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]
Explanation
a. Table
|
Organism |
Mode of feeding |
Feature of mouthpart that adapts organism to mode of feeding |
|
Adult mosquito |
Fluid feeding/piercing/sucking |
Proboscis/modified long mandible and maxillae |
|
Weevil |
Chewing/boring |
Possession of pointed short and strong rostrum |
|
Cockroach |
Biting/chewing |
Well developed mandibles/strong sharp mandibles |
b. Parts of alimentary canal of earthworm
– Mouth;
– Pharynx;
– Oesophagus/gullet;
– Crop;
– Gizzard
– Intestine;
– Anus.
c. Ways by which water could be polluted by agricultural practices
– Farmers add excess fertilizers/organic material to soil which may cause water pollution;
– The inorganic/artificial fertilizers that contain high concentrations of nitrates and phosphates, dissolves in rain water and washed into nearby streams and rivers;
– Nitrates and phosphates accelerate the growth of algae/eutrophication;
– The death/decay of algae in rivers and streams increase the population of bacteria rapidly;
– And cause oxygen level to decrease drastically;
– Killing aquatic organisms;
– Use of chemicals/dynamite for fishing which pollutes water
– Dumping of cleared vegetation on water bodies;
– Slash-burn methods of farming which might wash ash to nearby rivers/water bodies;
– Pesticides/insecticides also sprayed on crops are usually non-biodegradable;
– They are washed into nearby rivers/streams/water bodies;
– Accumulate in the bodies of aquatic organisms;
– And are passed along the food chain;
– The concentration of pesticides/insecticides can reach toxic level in the bodies of the final consumers in the higher trophic levels is causing these organisms to die;
d. (i) Life cycle of a Housefly
– The female housefly lays eggs on decomposing matter/rubbish;
– The eggs hatch into larvae/maggot;
– In a few hours;
– They crawl unto food;
– Which if solid will be digested by enzymes to liquid;
– The larvae have twelve segments on the body;
– The body then contracts;
– The skin hardens and turns brown to enclose the pupa;
– After about four days, the pupa changes into the adult/imago;
– Inside the puparium/brown skin cover;
– The adult fly then emerges;
– And flies away.
OR
e. Diagram of a mature maize seedling