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]
Explanation
| Parasitism | Mutualism | Commensalism |
|
Tapeworm in the gut of humans |
Lichen Cattle and white Egret Flowers and Honeybees |
Remora and shark |
b. (i) Adaptive features of parasites
- possession of specialised organs/haustoria/suckers/hooks; for attachment to the surface of the body of the host;
- specialised piercing/sucking mouthparts; for sucking fluids/blood/plant juices;
- hermaphrodite/ability to reproduce rapidly/easily in large numbers/large quantity of eggs are produced; to propagate their lineage/species;
- large surface area; for absorption of digested food;
- possession of special features/structures/cuticle; to withstand harsh environment/conditions/being digested.
(ii) Effects of parasites on their host
Absorption of nutrients from the body of the host can:
- lead to stunted growth;
- lead to low resistance to diseases in the host;
- lead to loss of blood;
- lead to loss of weight;
- lead to septicaemia;
- cause diseases/injuries/harm;
- lead to death;
- de-value the worth of animal skin/hides/ reduce the value of farm animals.
c. (i) Saprophytes
are organisms that feed; on dead/decaying/decomposing organic matter.
(ii) Examples of saprophytes
- Fungi/Bacteria/
- Mushroom
- Azotobacter
- Rhizopus;
- Clostridium
- Mucor
- Streptomycetes
- Toadstool
- Mold/mould
- Penicillium
- Saccharomyces
- Aspergillus
- Yeast.