Study specimen R and answer questions 4(a) to 4(c).
(a) (i) Name the phylum of specimen R. (ii) State two reasons for the answer in 4(a)(i).
(iii) State the habitat of specimen R. (b) (i) State two structural features that adapt specimen R to its habitat. (ii) State three ways in which specimen R is of economic importance.
(c) Make a drawing,8cm- 10cm long of the dorsal view of specimen R and label fully.
Study specimens S and T and answer questions 4(d) to 4(e).
(d) What type of fruits are specimens S and T?
(e) (i) State four observable differences between specimens S and T.
(ii) State three observable similarities between specimens S and T.
Explanation
(a) (i)Phylum of specimen R/Earthworm Annelida.
(ii) Reasons for the classification of specimen R/Earthworm:
-presence of metameric segmentation/segments are separated from each other (by septa) -they are bilaterally symmetrical -segments are separated from each other
-presence of chaetae - body is covered by thin collagen cuticle body is long cylindrical.
Habitat of specimen R/Earthworm: (i) -under decaying leaves -wet/moist soil -in open savanna/savannah beneath the tall grasses - in the forests in decaying tree-stumps.
(i) Features of adaptation of specimen R/Earthworm (b) -bristle-like chaetae/seatae for locomotion moist skin for gaseous exchange
-pointed anterior for burrowing into the soil slimy body reduces friction during movement
-clitellum for attachment during exchange of sperms/reproduction/ secretes cocoon (in which its legs are deposited.
(ii) Economic importance of specimen R/Earthworm -it aerates the soil -It enriches/improves soil fertility.
-its secretions neutralize the acid soil -used bait for fishing as food for some birds.
(d) Type of fruit specimen S/unripe mango fruit - Drupe
Specimen T/tomato fruit-Berry.
(c)(i) Observable differences between specimens Sand T
|
Specimen S/unripe mango fruit |
Specimen T/tomato fruit |
|
-green in colour |
red/yellow in colour |
|
one seeded |
many seeded |
|
- stony/hard endocarp |
fleshy/succulent/soft endocarp |
|
-fibrous mesocarp |
succulent mesocarp |
|
- seed large |
seed(s) small |
|
basal placentation |
axile placentation |
|
mesocarp and endocarp are fused |
mesocarp and endocarp are not fused |
Similarities between specimens S and T:
-both have seeds -both are fruits -both have three layers/epicard/mesocarp/endocarp/pericarp/ fruit wall
- coloured epicard/pericarp - both have placenta - both have thin epicard both have fleshy mesOcarp