a. Classify the following biological associations under the headings in the table below:
(i) Remora and shark;
(ii) Lichen;
(iii) Cattle and white Egret;
(iv) Tapeworm in the gut of humans;
(v) Flowers and Honeybees;
(vi) Mistletoe and Cacao plant.
| Parasitism | Mutualism | Commensalism |
[6 marks]
b. (i) State three adaptive features of parasites. [6 marks]
(ii) State two effects of parasites on their hosts. [2 marks]
c. (i) What are saprophytes? [2 marks]
(ii) Give four examples of saprophytes. [4 marks]
Use the information below to answer questions (a)(i) and (a)(ii).
Hb Are presents normal haemoglobin,
HbS represents sickled haemoglobin.
a. A female heterozygote for sickle cell married a sickler. With the aid of a genetic diagram, determine the:
(i) possible genotypes of their offspring; [8 marks]
(ii) phenotypic ratio of the offspring. [2 marks]
b. Explain briefly the reason why a Rhesus negative woman married to a Rhesus positive man might lose her second pregnancy. [5 marks]
c. Name two examples of features in animals that support the theory of use and disuse of body parts as used by Lamarck. [2 marks]
d. List three structures in mammals that are vestigial. [3 marks]
a. Explain briefly the importance of the following factors and organisms in the nitrogen cycle
(i) lightning; [3 marks]
(ii) Nitrosomonas; [2 marks]
(iii) Azotobacter. [2 marks]
b. Name the excretory organ in:
(i) insects: [1 mark]
(ii) earthworm.
c. Define
(i) hepatitis; [4 marks]
(ii) kidney stones [4marks]
d. (i) State three effects of lack of sense receptors in the skin to humans. [3 marks]
(ii) List three layers of the epidermis in the skin of humans. [3 marks]
e. (i) What is metamorphosis? [2 marks]
(ii) State the type of metamorphosis exhibited by each of the following insects listed in the table below.
| Insect | Type of metamorphosis |
| Grasshopper | |
| Cockroach | |
| Butterfly | |
| Mosquito | |
| Housefly |
a. Complete the table below.
|
Organism |
Mode of feeding |
Feature of mouthpart that adapts organism to mode of feeding |
[6 marks]
b. List five parts of the alimentary canal of an earthworm. [5 marks]
c. State six ways by which water could be polluted by agricultural practices. [6 marks]
d. Describe briefly the life cycle of a housefly. [5 marks]
e. Make a diagram, 6 cm – 8 cm long of the hypogeal germination in a mature maize seedling and label fully. [8 marks]
The hormone which regulates the amount of glucose in the blood is called?
