Biology Paper 2, WASSCE (PC 2ND), 2022

Question 3
An ecosystem comprising a pond, monkeys, palm trees, rats and mushrooms had just been flooded. Use the information to answer questions 3(a) to 3(d).
(a)        (i)         What is an ecosystem?
[2 marks]
(ii)        State three characteristics of an ecosystem.
[3 marks]
(b)        State four effects that the flood would have on the ecosystem.
[4 marks]
(c)        On the table below, list four abiotic factors in the ecosystem and name one instrument each used for measuring the factor.


Abiotic factor

One measuring instrument

 

 

 

 

 

 

 

 

                                                                                                                        [8 marks]
(d)       Name three habitats in the ecosystem.                                               [3 marks]

Observation

 

Many candidates that answered this question could not give the expected answers to the question. Candidates performed well in this question. Spelling errors affected most candidates in their responses to the question.

Some candidates were able to explain ecosystem and state the characteristics of an ecosystem.
Many candidates were not able to state the effect of flood on the ecosystem satisfactorily.
Some candidates could not spell abiotic factors and the instruments for measuring them.

The expected answers are:

(a)  (i)         Ecosystem
Is a biological community; that comprises biotic/living/plant/animal components; and abiotic/non-living/physical components.                                                  

(ii)        Characteristics of an ecosystem

        • it is made up of biotic/living/ components/plant/animal;
        • and abiotic components/non-living/physical and chemical factors;
        • the biotic and abiotic components interact together;
        • there is a flow of energy from the sun;
        • there is a recycling of nutrients.                                      

            (b)        Effect of flooding on the ecosystem

        • there would be soil erosion;
        • increase in humidity;
        • some terrestrial habitats will be destroyed;
        • increase in volume of water in rivers/water bodies;
        • availability of water/more water in the ecosystem;
        • some terrestrial animals/plants will be destroyed/die;
        • establishment of new habitats;
        • increased turbidity;
        • lowered temperature;
        • facilitate growth of vegetation/flora;
        • outbreak of diseases/water-borne diseases.                                             

            (c)        Abiotic factors and instruments


Abiotic factors

Instrument

Rainfall

Rain gauge

Humidity

Hygrometer

Atmospheric pressure

Barometer

Temperature

Thermometer

Wind direction

Wind vane

Wind speed

Anemometer

Turbidity

Secchi disc

Oxygen

Oxygen meter

Light intensity

Photometer/light meter

pH

pH meter/paper

Topography

Slope gauge

Height/altitude

Height meter/Altimeter

                       
Note: Spelling of any four (4) abiotic factors and any four (4) instruments must be correct to score the 8 marks.

            (d)       Habitats in the ecosystem

  • aquatic;
  • terrestrial;
  • arboreal.                                                                                              

Note: Spelling must be correct to score.