1. Mendel’s Laws of Heredity Why we look the way we look...

2. What is heredity? Heredity: passing of characteristics (traits) from parents to offspring Genetics: the study of heredity

3. Gregor Mendel The first person to predict how ______ are transferred from parents to offspring. Called the “______ ___ _______.” Studied pea plants extensively

4. Why Study Pea Plants? 1.Reproduce sexually 2. They have both male and female sex cells (gametes) on the same flower. 3. Their traits are easy to isolate.

5. Mendel crossed them… Fertilization : the uniting of male and female gametes Cross : combining gametes from parents with different traits Mendel transferred pollen from plant to plant and studied the resulting offspring pea plants. Mendel removed the male parts of each flower to prevent uncontrolled pollination. Parent Generation F1 Generation

8. Mendel’s Conclusions?

9. 1. Law of Inheritance Inheritance is determined by factors passed from parents to offspring. Today these are called genes. The different forms of the same gene are called alleles. Example: one for black, one for tan, and one for white

10. 2. Principle of Dominance Some alleles are dominant, others are recessive. Recessive Traits - can be hidden whenever a dominant allele is present - represented with a lowercase letter * Dominant Traits -represented with uppercase letters -mask recessive traits

11. 3. Law of Segregation The two alleles for a trait must separate when gametes are formed A parent randomly passes only one allele for each trait to each offspring