Biology Paper 2, WASSCE (SC), 2023

QUESTION 5

  1. (i) What are sense organs?                                                                             [3 marks]

(ii) Name three sense organs that respond to the stimulus of chemicals.      [3 marks]

  1. List three animals each that exhibit the following courtship behaviours.
  2. territoriality
  3. pairing                                                                                                   [6 marks]
  4. (i) State one similarity between the eggs of toads and the eggs of birds.        [1 mark]

(ii) State three differences between the eggs of toads and the eggs of birds.  [3 marks]

  1. Complete the table below by listing four organisms involved in the nitrogen cycle and state one role each of the organisms.                                                                       

Four organisms involved in the nitrogen cycle

One role of each organism

 

 

 

 

 

 

 

 

                                                                                                                          [8 marks]

  1. Complete the table below by naming two types of heterotrophic modes of nutrition in animals and give two examples each of the organisms that carry out the modes of nutrition.

Two modes of heterotrophic nutrition

Two examples of organisms that carry out mode of nutrition

 

 

 

 

 

 

                                                                                                                                     [6 marks]

This question was attempted by many candidates.

Most candidates were able to define sense organs with examples.

Poor spellings made some candidates to lose marks for example spelling tongue as tounge, yoke instead of yolk etc.

In question 5(b)(i), many candidates could not give correct examples of animals that exhibit territoriality some instead were mentioning animals like Zebra, Elephant, Antelope etc.

Many candidates gave wrong responses in question 5(c)(iii). They wrote it is hydrated/it is not hydrated; absence of amniotic fluid/presence of amniotic fluid; cannot survive on land/can survive on land etc.

The organisms involved in nitrogen fixation and their roles were wrongly answered by many candidates.

Many candidates gave correct answers in question 5(e) Few however could not give correct examples for the mode of nutrition mentioned.

 

 

The expected answers are as follows

 

(a)      (i)    Sense organs
Organs with sensory receptors; that detect changes from the environment; and relay
the impulses to the nervous system; for interpretation and appropriate response sent
to the effector organ.                                                                          
(ii)   Sense organs that respond to the stimulus of chemicals

  • Tongue;
  • Nose;
  • Skin;
  • Eye.                                                                                             

          (b)   (i)    Animals that exhibit territoriality

  • Agama lizard/lizard;
  • Leopard/tiger;
  • Jaguar;
  • Lion;
  • Monkey;
  • Chimpanzee/baboon;
  • Dog;
  • Cat;
  • Male Tilapia.                                                                               

                 (ii)   Animals that exhibit pairing

  • Termite;
  • Human;
  • Gibbon;
  • Domestic fowl/duck/pigeon;
  • Fish;
  • Spider;
  • Monkey;
  • Toad.                                                                                           

                       
(c)   (i)    Similarities between eggs of toads and eggs of birds
Both have yolk; embryo; vitelline membrane.                                  

 

                            
(ii)   Differences between eggs of toads and eggs of birds


Eggs of toads

Eggs of birds

Surrounded by jelly coat

surrounded by calcareous shell;

Relatively smaller

relatively larger;

Shell membrane absent

shell membrane present;

Presence of black part

no black part;

Eggs are laid in chains

eggs are laid in single piece;

Many/numerous eggs

one egg at a time;

Transparent

opaque;

Airspace absent

airspace present;

Yolk not suspended by chalaza

Yolk suspended by chalaza.

                

(d)  Organisms involved in Nitrogen Cycle

Organisms involved in the nitrogen cycle

One role of organism

Animals

Excrete nitrogenous compounds/
Eat proteins in plant/
Die/decay to form ammonium compound;

Plants

Absorbs nitrate from soil/
Die/decay to form ammonium compound;

Putrefying bacteria

Break down dead plants/animals;

Azotobacter

Converts atmospheric nitrogen to nitrate;

Rhizobium

Converts atmospheric nitrogen to nitrates;

Nitrobacter

Converts nitrite to nitrates;

Nitrosomonas

Converts ammonium compound to nitrite;

Pseudomonas

Converts amino compound to ammonium compounds.

                

(e)   Types of heterotrophic nutrition


Two modes of heterotrophic
Nutrition

Two examples of organisms that carry out mode of
Nutrition

Holozoic

Human; domestic fowl; dog; cat; goat; sheep; cow;
snake; lion; rabbit; Amoeba;
Any 2x1 [2 marks]

Parasitic

Lice; tick; tapeworm; liver fluke; Guinea worm; hookworm;
Any 2x1[2 marks]

Saprophytic

Fungi; mushroom; soil bacteria; yeast;
Rhizopus; Mucor.
Any 2x1 [2 marks]