Essential Biology 10.3 Polygenic Inheritance (AHL)
Due Date:
Student Name:
Candidate Number: 002171-
Blog resource: http://tinyurl.com/l363hk
Click4Biology: http://click4biology.info/c4b/10/gene10.htm
Cite all sources using the CSE method (or ISO 690 Numerical in Word. Highlight all objective 1 command terms in
yellow and complete these before class. Highlight all objective 2 and 3 command terms in green – these will be
part of the discussions in class. After class, go back and review them.
Complete the self-assessment rubric before submitting to Moodle. Avoid printing this if possible.
1. Define polygenic inheritance.

2. Distinguish between polygenic inheritance and multiple alleles.

3. List one human and one plant example of polygenic inheritance.

4. Define contributing allele.

5. Polygenic inheritance gives rise to continuous variation within a population.
Explain what this means, using skin colour as an example.




6. Assume that two genes (A and B) are responsible for inheritance of skin colour, with two alleles
each and that they are unlinked. The dominant alleles code for melanin production.
a. Calculate the number of possible genotypes.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 10.3 Polygenic Inheritance (AHL)
Due Date:
Student Name:
Candidate Number: 002171-
b. Apply the possible genotypes to the range of phenotypes below:
aabb
Aabb
c. Explain why the phenotypes show a normal distribution.


7. Using a punnet grid, explain why it is possible for children to have skin which is darker or lighter
than both parents.
Mother genotype:
Father genotype:
AB
i.
Ab
aB
ab
AB
Ab
aB
ab
Outcome and explanation.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 10.3 Polygenic Inheritance (AHL)
Due Date:
Student Name:
Candidate Number: 002171-
8. Compare the advantages and disadvantages of light and dark skin.
Light Skin
Dark Skin
Lack of exposure to sunlight can
result in vitamin D deficiency
Cold Climate
Hot Climate
9. State precautionary measures that could be taken by:
a. Pale-skinned people to avoid the dangers of hot climates?

b. Dark-skinned people to reduce the disadvantage of a cold climate?

10. A characteristic is controlled by two unlinked genes with two alleles. Deduce the number of
possible genotypes and phenotypes.

11. A characteristic is controlled by three genes with two alleles each. Calculate the number of
genotypes possible in a cross between a homozygous recessive father and a homozygous
dominant mother.

12. Wheat kernel colour is controlled by three unlinked genes (A, B and C). The dominant alleles
code for production of a red pigment. Deduce the phenotype ratio expected in a test cross with
a wheat plant that is homozygous dominant for A, heterozygous for B and homozygous
recessive for C. Show your working.
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
Essential Biology 10.3 Polygenic Inheritance (AHL)
Due Date:
Student Name:
Candidate Number: 002171-
Works Cited
1. Allott, Andrew. IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-019-915143-1.
2. Mindorff, D and Allott, A. Biology Course Companion. Oxford : Oxford University Press, 2007. 978099151240.
3. Clegg, CJ. Biology for the IB Diploma. London : Hodder Murray, 2007. 978-0340926529.
4. Campbell N., Reece J., Taylor M., Simon. E. Biology Concepts and Connections. San Fransisco :
Pearson Benjamin Cummings, 2006. 0-8053-7160-5.
5. Taylor, Stephen. Science Video Resources. [Online] Wordpress, 2010.
http://sciencevideos.wordpress.com.
6. Burrell, John. Click4Biology. [Online] 2010. http://click4biology.info/.
7. IBO. Biology Subject Guide. [Online] 2007. http://xmltwo.ibo.org/publications/migrated/productionapp2.ibo.org/publication/7/part/2/chapter/1.html.
Self Assessment:
Essential Biology
Criterion
Presentation &
Organisation
Academic
Honesty
Objective 1
understanding
Objective 2
understanding
Objective3
understanding
Logic, notation,
mathematical
working
Further research
Assessment
Complete (2)
Partially complete (1)
NA
Complete and neat. All command terms
highlighted, tables and diagrams well presented.
Self
Sources cited using the CSE (ISO 690 numerical)
method, with Works Cited section complete and
correct.
All answers for the following command terms
Most answers for the following command terms
correct:
correct:
Define
Draw
Label
List
Measure State
Most answers for the following command terms
All answers for the following command terms correct:
correct:
Annotate Apply
Calculate Describe Distinguish Estimate Identify
Outline
Most answers for the following command terms
All answers for the following command terms correct:
correct:
Analyse Comment Compare Construct Deduce Derive Design Determine Discuss
Evaluate
Explain Predict
Show Solve
Sketch Suggest
Answers are presented in a logical and concise
manner. SI units used most times, with correct
NA
unit symbols and definitions of terms. All
mathematical working shown.
Evidence is apparent of research and reading
beyond the textbook and presentations to find
correct answers to challenging questions. If any
NA
questions are unanswered, this criterion scores
zero.
NA
Total (max 10):
Stephen Taylor
Bandung International School
http://sciencevideos.wordpress.com
MrT