TEST OF PRACTICAL KNOWLEDGE QUESTION (a)(i) Specimen A is a flower. Remove all the stamens and three petals from specimen A leaving the special petal. Make ...
(a)(i) Specimen A is a flower. Remove all the stamens and three petals from specimen A leaving the special petal.
Make a drawing 10-12cm long of the remaining parts of specimen A and label fully.
(ii) what type of ovary is present in specimen A?
(ii) Give one reason for your answer in 1(a) (i) above.
(iv) Describe the petals and sepals of specimen A.
(v) What is the function of the special petal?
(vi) State three features of specimen A which have led to the success of flowering plants.
(b)(i) What type of fruit is specimen B?
(ii) Give two other examples of the fruit type.
(iil) State the mode of dispersal of specimen B.
(iv) State two biological importance of the class of fruit to which specimen B belongs.
(a)(i) Drawing of the remaining parts of Specimen A
After removing all the stamens and three of the petals from the papilionaceous flower (Specimen A) and leaving only the special (standard) petal, the remaining parts are the calyx, the single standard petal, the gynoecium (ovary, style and stigma) borne on the receptacle, and the flower stalk. A drawing 10 to 12 cm long of these parts, fully labelled, is shown below.
Specimen A with the stamens and three petals removed: the standard petal, calyx, and superior gynoecium (ovary, style, stigma) borne on the receptacle. Drawn 10 to 12 cm long and fully labelled.
(a)(ii) Type of ovary
Superior ovary.
(a)(iii) Reason
The ovary is located at a higher position than the receptacle; that is, it sits on top of the receptacle, above the point of attachment of the other floral parts (the sepals and petals).
(a)(iv) Description of the petals and sepals of Specimen A
The sepals are of the same colour as the petals (petaloid) and are smaller than the petals in size.
One of the sepals is keel-shaped.
The petals are fan-shaped and brightly coloured.
The special (standard) petal is tubular and flat, bearing guide marks.
(a)(v) Function of the special petal
The large, brightly coloured standard petal guides the visiting insect (bee) to the nectar, acting as an advertisement and landing platform that promotes cross-pollination.
(a)(vi) Three features of Specimen A responsible for the success of flowering plants
Brightly coloured petals which attract insects that pollinate the flower.
Large petals which are easily seen by the pollinating insects.
Presence of nectar which attracts insects and enhances cross-pollination, leading to variation and survival of the species.
(Sticky stigma to hold pollen grains, and sticky, rough pollen grains that attach to insects, are further pollination-ensuring features.)
(b)(i) Type of fruit (Specimen B)
A legume (pod).
(b)(ii) Two other examples of the fruit type
Bean and pea (others include Crotalaria, Caesalpinia, Delonix sp. and Mucuna).
(b)(iii) Mode of dispersal of Specimen B
By an explosive (self) mechanism, in which the dry pod splits open suddenly along its two sutures and flings out the seeds.
(b)(iv) Two biological importances of legumes
They are a source of food and protein (and feed for livestock).
They fix nitrogen in their root nodules, enriching the soil (they also serve as cover crops that check erosion).
(a)(i) Drawing of the remaining parts of Specimen A
After removing all the stamens and three of the petals from the papilionaceous flower (Specimen A) and leaving only the special (standard) petal, the remaining parts are the calyx, the single standard petal, the gynoecium (ovary, style and stigma) borne on the receptacle, and the flower stalk. A drawing 10 to 12 cm long of these parts, fully labelled, is shown below.
Specimen A with the stamens and three petals removed: the standard petal, calyx, and superior gynoecium (ovary, style, stigma) borne on the receptacle. Drawn 10 to 12 cm long and fully labelled.
(a)(ii) Type of ovary
Superior ovary.
(a)(iii) Reason
The ovary is located at a higher position than the receptacle; that is, it sits on top of the receptacle, above the point of attachment of the other floral parts (the sepals and petals).
(a)(iv) Description of the petals and sepals of Specimen A
The sepals are of the same colour as the petals (petaloid) and are smaller than the petals in size.
One of the sepals is keel-shaped.
The petals are fan-shaped and brightly coloured.
The special (standard) petal is tubular and flat, bearing guide marks.
(a)(v) Function of the special petal
The large, brightly coloured standard petal guides the visiting insect (bee) to the nectar, acting as an advertisement and landing platform that promotes cross-pollination.
(a)(vi) Three features of Specimen A responsible for the success of flowering plants
Brightly coloured petals which attract insects that pollinate the flower.
Large petals which are easily seen by the pollinating insects.
Presence of nectar which attracts insects and enhances cross-pollination, leading to variation and survival of the species.
(Sticky stigma to hold pollen grains, and sticky, rough pollen grains that attach to insects, are further pollination-ensuring features.)
(b)(i) Type of fruit (Specimen B)
A legume (pod).
(b)(ii) Two other examples of the fruit type
Bean and pea (others include Crotalaria, Caesalpinia, Delonix sp. and Mucuna).
(b)(iii) Mode of dispersal of Specimen B
By an explosive (self) mechanism, in which the dry pod splits open suddenly along its two sutures and flings out the seeds.
(b)(iv) Two biological importances of legumes
They are a source of food and protein (and feed for livestock).
They fix nitrogen in their root nodules, enriching the soil (they also serve as cover crops that check erosion).
