1. Chapter 4: Chapter 4: Patterns of Heredity Section 1: Living things inherit traits in patterns.

2. Inherited Traits Traits passed down from your parents Traits passed down from your parents Genetically linked Genetically linked

3. Acquired Traits Something gained or learn during your lifetime Something gained or learn during your lifetime Not genetically linked Not genetically linked

4. Acquired traits Inherited Traits Combination of Both Learning to Snap Eye color Diabetes

5. Heredity is the passing of genes from parents to offspring These genes code for the expression of traits. an organism does not inherit the traits ONLY the genes for the traits Some characteristics are affected by many genes in complicated ways.

6. Homologs Most eukaryotic cells contain pairs of chromosomes, with one chromosome of each pair coming from each of two parents. The chromosomes in a pair are called homologs. They resemble each other, having the same size and shape, and carrying genetic information for particular traits. alleles a gene

7. Alleles An alternate form of a gene for a specific trait or gene product. Ex) in the picture A or a are different alleles for the same gene Ex) Tongue roller and non-tongue roller are different alleles for people alleles a gene

8. Gene The basic unit of heredity that consists of a segment of DNA on a chromosome. Are sites that code for particular traits such as eye color, hair color, etc. alleles a gene

9. Each species has a characteristic number of chromosomes. Chimpanzees have 24 pairs of chromosomes (48 total) Chimpanzees have 24 pairs of chromosomes (48 total) Fruit flies have 4 pairs of chromosomes (8 total) Fruit flies have 4 pairs of chromosomes (8 total) Humans have 23 pairs (46 total) Humans have 23 pairs (46 total)

10. What’s special about the 23 rd pair? The 23rd pair are the sex chromosomes. In humans, the sex chromosomes are called the X- chromosome and the Y-chromosome. A human female = XX A human male = XY

11. Phenotype vs. Genotype Describes the actual characteristics that can be observed P for Picture of what the genes “look” like Ex.) Brown hair, Blue eyes The name for the genes an organism has. Describe an organisms specific alleles Ex.) Aa, AA, aa

12. Dominant vs. Recessive More prominent, more powerful, stronger alleles More prominent, more powerful, stronger alleles Usually represented by a capital letter Usually represented by a capital letter Only needs 1 allele to control the phenotype Only needs 1 allele to control the phenotype Has the power to mask (hide) recessive alleles Has the power to mask (hide) recessive alleles Less prominent, less powerful, weaker alleles Less prominent, less powerful, weaker alleles Usually represented by a lower case letter Usually represented by a lower case letter Needs 2 alleles to control the phenotype Needs 2 alleles to control the phenotype Can not mask dominant alleles Can not mask dominant alleles

13. Homozygous vs. Heterozygous Having 2 of the same alleles in the genotype Having 2 of the same alleles in the genotype BB – Homozygous Dominant BB – Homozygous Dominant bb – Homozygous recessive bb – Homozygous recessive Also known as a PURE BREED Also known as a PURE BREED Having 2 different alleles in the genotype Having 2 different alleles in the genotype Bb – Heterozygous Also known as a HYBRID Also known as a HYBRID

14. Gregor Mendel A monk, trained in science and math, who lived in Austria during the mid- 1800s Performed the first major experiments investigating heredity Began investigating the inheritance of traits among the pea plants in the his garden Separately worked with seven different traits: plant height flower and pod position, seed shape, seed color, pod shape, pod color, and flower color.

15. Mendel Experiments Mendel noticed variations in the heights of pea plants So he purposely crossed (mated) pea plants that were pure-breed dwarf & pure-breed regular to see what their offspring would become Regular x Dwarf T T x t t

16. First generation (F 1 ) After crossing a true- breeding regular pea plant with a true- breeding dwarf pea plant all regular pea plants were produced in the first generation. Two of these plants were then crossed to produce a second generation F 1 generation all regular (Tt)

17. Second generation (F 2 ) After allowing the first generation pea plants to cross ¾ regular pea plants (TT & Tt) and ¼ dwarf pea (tt) plants were produced 1 Regular (TT), 2 Regular (Tt), & 1 Dwarf (tt) were produced

18. So What?!? Mendel drew upon his knowledge of mathematics while analyzing his data in order to suggest a hypothesis that would explain the patterns he observed.Mendel realized that each plant must have two “factors” for each possible trait, one factor from each parent. Some traits, such as dwarf height, could be masked—dwarf height could be seen in the

