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DO NOWDate:10/13
Put homework away.
In your own words:
Describe why two brown-haired parents can have a blonde-haired child.
Use complete sentences.
ESSENTIAL QUESTION:How are traits passed from parents to offspring (children)?
OBJECTIVES:-Trait Bracelets-Vocabulary T-Charts
Chromosome Bracelets1) Create a Chromosome
with two pipe cleaners2) Select beads that
represent your traits and put them on your bracelet
HAIR COLOR: Black/Brown:1 Blue, 1 Green Blonde: 2 green
HAIR TEXTURE: Curly Hair:1 Red,1 Orange Straight : 2 Orange
Vocabulary T-Charts pg 47
• USE YOUR• TEXTBOOKS• PGS 218-219• OR GLOSSARY• TO FILL IN THE • INFORMATION
EXIT TICKET page 48
Refer to your bracelet, and answer the following questions:
• Is your genotype for hair color heterozygous or homozygous?
• Which allele is dominant and which is recessive?
• How do you know?
DO NOWDate:10/14 &10/15
Describe homozygous and heterozygous alleles in your own words.
Use textbooks or notes.
ESSENTIAL QUESTION:How are traits passed from parents to offspring (children)?
OBJECTIVES:-Finish Vocabulary T-charts-Genotype/Phenotype Activity-Dragon Fly Genetics
Observing Traits pg
Glue this chart on page 51 in your notebooksTrait Your phenotype Your Genotype
Hair Color
Tongue Rolling
Eye color
Hair texture
Hairline
Type of earlobe
Shape of little fingerShape of nose
Observing Traits
Use the pictures on the sheets at your table to fill in your phenotypes and genotypes.
One Sentence Summary pg 33
Read each paragraph and record a one sentence summary under your trait chart.
1) Genes are ___________________________
2) Dominant genes ______________________
3) Recessive genes _______________________.
Traits Practice pg
Copy these parent alleles on the top of page 50 of your notebook
no
Traits Practice
• Answer the following questions on page 50 of your notebook in complete sentences.
1.Which parent gave the brown hair allele for hair color?
2. What is the phenotype of the offspring’s hair color?
3. What is the phenotype of the offspring’s hairline on their forehead?
4. Will the offspring be able to roll his/her tongue? How do you know?
Dragonfly Genetics
Male
Alleles
Female
Alleles
What is the code?
(ee)
What does it look like?
(white eyes)
What does the baby dragonfly
look like?
DO NOWDate:10/17
Q: How are traits passed from parents to offspring (children)?
How are the genotype and phenotype of an organism related?
ESSENTIAL QUESTION:How are traits passed from parents to offspring (children)?
OBJECTIVES:-Brainpop-Heredity-Punnett Square Activity-Exit Ticket
Punnett Squares
Punnett Square – a chart used to show four possible ways that genes can be combined when passed from parents to offspring as a result of reproduction.
Father’s genotype – on side of squareMother’s genotype – on top of square
Offspring Possibility
#1
Offspring Possibility
#2
Offspring Possibility
#3
Offspring Possibility
#4
Mother’s Genotype
Allele 1
Fat
her
’s G
eno
typ
e
Allele 2
Allele 2Allele 1
Female Male
Important to know before getting started:
Punnett’s Square
Scientists use a Punnett’s square to determine the possible genetic outcomes for the offspring that result from the combination
of the parent’s genes.
Black colored fur is the dominant trait.
We will use the Punnett’s Square to determine the offspring of guinea pigs. The
offspring will either be black or white.
BBbb
Generation 1
B B
b
b
In this case we have a dad with black fur and a mother with white fur. Because black is the dominant gene, we
write it with a capital ‘B’.
Generation 1
B B
b
b
White fur is a recessive trait. It is written with a lowercase ‘b’. It does not matter what letter we choose
to represent a gene, but capital letter is always dominant and lowercase is always recessive.
Generation 1
B B
b
b
To complete the Punnett’s square we combine the gene from mom with the gene from dad. We always write
the dominant gene first.
Bb
Generation 1
B B
b
b
We write the dominant gene first because it “masks” the recessive gene. Therefore, the color of the guinea
pig with the genes Bb would be black.
Bb
Generation 1
B B
b
b
Copy this Punnett’s square into your notebook. Try and fill out the remaining offspring on your own. When you
are done, go to the next slide.
Bb
Generation 1
B B
b
b
Bb Bb
Bb Bb
We say an individual is heterozygous when it has two different genes.
What percentage of these offspring are heterozygous?
Generation 1
B B
b
b
Bb Bb
Bb Bb
100% are heterozygous black.
We will now take one female and one male from this generation to cross for our second generation.
If these two were to mate, what would be the traits of their offspring?
Here are two of the offspring in our first generation.
BbBb
Generation 2
B b
B
b
What will the gene combinations be for these offspring?
Copy this into your notebook and try to fill out the Punnett’s square. Continue when you are done.
Generation 2
B b
B
b
We have completed is the genotype for all the offspring. Genotype refers to the gene combination that an individual has. Can you figure out what the
phenotype of these offspring will be?
BB
Bb
Bb
bb
Generation 2
B b
B
b
What you have just determined is called the phenotype. The phenotype is what we see as a result
of an individual's genes.
BB
Bb
Bb
bb
black black
black white
Generation 2
B b
B
b
BB
Bb
Bb
bb
We say an individual is homozygous when it has two of the same genes.
Can you find a homozygous black guinea pig?
Generation 2
B b
B
b
BB
Bb
Bb
bb
The entire Punnett’s square represents all possible outcomes. That means each small box represents 25%
of the offspring.
What percentage of the offspring are homozygous black?
This individual is homozygous black.
Generation 2
B b
B
b
BB
Bb
Bb
bb
25% of the offspring are homozygous black. Try the next two on your own:
____% are homozygous white
____% are heterozygous black
Generation 2
B b
B
b
BB
Bb
Bb
bb
25% are homozygous black.
25% are homozygous white
50% are heterozygous black
Notice: This will always add
up to 100%.
The unattached earlobe is the dominant trait.
The attached earlobe is the recessive trait.
Now we will examine some human traits.
Earlobes can be either unattached (A) or attached (a)
Unattached
Attached
a
A
Earlobes
e e
E
e
Copy this Punnett’s square into your notebook. Determine both the genotype and phenotype.
What percent of offspring will have attached earlobes?
Earlobes
e e
E
e
50% percent of offspring will have attached earlobes.
Ee Ee
ee ee
Tongue curling is the dominant trait.
Non-curling is the recessive trait.
The ability to curl your tongue is also genetic.
Tongue Curling
T t
T
T
Copy into your notebook and complete the Punnett’s Square.
What percentage of offspring will be able to curl their tongue?
Tongue Curling
T t
T
T
100% percent of offspring will be able to curl their tongues.
TT Tt
TT Tt
Punnett Square – example
• Top left box = Mother’s first allele, Father’s first allele
• Top right box = Mother’s second allele, Father’s first allele
• Bottom left box = Mother’s first allele, Father’s second allele
• Bottom right box = Mother’s second allele, Father’s second allele
Use this chart of cat
traits to complete your page
182-184 Punnett Square activity.
Exit Ticket
• Create a concept map using the following words:
Cell phenotype Nucleus genotypeChromosomes alleleGenesPassing of traitsSections of DNA
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