Probability and The Punnett Square Gaiser Life Science

Know Evidence Page 37 Probability and The Punnett Square What are the chances of flipping a coin and landing on tails? Explain your answer. The Punnett Square

Clarifying ?s Information Page 38 probability - The chance/likelihood that something will happen - The chance/likelihood that something will happen - a chart that shows all possible genetic crosses - a chart that shows all possible genetic crosses Example: flipping a coin – 50/50 chance of landing on heads (50/50, 1 in 2, 1:1, ½, 50%) Example: Dad’s alleles = Tt, Mom’s alleles = TT Punnett Square - Mendel was the first scientist to determine that probability could be used to predict genetic crosses. used to determine the probability of a specific outcome Tt TTTtTt TTtTtT 25% 1 in 4 chance of a specific outcome Offspring has a 100% chance of being tall. Probability and The Punnett Square - Reginald C. Punnett originated the Punnett Square.

Clarifying ?s Information Page 39 Summary: - an organism’s genetic make-up - an organism’s physical appearance/visible traits - two identical alleles pheno = physical genotype phenotype homozygous Example: TT or tt Example: Tt heterozygous - two different alleles codominance - alleles are neither dominant or recessive – both show up in offspring Example: being tall Example: Tt Example: black chickens & white chickens – the offspring have both black and white feathers Probability and The Punnett Square

Page 38 Clarifying ?s Information Probability and The Punnett Square probability - The chance/likelihood that something will happen - The chance/likelihood that something will happen - a chart that shows all possible genetic crosses - a chart that shows all possible genetic crosses Example: flipping a coin – 50/50 chance of landing on heads (50/50, 1 in 2, 1:1, ½, 50%) Example: Dad’s alleles = Tt, Mom’s alleles = TT Punnett Square - Mendel was the first scientist to determine that probability could be used to predict genetic crosses. used to determine the probability of a specific outcome 1 in 4 chance of a specific outcome Offspring has a 100% chance of being tall. - Reginald C. Punnett originated the Punnett Square. Tt TTTtTt TTtTtT 25%

Page 39 Clarifying ?s Information Summary: Probability and The Punnett Square - an organism’s genetic make-up - an organism’s physical appearance/visible traits - two identical alleles pheno = physical genotype phenotype homozygous Example: TT or tt Example: Tt heterozygous - two different alleles codominance - alleles are neither dominant or recessive – both show up in offspring Example: being tall Example: Tt Example: black chickens & white chickens – the offspring have both black and white feathers

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