October 17, 2014

1. October 17, 2014 • TO DO: Notebook, pencil/pen, sit with your group • WARM UP: What do you know about DNA? • HOMEWORK: • Weebly reflections for the whole week due 17/10

2. KEY CONCEPT Traits (characteristics) are inherited as discrete (separate) units

3. Before we begin… • Sit quietly for 30 seconds as you THINK!!!! • Think about this… • What are some traits you have that make you look like your mom or dad? If you don’t know what your mom or dad looks like, what are some qualities that make you look unique from the rest of your family? Or do you look more like one parent than another? • Why do you think this is???

4. Key Vocabulary Terms • Traits are distinguishing characteristics that are inherited (like hair color or blood type) • Genetics is the study of biological inheritance patterns and variation • Heredity: The passing of traits from parents to offspring

5. Background Information • In the 1800s, Gregor Mendel (an Austrian monk) made the first studies in predicting how traits would transfer from one generation to another • Many in Mendel’s day thought traits were blended …. A red flower and a white flower would make a pink flower

6. A. Mendel studied pea plants for 3 main reasons: • All the traits came in 2 easy to recognize forms • Both male and female gametes (sex cells) are produced on the same plant • The reproductive parts are tightly enclosed in petals preventing pollen from other plants entering

7. B. Fertilization • The uniting of male and female gametes (sex cells) • Plants “pollinate” • A hybrid plant would have one of each form of a trait

8. Think for a minute…- then pair/share • Have you ever heard of the term hybrid before???? • Def: the offspring of two animals or plants of different breeds, varieties, species, or genera, esp. as produced through human manipulation for specific genetic characteristics • Can you think of any examples of hybrids? • Livestock examples- • Yorkshire Pig x Hampshire Pig= Blue Butt • Black Angus x Hereford= Black Baldy • Thoroughbred x Arabian= Anglo Arabian

9. Mendel controlled the fertilization of his pea plants by removing the male parts, or stamens. He then fertilized the female part, or pistil, with pollen from a different pea plant.

10. B. Mendel’s 1st Experiments • Mendel’s 1st Experiments were called Monohybrid crosses (the plants were different by just one trait) • Example: all pea plants had purple flowers and green seeds, but some are tall and some short

11. B. Mendel’s 1st Generation • He crossed a pea plant that was pure purple flowers (it had only purple genes) with a plant that was pure for white (only white genes) • The offspring were all purple, no white pea flowers grew • The white trait seemed to disappear

12. C. Mendel’s 2nd Generation • Mendel crossed two of the offspring from the 1st generation • His results were 3 of every 4 plants were purple and 1 in 4 was white • The white trait reappeared

14. 3. Abbreviations • P1 = parent in the 1st generation • The offspring of P1 were called the F1 generation • “F” stands for filial • Filial stands for son or daughter • The offspring of the cross between 2 F1 plants were called the F2 generation

15. What disappeared in the 1st generation? • The trait for white • What reappeared in the 2nd generation? • The trait for white

16. Mendel observed patterns in the first and second generations of his crosses

17. D. Mendel’s Conclusions • Mendel concluded that each organism has 2 factors that control each of its traits • The factors controlling traits are called genes • One comes from each parent • They are found on the chromosomes • Genes exist in alternative forms

18. E. Law of Segregation: • During fertilization, the 2 different genes randomly pair to produce 4 different combinations of alleles • They separate independently

19. Law of Segregation Parents Tt Tt x T T Tt Tt tt Offspring

20. The Rule of Dominance Short plant Tall plant • Mendel called the observed trait dominant and the trait that disappeared recessive. • Mendel concluded that the allele for tall plants is dominant to the allele for short plants. t t T T t T F1 All tall plants t T

21. The Rule of Dominance Short plant Tall plant • When recording the results of crosses, it is customary to use the same letter for different alleles of the same gene. • An uppercase letter is used for the dominant allele and a lowercase letter for the recessive allele. • The dominant allele is always written first. t t T T t T F1 All tall plants t T

22. Phenotypes and Genotypes • The way an organism looks and behaves is called its phenotype. • The allele combination an organism contains is known as its genotype. • An organism is homozygous for a trait if its two alleles for the trait are the same. • An organism is heterozygous for a trait if its two alleles for the trait are different from each other.

23. The Law of Independent Assortment • Genes for different traits are inherited independently of each other. • Example: seed shape and seed color

24. Punnett Squares

25. homozygous vs heterozygous • an organism that is homozygous for a trait has two alleles for the trait that are the same. • an organism that is heterozygous for a trait has two different alleles (dominant and recessive).

26. punnett square • punnettsqaures are used to predict what possible offspring may be.

27. dihybrid cross