June 2001 W1

summer 01 unit3 W1

Unit 3 6103102

June 2001 Mark Scheme

Suitable tabular format ; Rows and columns headings correct with units ; Correct calculation of percentage, open / closed-; ; (1 error = 1 mark 2 errors = 0 ) ; i

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4 marks (b)

Axes - correct orientation and labels ; Scale -use of more than half paper correct scale ; Plot - all points plotted correctly Line - well drawn through all points ;

(c)

4 marks

Longer time leads to increased number of open stomata ; No stomata open before 2 minutes ; All stomata open in 10 minutes ; Most / 58.1 %, stomata, open between 4-6 minuted some manipulation of figures ;

M a x 2 marks

summer 01 unit3 W1

June 2001 Mark Scheme

Unit 3 6103102

Time needed to count stomata affects results ; Light fiom microscope could affect results ; Difficult to judge, open 1 closed or some not fully open eq- ;

No check on state of stomata in the dark ; Stomata not from same area of leaf;

Max 2 marks

Light causes stomata to open ; Effect not immediate 1 delay in opening I ref to mechanism of opening takes time ; Not all stomata open at the same time ;

Max 2 marks Total 14 marks

summer 01 unit3 W1

/

June 2001 Mark Scheme

Unit 3 6103102

I 1.Comparison made, at same time of year /just before mowing I at same time of day ;

2.Standardise sample areadcheck abiotic factors;

3.Suitable method namedbe of quadrats; 4.Randomly select areas/description of placing of quadrats; 5.Quadrat number (minimum 5)lrepeat sampling;

6.Name of technique used for animal collection e.g. pooter/sweep net/animal trapdmark recapture; 7.Description of technique e.g. standard number of sweepshked search ; &Standard removal of all vegetation;

9. Identify animals as herbivores (in the field or Iaboratory) using, keys / structural features ; 10.Weigh herbivores and weigh vegetation ; 11.Return animals to habitatleq ; Max 9 marks

Suitable table with labelled rows and columns ; Averagelmean, mass of, herbivores / vegetation (accept h m table) ; Present data as pyramiWsuitab1e graphical intrpretation; Presentation clearly comparable;

Max 3 marks

June 2001 Mark Scheme

(c)

Unit 3 6103102

1. Ref to seasonal variations/dificulty in controlling abiotic factors; 2.Reference to small size of sample area / limited number of quadrats used ; 3.Not all herbivores collected / some fly away / some escape / difficult to identify (as herbivores) ;

4.Not all vegetation collected / underground parts remain in soil ; 5 .Carnivores may consume herbivores (before

weighing) ; 6.Investigate, in different mowing regimes/effects of no mowing; 7.Investigate, all trophic levels/carnivores; 8.Investigate at different times of yearlextended time; 9.Investigat.e at different phases of the mowing cycle ; 10.Investigat.epyramids of energyldry mass;

M a x 6 marks Total 18 marks

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