Study specimens A, B and C carefully and use them to answer questions (a) to (d).
(a) State the habitats specimens A, Band C.
(b) State (i) two observable features each of specimens A,B and C.
(ii) how the features in 1(b)(i) adapt the specimens to their habitats.
(c) State three Observable differences between specimens A and C.
(d) Make a drawing 8- 10cm long of specimen C and label Tully.
Explanation
(a) Habitats of specimens A, B and C: A/Water lettuce - On the surface of ponds/lakes/streams.
B/Cactus-Deserts/savannahs/dry/arid regions/along the sea coast.
C/Talinum- Farmland/gardens/wet lands/waste land/any other appropriate habitat.
(b)(i) Observable features: A/Water lettuce-Broad aerial leaves- Numerous adventitious roots - Leaves and stem green Slender stem/stolon -Hairs on surface of leaves -Rosette arrangement of leaves -Spongy leaves. B/cactus - Leaves modified into spines-Succulent stems- Thick waxy cuticle on stems- are green/chlorophyllous - Flattened stem.
C/Water leaf/Talinum sp/Amarantus sp-Well developed root/taproot system - Numerous green leaves - Erect stem-Swollen taproot (for Talinum sp).
(c) Observable features of A, B and C: A/Water lettuce - Broad aerial leaves/rosette arrangement of leaves makes it buoyant/receive maximum sunlight for photosynthesis - Numerous adventitious roots/root hairs for absorption of water and mineral salts/aids floatation
- Leaves and green/chlorophyll for photosynthesis
-Slender stem/stolon that offer minimum resistance to water currents
-Hairs on surface of leaves prevent water from blocking stomata/aiding photosynthesis/respiration Buds on stem/stolon for vegetative propagation
- Spongy leaves aid buoyancy. B/Cactus-Flattened stems to receive maximum light
- Leaves modified into spines to prevent water loss
- Succulent stems for water storage
- Possession of thick waxy cuticle on stem to reduce water loss by transpiration.
- Stems are green/chlorophyllous for photosynthesis.
C/Water leaf/Talinum sp/Amarantus sp
- Well developed root/taproot system for anchorage and water absorption
- Possession of numerous green leaves for photosynthesis
- erect stem hold the leaves to receive maximum sunlight.
-Talinum has swollen taproot for storage.
c) Observable differences between A & C:
|
A/Water lettuce |
C/Talinum sp/Waterleaf/Amarantus sp |
|
Adventitious root system |
Tap root system |
|
Horizontal stem/stolon |
Erect stem |
|
Hairs on leaves |
Hairless leaves/smooth surface |
|
Leaves borne in a rosette |
Leaves arise singly on the stem |
|
Absence of branches |
Branches present |
|
Flowers absent |
Flowers present |
(d) Drawing of specimen C/Talinum sp/Amaranthus sp:-Prominent taproot
