil surface
   -(2)bends downwards into the soil at regular intervals.

Question 17

3rd type of aerial roots

Answer 17

3. prop roots
   -rhizophora
   -grow from the trunk & lower branches toward the ground
   -helps the plant breathe & provide it with support as they for a broader base around it