1. Objectives 11.2 Applying Mendel’s Principles -Explain how geneticists use the Punnett square. -Explain the principle of independent assortment. -Explain how Mendel’s principles apply to all organisms.

2. Lesson Overview Lesson Overview Applying Mendel’s Principles Probability Probability is the likelihood that a particular event will occur.

3. Lesson Overview Lesson Overview Applying Mendel’s Principles Using Segregation to Predict Outcomes The principles of probability can be used to predict the outcomes of genetic crosses. Consistently, when crossing heterozygotes for a certain trait the 3:1 ratio came up in Mendel’s experiments.

4. Lesson Overview Lesson Overview Applying Mendel’s Principles Homozygous or Heterozygous ~ Organisms that have two IDENTICAL alleles for a particular gene -TT or tt - are said to be HOMOZYGOUS. ~Organisms that have two DIFFERENT alleles for a trait – Tt – are HETEROZYGOUS.

5. Lesson Overview Lesson Overview Applying Mendel’s Principles Genotype and Phenotype Every organism has genetic AND physical characteristics. The phenotype is the physical traits. The genotype is the genetic makeup.

6. Lesson Overview Lesson Overview Applying Mendel’s Principles Using Punnett Squares Punnett squares can be used to predict both the genotype and the phenotype of a particular organism, when the alleles are known, using probability.

7. Lesson Overview Lesson Overview Applying Mendel’s Principles Monohybrid or Dihybrid Cross??? When it involves two different genes, the experiment is known as a dihybrid cross. Single-gene crosses are monohybrid crosses.

8. Lesson Overview Lesson Overview Applying Mendel’s Principles