1. DO NOW!!!
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2. Unit 2 Lesson 4

3. What is heredity? (Pg. 124)
Traits - result from the information stored DNA
Heredity - passing of genetic material (traits) from parents to offspring. 3

5. Gregor Mendel (Pg. 124)
Austrian Monk – first to do experiments on heredity
Studied - seven characteristics of pea plants.
Characteristic - feature that has different forms in a population. 5

6. Seven Characteristics of Pea Plants
Flower Color
Flower Position
Seed Color
Seed Shape
Pod Shape
Pod Color
Stem Length (Height)
Each characteristic – 2 different forms - traits 6

7. Mendel’s Discoveries (Pg. 124)
Studied -each characteristic separately
Starting - with plants that were true-breeding.
True-breeding - always produce offspring with the same traits 7

8. Mendel’s Discoveries (Pg 125)
Crossed – a true breeding yellow seed pod plant with a true-breeding green seed pod plant.
P generation – Parent Plants
First generation (F1) – cross produced all green seed pods.
P Generation 8

9. Found that:
green seed pods = Dominant
yellow seed pods = Recessive g

10. Mendel's Discoveries (Pg. 125)
Crossed – 2 First generation (F1) green pod plants
Second generation (F2) – ¾ green seed pods & ¼ yellow pods. 10

11. Punnett Square
Recessive trait: yellow pod
disappeared in (F1)
reappeared in (F2)

12. Activity: Elf Heredity Practice Worksheet

13. Mendel's Discoveries
Hypothesized - each plant - two heritable “factors” for each trait – 1 from each parent
Two recessive factors = recessive trait.
One or two dominant factors = dominant trait.
Dominant trait still passes on both factors 13

14. Example PP pp Pp Pp pp

15. HW
Read pages 124 – 125 and complete question # 5 & 7.

16. DO NOW!!!
True or False
Siblings look similar because they each have some traits from their parents.
Siblings always have the same hair color.
Siblings have identical DNA.
T,F,F

17. Inhereted Traits (Pg 126)
Mendel hypothesized - each plant - two heritable “factors” for each trait – 1 from each parent
“factors” - segments of DNA - genes. 17

18. Genes (Pg. 126)
Give instructions – for producing a certain characteristics (Trait).
Offspring – 2 versions of same gene (trait) – 1 from each parent 18

19. Alleles (Pg. 126) Different versions of a gene (traits)
Dominant alleles - Capital Letter
Recessive alleles - lowercase 19

20. Allele Pairs for gene (Pg. 126)
1 dominant + 1 recessive = heterozygous
2 of the same alleles = homozygous 20

22. Genes Influence Traits (Pg. 127)
Combination of alleles from parents (genetic make up) - genotype.
Observable traits (what you look like) - phenotype. 22

25. Animation
cs/monohybrid_v2.html

26. Activity: Punnett Square Worksheet

27. HW
Read Pages 126 – 127 and complete questions and answer questions # 8, 9, & 11

28. DO NOW!!!
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29. Investigating Traits Lab Activity

30. DO NOW!!! https://www.youtube.com/watch?v=j9ub0z1 -Q3o
Complete Dominance & Incomplete Dominance
Polygenetic Trait

31. Complete Dominance (Mendel’s Genetics)
Cross – 1 parent (dominant + recessive alleles for trait) + 1 parent (dominant + recessive alleles for trait)
Phenotype – determined by dominant 32

32. Incomplete Dominance
Each allele – heterozygous - influences the phenotype.
Results - blend of the phenotypes of the parents.
Example:
1 allele - straight hair
1 allele - curly hair
= wavy hair 33

33. Polygenic Traits Characteristics - several genes acting together
Skin color
Eye Color
Hair Color 34

34. Pleiotropy Single allele - more than one effect.
Example – allele - turned a tiger white turned eyes being blue.
Example - genetic disorders (sickle cell anemia) - linked to a single gene - affect many traits.

35. Sickle Cell Anemia

36. Codominance
Both of the alleles inherited from parents - heterozygous individual - contribute to phenotype.
In both codominance and incomplete dominance, both alleles for a trait are dominant. In codominance a heterozygous individual expresses both simultaneously without any blending. 37

37. An example of codominance is the roan cow, which has both red hairs and white hairs.

38. Codominance Human blood type – 3 alleles A, B, O
A allele + B allele = type AB blood. 39

39. Environments Influence
Environment - influence organism’s phenotype. 40

40. Learned Traits Not inherited.
For example - ability to read and write is an acquired trait.

41. HW
Complete Table #19 on Page 131
Complete Lesson 4 Review on Page 133

42. Paper Pets Genetics Lab