1. The passing of genetic traits from parent to offspring
Heredity
The passing of genetic traits from parent to offspring

2. Gregor Mendel – Father of Genetics
Austrian monk who studied patterns of inheritance in garden pea plants
Mendel controlled which plants pollinated other plants

3. Test corrections due today!!
What do you think the difference is between self-pollination and cross-pollination?
Test corrections due today!!

4. Gregor Mendel – Father of Genetics
Pollination in pea plants can either be:
Self-Pollination (where pollen from 1 plant lands on the same plant)
“True-Breeding” always produces offspring with traits that match the parent

5. Gregor Mendel – Father of Genetics
2. Cross-Pollination (where pollen from 1 plant lands on a different plant)
Occurs naturally from wind, water, animals, and bees
This method allowed Mendel to select what traits he could test

6. Mendel's Results First Generation Crosses Purple X Purple = Purple
White X White = White
Purple X White = Purple
Why were there no white flowers or pink flowers?

7. Second Generation Crosses
Mendel cross-pollinated 2 purple hybrid plants
The trait that had disappeared in the 1st generation always reappeared in the 2nd generation

8. Pg. 450 Table 1 “Mendel’s Results”
705 purple / 224 white
Ratio: 3.15:1
For every 3 purple flowers, there will roughly be 1 plant with white flowers
Pg. 450 Table 1 “Mendel’s Results”

9. Mendel's Conclusion
A genetic trait that is present is called a dominate trait
“The Big Guy”
A genetic trait that is not present and has “disappeared” is called a recessive trait
“The Little Guy”

10. Traits and Inheritance
Each parent gives one set of genes (instructions for an inherited trait) to offspring
Offspring get 2 forms of the same gene for every characteristic – one from each parent
These different forms (dominant and recessive) of a gene are alleles

11. Dominant allele = capital Recessive allele = lowercase
Genes affect an organism’s physical appearance or phenotype
Ex. flower color, seed texture
Inherited alleles together form the genotype
Dominant allele = capital Recessive allele = lowercase

12. An organism with 2 dominant or 2 recessive alleles is homozygous
Ex. PP or pp
An organism with 1 of each is heterozygous
Ex. Pp

13. Punnett Squares
Punnett square – chart where all possible gene combinations are shown in a cross of parents

15. Probability
Probability is the likelihood that something will happen