1. Genetics The study of heredity (how traits are passed on from generation to generation.)

2. Gregor Mendel the “father of Genetics” This monk tended the monastery gardens and noticed some of the different traits of the pea plants. Seed Shape Flower Position Seed Coat Color Seed Color Pod Color Plant Height Pod Shape Round Wrinkled Round Yellow Green Gray White Smooth Constricted Green Terminal Tall Short YellowGraySmoothGreenAxialTall

3. Selective Breeding Mendel manipulated the pea plants to selectively breed them. He would take pollen (carries the sperm) from one plant and brush it on the Stigma (female flower part) of another plant’s flowers. He made sure that the original plants we “true breeding” i.e.. Always produced the same traits when they were allowed to self pollinate.

4. P= parents F1= First generation F2= Second generation. Mendel crossed a tall pea plant with a short one and these were his results: P Generation F 1 Generation F 2 Generation TallShortTall Short

5. Genotype vs Phenotype The Genotype are the alleles that an organism has for a certain gene Often you can not tell what the genotype of an organism is for a certain trait by looking at it, (unless it is recessive, then it must be homozygous) The Phenotype is determined by an organism’s genes and how the environment has affected them =Genes + Environment The phenotype is how an organism expresses a trait. It is often what we can see.

6. The punnett square The punnett square can be used to figure out what the probability of the offspring having different traits.

7. Genotypes TT = Homozygous (Dominant) tt = Homozygous (Recessive) Tt Heterozygous (2 different alleles) Recessive traits “skip” Generations Only Express whey Homozygous Dominant genes are always express and mask recessive genes in heterozygotes

8. Genotype vs Phenotype Ratios Count how many of each Genotype 1 TT ¼ = 25% 2 Tt ½ = 50% 1 tt ¼ = 25% Count how many of each Phenotype 3 Tall ¾ = 75% 1 Short ¼ = 25%