10 Biodiversity AQA Biology Exam-style mark scheme

AQA Biology

10 Biodiversity Exam-style mark scheme

Question number

Answer

1 a

animalia/animals;

fungi;

plantae/plants;

1 b i

Class Mammalia AND Family Equidae

1 b ii

2 a i 2 a ii 2 b i

2 b ii 2 b iii 2 b iv

3 a

3 bi 3b ii

Mule has 63 chromosomes/ mule has odd number of chromosomes/ horse and donkey have different number of chromosomes/ gametes have different number of chromosomes;

(leads to) errors occur in meiosis/ gamete formation/ correct description;

mule is not fertile/ is sterile/ cannot reproduce;

To show whether immune response occurred/ because cats are (genetically) related to cheetahs;

To show that rejection did not normally occur/ skin could (successfully) be grafted;

Rapid rejection between unrelated (domestic) cats / cats are not genetically similar;

Rapid rejection between (domestic) cat and cheetah/ cats and cheetahs are not genetically similar;

Slow/ no rejection in cheetahs/ cheetahs are genetically similar;

Small sample size;

Time observed was short;

Similar (antigens on all cheetahs);

Protein/antigen production is coded for by alleles/ DNA base sequence/ genes;

The more similar the protein the more similar the alleles/ genes/ DNA sequence;

The more similar the gene/ alleles/ DNA sequences the more closely related;

Grid the area of grass land/ use tapes at right angles to form axes;

Use a random number table/ random number generator on calculator to generate co-ordinates;

place quadrat at co-ordinates (and search within quadrat);

47%;

56%;

The total number of snails is different in each situation;

Marks 3 1 3

1 1 3

1 max 1 3

3

2 2

Guidance Allow if answers are written in table. Ignore reference to mule being viable. Ignore reference to control

Accept same/ not very different

? Oxford University Press 2015 oxfordsecondary.co.uk/acknowledgements

This resource sheet may have been changed from the original

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AQA Biology

10 Biodiversity Exam-style mark scheme

Question number

Answer

allows them to see if more banded snails are being eaten by birds than proportion in live population;

3 c i

predation by birds;

3 c ii

More banded snail are being eaten than might be expected if there was no preference;

less banded snails left to reproduce so numbers may fall in future populations;

4 a i

2;

4a ii

30;

4 b

song characteristic of species/ differs between

species;

song linked to courtship at night/ living underground;

4 c

females not attracted to call of male/ does not

recognise male;

because of difference in song;

song necessary precursor to mating;

hybrids are sterile;

5 a

Fewest people at site R as mean is lowest;

Standard deviations do not overlap so significant/not due to chance;

5 b i 5 b ii

5 c 5 d i

(Would not be reliable as) number of species is still increasing;

Idea of curve has flattened/no more species found so no benefit/no point/takes unnecessary time/takes unnecessary effort / can get same results with fewer quadrats;

Combustion/ would burn/cause loss of substances (other than water)/named substance/cause loss of dry mass;

The site/site U with most people/34.6 has the largest ratio/3.24; (Large value of ratio due to) large biomass ? small number / large size ? small number/biomass greater than abundance;

Marks 1 2 1 1 2

2 max

2

1 1

1 2

Guidance

Allow 1.75. Check that final version printed gives this answer. Allow 60 divided by answer for a i

Accept use of mean values to show 2.2 is the lowest Accept use of values/description of standard deviation even if wording `standard deviation' is not used. Accept: has not reached peak/maximum or if shown by values Basic idea is of minimising effort. If values used reward idea rather than accuracy of numbers Accept: only want water to be lost Ignore: reference to decomposition Accept: as number of people increases, ratio increases Explanation of seaweed ratio

? Oxford University Press 2015 oxfordsecondary.co.uk/acknowledgements

This resource sheet may have been changed from the original

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AQA Biology

10 Biodiversity Exam-style mark scheme

Question number

Answer

5 d ii

1. Fewer larger animals/more smaller animals where more people/more disturbance;

2. 0.09 linked to 34.6/appropriate link between row 4 and row 1;

3. Larger animals affected by human activity;

4. Smaller animals are young animals;

5. Fewer species of seaweed (with disturbance);

6. (So) fewer niches /habitats (for large animals);

Marks 4 max

Guidance

Principle Use of data Accept: converse Accept: converse Accept if shown by figures Accept idea of disturbance/ damage to niche/ habitat

? Oxford University Press 2015 oxfordsecondary.co.uk/acknowledgements

This resource sheet may have been changed from the original

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