iGCSE Biology (0610) 1.3 Features of organisms iGCSE Style Questions Paper 3

Question

(a)    Fig. 4.1 shows the structure of a typical fish.

Fig 4.1

Fig. 4.2 shows four species of freshwater fish, A, B, C and D.

Biologists use dichotomous keys to identify different species.

Describe one visible feature of each species of fish A, B, C and D, that could be used to distinguish it from the other three species in Fig. 4.2.

Only use descriptions of the features labelled in Fig. 4.1 in your answers.

Write your answers in Table 4.1.

Table 4.1

(b)     Pollution is harm done to the environment by release of substances produced by human activities. Acid rain is one form of pollution that damages many lakes, ponds and rivers.

(i)    State one pollutant that causes acid rain.

(ii)   Fig. 4.3 shows the effect of pH on the mean number of species of fish found in lakes in New York State, USA.

         Describe the results shown in Fig. 4.3.

(iii)   Explain the effects of acid rain on the environment.

Answer/Explanation

Ans:   

(a)     A

extended/elongated, lower mandible ;

lower mandible longer than upper mandible ora/ AW ;

rounded caudal fin ;

B

thin/narrow/ elongated, fin(s) ;

combined dorsal and caudal fin ;

C

spotted fin(s) ;

more than one dorsal fin ;

D

elongated/long(er), upper mandible ;

forked caudal fin/AW ;

extra fin, on side/ bottom ;

(b)     (i)      sulfur dioxide ;

nitrogen oxide(s) ;

(ii)     1   increase in pH to 7.0 increases the number of species of fish ;

2   most species of fish were present at pH 7.0 and 7.5 ;

3   least species of fish were present at pH 4.0 ;

4   increase in pH above 7.5 decreases the number of species of fish ;

5   small changes in number of species of fish between pH 6.5 – pH 8.0 ;

6   large change in the number of species of fish between pH 4.0 – pH6.5 ;

7   acidic lakes have fewer fish species than pH neutral/ alkaline lakes ora;

8   reference to mean number of fish species at a particular pH ;

(iii)    reduces the pH of rivers / lakes / soils ;

(low pH) kills / harms, fish/ invertebrates ;

(low pH) causes aluminium compounds to become soluble ;

aluminium compounds toxic to aquatic life ;

kills / harms, trees / lichens /plants ;

mineral/ s / ions / salts, washed out of soil ;

damages limestone, buildings / statues /rock ;

Question

Arachnids, crustaceans, insects and myriapods are all classified as arthropods.
     Scorpions, such as Heterometrus swammerdami shown in Fig. 1.1, are arachnids.

               

     (a) State three features, shown by H. swammerdami and visible in Fig. 1.1, that arachnids
             share with other arthropods.

           

     (b) Fig. 1.2 shows seven species of arachnid.

                       

         Use the key to identify each species. Write the letter of each species (A to G) in the correct
         box beside the key. One has been done for you.

       

Answer/Explanation

Ans:

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