Download AQA Biology Question number Answer Marks Guidance 1 a

10 Biodiversity
Exam-style mark scheme
AQA Biology
Question
number
1a
Answer
animalia/animals;
Marks
Guidance
3
fungi;
plantae/plants;
1bi
Class  Mammalia AND Family  Equidae
1
1 b 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;
3
Allow if answers are written in
table.
Ignore reference to mule being
viable.
(leads to) errors occur in meiosis/ gamete formation/
correct description;
mule is not fertile/ is sterile/ cannot reproduce;
2ai
To show whether immune response occurred/
because cats are (genetically) related to cheetahs;
1
2 a ii
To show that rejection did not normally occur/ skin
could (successfully) be grafted;
1
2bi
Rapid rejection between unrelated (domestic) cats /
cats are not genetically similar;
3
Ignore reference to control
Rapid rejection between (domestic) cat and cheetah/
cats and cheetahs are not genetically similar;
Slow/ no rejection in cheetahs/ cheetahs are
genetically similar;
2 b ii
Small sample size;
1 max
Time observed was short;
2 b iii
Similar (antigens on all cheetahs);
1
2 b iv
Protein/antigen production is coded for by alleles/
DNA base sequence/ genes;
3
Accept same/ not very different
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;
3a
Grid the area of grass land/ use tapes at right angles
to form axes;
3
Use a random number table/ random number
generator on calculator to generate co-ordinates;
place quadrat at co-ordinates (and search within
quadrat);
3 bi
47%;
2
56%;
3b ii
The total number of snails is different in each
situation;
© Oxford University Press 2015
2
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10 Biodiversity
Exam-style mark scheme
AQA Biology
Question
number
Answer
Marks
Guidance
allows them to see if more banded snails are being
eaten by birds than proportion in live population;
3ci
predation by birds;
1
3 c ii
More banded snail are being eaten than might be
expected if there was no preference;
2
less banded snails left to reproduce so numbers
may fall in future populations;
4ai
2;
1
Allow 1.75. Check that final
version printed gives this
answer.
4a ii
30;
1
Allow 60 divided by answer for
ai
4b
song characteristic of species/ differs between
species;
2
song linked to courtship at night/ living underground;
4c
females not attracted to call of male/ does not
recognise male;
2 max
because of difference in song;
song necessary precursor to mating;
hybrids are sterile;
5a
Fewest people at site R as mean is lowest;
2
Standard deviations do not overlap so significant/not
due to chance;
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.
5bi
(Would not be reliable as) number of species is still
increasing;
1
Accept: has not reached
peak/maximum or if shown by
values
5 b ii
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;
1
Basic idea is of minimising
effort.
Combustion/ would burn/cause loss of substances
(other than water)/named substance/cause loss of
dry mass;
1
The site/site U with most people/34.6 has the largest
ratio/3.24;
2
5c
5di
If values used reward idea
rather than accuracy of
numbers
Ignore: reference to
decomposition
(Large value of ratio due to) large biomass ÷ small
number / large size ÷ small number/biomass greater
than abundance;
© Oxford University Press 2015
Accept: only want water to be
lost
Accept: as number of people
increases, ratio increases
Explanation of seaweed ratio
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This resource sheet may have been changed from the original
2
10 Biodiversity
Exam-style mark scheme
AQA Biology
Question
number
5 d ii
Answer
Marks
1. Fewer larger animals/more smaller animals where
more people/more disturbance;
4 max
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);
Guidance
Principle
Use of data
Accept: converse
Accept: converse
Accept if shown by figures
Accept idea of disturbance/
damage to niche/ habitat
6. (So) fewer niches /habitats (for large animals);
© Oxford University Press 2015
www.oxfordsecondary.co.uk/acknowledgements
This resource sheet may have been changed from the original
3