19. Chapter 4: Chapter 4: Patterns of Heredity Section 2: Patterns of heredity can be predicted

20. Punnett Square Illustrates how the parent’s genes can possibly combine Illustrates how the parent’s genes can possibly combine

21. Ratio Compare 2 different quantities (numbers) Compare 2 different quantities (numbers) Ex) Ratio of boys to girls = 10 to 7 or 10:7 Ex) Ratio of boys to girls = 10 to 7 or 10:7 # order depends on the wording # order depends on the wording

22. Probability The chance or likelihood of an event or something happening The chance or likelihood of an event or something happening

23. Percentage Compares the probability of something to 100 Compares the probability of something to 100 Ex) 93% of the questions on a test were correct Ex) 93% of the questions on a test were correct

24. Incomplete dominance Also known as “Co- dominance” Also known as “Co- dominance” Is when there are 2 different dominant alleles which share power Is when there are 2 different dominant alleles which share power Ex) RW = pink in poinsettias Ex) RW = pink in poinsettias

25. Dihybrid Crosses Deals with 2 genotypes at once Deals with 2 genotypes at once Includes 4 alleles Includes 4 alleles Brown Hair = B Brown Hair = B Blonde Hair = b Blonde Hair = b Brown eyes = Q Brown eyes = Q Blue eyes q Blue eyes q

26. BBQQBBQqBbQQBbQq BBQqBBqqBbQqBbqq BbQQBbQqbbQQbbQq BbQqBbqqbbQqbbqq BQ Bq bQ bq BQ Bq bQ bqGenoBBQQBBQqBbQQBbQqBBqqBbqqbbQQbbQqbbqqPheno Br hair & eyes Br hair & blue eyes Blonde & br eyes Blonde & blue eyes p Br & br 9/16 Br & bl 3/16 Bl & br 3/16 Bl & bl 1/16

27. Chapter 4: Chapter 4: Patterns of Heredity Section 4.3: Meiosis is a special form of cell division

28. Gamete Special cells that contain only half the number of chromosomes in a normal cell of that organism Special cells that contain only half the number of chromosomes in a normal cell of that organism Also known as “1n” cells, haploid or sex cells Also known as “1n” cells, haploid or sex cells In a female their gametes are referred to as eggs In a female their gametes are referred to as eggs In males, gametes are referred to as sperm In males, gametes are referred to as sperm

29. Body Cells Are normal typical cells Are normal typical cells Ex) skin, or muscle cells Ex) skin, or muscle cells Also known as “2n cells” or diploid cells Also known as “2n cells” or diploid cells

30. Fertilization The process that takes place when the egg and the sperm combine to form one new “2n cell” The process that takes place when the egg and the sperm combine to form one new “2n cell”

31. Meiosis Special kind of cell division that produces haploid cells Special kind of cell division that produces haploid cells Involves a single cell going through 2 divisions Involves a single cell going through 2 divisions Meiosis I & Meiosis II Meiosis I & Meiosis II

32. At the beginning of meiosis I, the parent cell has made two copies of each chromosome pair. During meiosis I, the homologs of the chromosome pair separate; there are two cells, each with two copies of one homolog from each pair. During meiosis II, the two copies of each homolog separate; each daughter cell has one homolog. Meiosis II 1n1n 1n1n 1n1n 1n1n Meiosis I How meiosis works…

33. Mitosis Meiosis Produces 4 daughter cells Produces 4 daughter cells Splits twice Splits twice Daughter cells have ½ the parents genetic info (DNA) Daughter cells have ½ the parents genetic info (DNA) Produces 1n cell, haploid cells, gamete or sex cells Produces 1n cell, haploid cells, gamete or sex cells Has 8 main stages Has 8 main stages Starts with a single cell Starts with a single cell Are forms of cell division Are forms of cell division Happens in stages Happens in stages Chromosomes (DNA) only copied 1 time Chromosomes (DNA) only copied 1 time Produces 2 daughter cells Produces 2 daughter cells Splits once Splits once Parent and daughter cells genetically identical Parent and daughter cells genetically identical Produces 2n cell, diploid cells or body cells Produces 2n cell, diploid cells or body cells Has 4 main stages Has 4 main stages