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Year 10, Pathway C
2012
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From a previous lesson...
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Variation is the differences between the
characteristics found within a species
(controlled by genes)
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Inheritance is the passing of the parents’
characteristics (genes) to their offspring
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Genes – location on a chromosome that
controls a specific characteristic (eg: eye
colour)
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Allele – The different characteristics that a
gene can produce (eg: blue eyes or brown
eyes)
Allele for red flowers
Matching pair of
chromosomes of a
flowering plant
Allele for white flowers
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Inheritance
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Intermediate
Dominant/recessive
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Intermediate inheritance: Offspring will show
characteristics that combine the alleles of the
parents
BB
Cow
WW
Bull
BW
Calf
We call the calf the F1 generation. If the calf grows up and
produces further offspring they would be F2.
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Genotype – Description of the alleles of the
organism for a particular characteristic (eg:
BB, WW or BW for fur colour)
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Phenotype – the visible characteristic (eg:
black, white or grey fur colour)
What is the genotype of the
Easter bunny’s coat?
What is the phenotype of the
Easter bunny’s coat?
What would the offspring of a grey bull mating
with a black cow be like?
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Parent phenotype:
Grey
Parent genotype:
BW
Parent gametes:
B
W
Offspring:
BB
BB
How many offspring have black fur?
How many offspring have white fur?
How many offspring have grey fur?
Black
BB
B
B
BW BW
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Homozygous – another word for pure bred. It
means the organism has matching alleles (eg:
BB or WW, NOT BW)
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Heterozygous – cross bred. Organism will
have mismatched alleles (eg: BW)