Biology Paper 3 (Practical), May/June 2015

Question 2

     

    Study specimens G and H carefully and use them to answer
                            questions 2(a) to 2(c).

                            (a) (i)   Name the phylum of specimens G and H.                                            

    [1 mark]       

    (ii)   State two reasons for the answer given in 2(a)(i)                                 [2 marks]

                            (b)        Name the structures on specimens G and H that are used for defense [2 marks]

                            (c) 

    (i) State the habitat of each of specimens G and H.                                   [2 marks]
    (ii) State two ways in which each of specimens G and H are of economic importance.
    [4 marks]

    Study specimens M, N and P carefully and use them to answer questions 2(d) to 2(e).

    (d) (i)   Name the Class of organisms to which each of specimens M, N and P are associated.                                                                                               [3 marks]   
    (ii)  State one function common to the specimens named in 2 (d) (i).         [1 mark]

    (iii) In a tabular form, state four observable differences between specimens M and P.                                                                                                                                                     [4 marks]
    (e) Explain three features of biological importance in specimen M.                 [6 marks]

        

Observation

Many candidates could answer this question properly but some could not spell the Phylum of specimens G and H properly while some candidates started the spelling of the phylum in small letter. Also the reason given for the answer in (a) (i) was incorrect.

Many candidates could state the structures on specimens G and H used for defense. Many could also state the habitat of specimens G and H and the economic importance.

Many candidates could not answer question (d) (i) and (ii) correctly. Candidates could answer question (d) (iii) well but (e) was not answered properly because they did not state the structures and functions.

       

 

                                                                                                                                                             
The expected answers include:           

  • (a) (i) Phylum of specimens G and H

Arthropoda                                                                                                                
NOTE: If two answers are given and one is wrong, mark both wrong.
(ii) Reasons

  • Presence of jointed legs/appendages;
  • Presence of chitinous exoskeleton;
  • Metamerically segmented;
  • Bilateral symmetry;
  • Have three body layers/triploblastic.  
  •  
    (b) Structures of specimens G and H used for defence
    G         -           Sting/Ovipositor;
    H         -           (Strong and powerful/biting) mandible/jaw.  

    (c) (i) Habitats of specimens G and H
    G         -           (Bee) Hive
    H         -           Termitarium/anthill/termite mound/nest/soil/old logs of trees/timber of wooden buildings.                                                                        
    (ii) Economic importance of Specimens G and H

    G        

    -           It pollinates flower;
    -           produces honey;
    -           produces wax;
    -           sting causes pain/death
    -           bee keeping is a source of employment/income.

    H        

    -           it destroys wood/furniture/books;
    -           it destroys crops/plants;
    -           the termitarium is used for lawn tennis court;
    -           source of food/protein.
    -           aids soil aeration through tunneling;
    -           enhances penetration of water into the soil/increases porosity;
    -           introduces vegetable/plant matter into the soil/increases humus contents;
    -           their mound/termitarium forms impediments to land use.                             

    (d) (i) Class of organisms to which specimens M, N and P belong

    M        -           Aves
    N         -           Osteichthyes
    P          -           Mammalia

    (ii) Common features of specimens M, N and P
    Protection of the organism (against mechanical injury/desiccation)

    (iii) Observable differences between specimens M and P


    Specimen M/Quill feather

    Specimen P/Mammalian skin with hair

    - Presence of inferior umbilicus

    absence of inferior umbilicus;

    - Presence of superior umbilicus

    absence of superior umbilicus;

    - Presence of after shaft

    absence of after shaft;

    - Presence of shaft/rachis

    absence of shaft/rachis;

    - Presence of Quill/calamus
    - Presence of barbs

    absence of Quill/calamus;
    absence of barbs;

    - Absence of hair/fur

    presence of hair/fur;

    - Texture is hard when touched

    texture is soft when touched;

    - Barbs are restricted to certain parts of the Quill

    Hairs/fur cover the whole surface of the specimen.

    Penalty: minus 1 mark for no tabulation.

    (e) Structures of biological importance in Specimen M
    - Presence of Quill feather; serves as water proof/protection/keeps the bird warm/insulation;
    - vane is flat/broad; to provide surface area for flapping during flight/against desiccation;
    - rachis/shaft which is centrally placed; to provide point of attachment to barbs/strengthen the feather;
    - barbs with hooks; interlock to form the vane;
    - the overlapping arrangements of Quill feathers over the body of birds; allows smooth movement/little resistance in flight;
    - colouration of the Quill feather; enhances courtship display/camouflage.                                                                                                                                                                                      
    NOTE: Correct structure alone can score one mark.
      Correct structure and function to score two marks.