DO NOW!!! https://www.youtube.com/watch?v=aDp LDBaEBjk

Unit 2 Lesson 4

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

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

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

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

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

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

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

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

Activity: Elf Heredity Practice Worksheet

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

Example PP pp Pp Pp pp

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

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. https://www.youtube.com/watch?v=Mehz7tCxjSE T,F,F

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

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

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

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

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

Animation http://www.siskiyous.edu/class/bio1/geneti cs/monohybrid_v2.html

Activity: Punnett Square Worksheet

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

DO NOW!!! https://www.youtube.com/watch?v=cWt1 RFnWNzk

Investigating Traits Lab Activity

DO NOW!!! https://www.youtube.com/watch?v=j9ub0z1 -Q3o Complete Dominance & Incomplete Dominance https://www.youtube.com/watch?v=gouqTq5p168 Polygenetic Trait

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

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

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

Sickle Cell Anemia

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

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

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

Environments Influence Environment - influence organism’s phenotype. 40

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

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

Paper Pets Genetics Lab