Mrs. Anna Ward Seventh Grade Science Ridge Road MS

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 Quiz tomorrow to Check for Understanding  Progress Reports tomorrow at the end of class  Writing Tasks  Missing Assignments—Last day for Late Science Fair Projects is Friday

 Short video review on Punnett Squares  Review Questions for Stickers  Calculating Ratios from Punnett Squares  Independent Practice  Ink Think Article “Genes tell old Story”

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In humans, brown eyes (B) are dominant to blue eyes (b). 1.What are the possible phenotypes for eye color as listed above? 2.What would the be genotype of: a)a homozygous dominant human? b)A homozygous recessive human? c)A heterozygous human? 3.Which genotype(s) would code for brown eyes? 4.Which genotype(s) would code for blue eyes? 5.Draw a Punnett Square that crosses a homozygous dominant woman (BB) with a heterozygous man (Bb). What are the possible genotypes and phenotypes? 6.Draw a Punnett Square that crosses a heterozygous female (Bb) with a homozygous recessive male (bb). What are the possible genotypes and phenotypes? Review Questions for Stickers

 Why do we use Punnett Squares?  What does the term PUREBRED mean?  Where have you heard this term before?  Would PUREBRED BE HETEROZYGOUS or HOMOZYGOUS?  What does the term HYBRID mean?  Would HYBRID be HETEROZYGOUS or HOMOZYGOUS?  Any other questions from the video?

 For Monohybrid Crosses, the ratios are always going to occur in fourths, because there are four squares.  To Calculate the GENOTYPIC RATIOS, count the number of each GENOTYPE and put that over 4.  Example: The Genotypic Ratio in the figure to the right is: 1 BB to 2 Bb to 1 bb or 1:2:1 BBBb bb

 To Calculate the PHENOTYPIC RATIOS, count the number of each PHENOTYPE and put that over 4.  There are typically only two phenotypes for monohybrid crosses, the dominant & the recessive trait.  Example: The Phenotypic Ratio in the figure to the right is: 3 Brown to 1 Blue or 3:1 BBBb bb

 This is something you should be very familiar with from MATH class.  For monohybrid crosses, it is always going to be a factor of 25%, because there are 4 squares.  You can calculate the percentages based on the phenotype or genotype.  Example:  The genotype is 25% BB, 50% Bb, and 25% bb.  The phenotype is 75% brown, 25% blue. BBBb bb

Ff Question # 1 In Rabbits, Black Fur (F) is dominant to White Fur (f). Imagine you have a Homozygous Dominant Black Male Rabbit that you are going to mate with a Homozygous (FF) Recessive White Female Rabbit (ff). Draw the Punnett Square to predict the offspring. What is the genotype ratio? What is the phenotype ratio? Genotype Ratio: 100 % Heterozygous or Ff Phenotype Ratio: 100 % Black Fur

Ffff Ffff Question # 2 In Rabbits, Black Fur (F) is dominant to White Fur (f). Imagine you have a Heterozygous Black Male Rabbit (Ff) that you are going to mate with a Homozygous Recessive White Female Rabbit (ff). Draw the Punnett Square to predict the offspring. What is the genotype ratio? What is the phenotype ratio? Genotype Ratio: 50% Heterozygous (Ff) Rabbits to 50% Homozygous Recessive Rabbits (ff) Phenotype Ratio: 50% Black Rabbits, 50% White Rabbits

 Remember this from last week?  Underline or highlight things you want to remember or you deem important  Circle words you don’t know  ? Mark thinks you don’t understand  Attach the Passage in your Science Notebook.

In Rabbits, Black Fur (F) is dominant to White Fur (f). Imagine you have a Heterozygous Black Male Rabbit that you are going to mate with a Heterozygous Black Female Rabbit. 1.Draw the Punnett Square to predict the offspring. 2.What is the genotype ratio? 3.What is the phenotype ratio? My sister’s bunny, Basil Q. Hoppenfluff