 Hello everyone. It's time for our Unit 1 review. In Unit 1 we started out with a timeline of genetics. The purpose of the timeline was to give you a good overview as far as what was discovered when and how the field of genetics evolved over time. We then talked about Gregor Mendel, who in fact is considered the father of genetics because of his discoveries. Remember, he focused on dominant and recessive traits. For example, flower color, where purple flowers were dominant to white flowers. He also discovered the principle of segregation. This principle is incredibly important because it means that the offspring will end up with the right number of chromosomes instead of doubling their chromosomes each generation. We also examined the principle of independent assortment. This is important because it's one of the main ways we have genetic variation in our offspring. We also covered the Punnett square, again which was invented by Reginald Punnett and is meant to be a teaching tool for Mendel's principles. We examined monohybrid crosses, which are crosses between two heterozygotes for one set of alleles, that's where the mono comes in. We looked at dihybrid crosses, again hybrid meaning heterozygos and di meaning two sets of alleles, and trihybrid crosses, where we were looking at heterozygotes for three sets of alleles. We also looked at the principles of probability. Remember, when you see the word and, you multiply, and if you see the word or, you add. We also looked at pedigrees in the inheritance of genetic diseases. We focused specifically on hemophilia, the royal disease, and finally we have our review. We hope that this has given you a good foundation to build upon for the next units.