Download 9Ce-1geneandevo

9Ce-1
Genetics and evolution
Name
Class
Date
These statements describe what you should have learnt about.
B33
B34
B35
B36
B37
B38
B39
genetic information is passed from one generation to the next; this is called heredity
how heredity occurs, including knowledge of chromosomes, genes and DNA,
and the part played by Watson, Crick, Wilkins and Franklin in the development
of the DNA model
there are differences between species
the variation between individuals within a species can be continuous
or discontinuous
the variation between species and between individuals of the same species
means some organisms compete more successfully, which can result in natural
selection
changes in the environment may leave individuals within a species, or an entire
species, less well adapted to compete successfully and reproduce, which may
cause extinction
why it is important to maintain biodiversity and the use of gene banks to help
do this
9A
9A
7D
7D, 9A
9A
7D, 9A
8B, 9A
Circle the correct answers to these two multiple choice questions.
1 Chromosomes are found in:
[1 mark]
A the nuclei of all cells
B the nuclei of gametes only
C animal cells only
D chloroplasts.
2 A gene bank may store:
[1 mark]
A money made from genes
B gametes
C money to be used for biodiversity projects
D red blood cells.
Revise what you have learnt about the statements above. Use the Student Book, Summary Sheets
and your own notes. Then answer the questions below on a separate sheet of paper.
3 What does genetic information do for an organism?
[1 mark]
4 Describe how DNA, genes and chromosomes are linked to each other.
[2 marks]
5 Give the names of the two scientists who finally solved the structure of DNA.
[2 marks]
6 State what is meant by the term species.
[2 marks]
7 Some people can roll their tongues and others cannot. Explain whether this is an example of
continuous variation, discontinuous variation or is not an example of either type.
[2 marks]
8 The level of water in a lake gradually gets higher and higher over thousands and thousands of
years. As this happens the legs of wading birds, which eat creatures from the mud on the
bottom of the lake, get longer. Use the idea of natural selection to explain how scientists think
that the bird’s legs got longer.
[4 marks]
9 The dodo bird became extinct after animals such as rats and pigs were introduced to the island
on which it lived. Suggest two ways in which this change in the environment might have caused
the extinction of the birds.
[2 marks]
10 State one reason why we should preserve biodiversity.
[1 mark]
Mark your own answers and identify areas that still need more work by highlighting the statements
in the table at the top as red, amber or green.
What activities are you going to do to improve your understanding in any weak areas?
© Pearson Education Ltd 2015. Copying permitted for
purchasing institution only. This material is not copyright free.
11
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9Ce-1
Genetics and evolution
Answers
Q
NC
Answer
Mark Scheme
1
B34
A the nuclei of all cells Any cell that has a nucleus will contain
chromosomes.
1 mark
2
B39
B gametes A gene bank is a store of material that can be used to
produce organisms.
1 mark
3
B33
controls what an organism does/looks like
1 mark
4
B34
chromosomes contain genes
genes (and chromosomes) are made of DNA
2 marks (1 for each
point)
5
B34
James Watson and Francis Crick
You don’t need their first names. Note that Wilkins and Franklin
helped solve the structure of DNA but the question asks for the
two scientists who did the final working out.
2 marks (1 for each
name)
6
B35
a set of organisms that can breed together
their offspring can also reproduce
Make sure that you have used the word organisms and
not animals.
2 marks (1 for each
point)
7
B36
discontinuous
because discontinuous variation is variation that only has a
limited number of choice
2 marks (1 for each
point)
8
B37
as the water level rose, some birds by chance had longer legs
the longer legged birds could wade further into the lake and so
find more to eat
so the longer legged birds would be more likely to survive
and reproduce
so the next generation of birds would have more birds with
longer legs
4 marks (1 for each
point)
9
B38
Two of:
● the new animals ate the birds eggs
● the new animals ate the birds (probably just the young chicks)
● the new animals destroyed the areas where the dodos liked
to live or nest
● the new animals ate all the food that the dodos would
normally eat.
There were probably three real reasons for the extinction of the
dodos: they were easy to hunt for the sailors who landed on the
island; their eggs and young were eaten by rats and other
animals brought to the island by humans; their habitat was
destroyed by humans as they cut down forests to get wood for
boats and buildings.
2 marks (1 for each
point)
10
B39
One of:
● Organisms are interdependent and so if one dies
out/becomes extinct it affects all the organisms in an area.
● There are many undiscovered substances in organisms that
may be useful to us and so we should stop organisms
becoming extinct.
● Areas with greater biodiversity recover better from natural
disasters (such as fires or floods).
1 mark
© Pearson Education Ltd 2015. Copying permitted for
purchasing institution only. This material is not copyright free.
12
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