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1. Chapter Introduction Lesson 1 How are traits inherited? Lesson 2 Genetics After Mendel Lesson 3Adaptation and Evolution Chapter Wrap-Up Chapter Menu

2. How do species adapt to new environments over time? Chapter Introduction

3. What do you think? Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements. Chapter Introduction

4. 1. Genes are on chromosomes. 2. Only dominant genes are passed on to offspring. 3. Modern-day genetics disprove Gregor Mendel’s ideas about inheritance. 4. Mutations can cause disease in an individual. Do you agree or disagree? Chapter Introduction

5. 5. A population that lacks variation among its individuals might not be able to adapt to a changing environment. 6. Extinction occurs when the last individual of a species dies. Do you agree or disagree? Chapter Introduction

6. How are traits inherited? • How are traits inherited? • Why do scientists study genetics? • What did Gregor Mendel investigate and discover about heredity? Lesson 1 Reading Guide - KC

7. How are traits inherited? • genotype • phenotype • heterozygous • homozygous • heredity • genetics • selective breeding • dominant trait • recessive trait Lesson 1 Reading Guide - Vocab

8. From Parent to Offspring • Heredity is the passing of traits from parent to offspring. • Genetics is the study of how traits pass from parents to offspring. • For most organisms, genes are sections of DNA that contain information about a specific trait of that organism. Lesson 1-1

9. From Parent to Offspring(cont.) • A gene with different information for a trait is called an allele. • Each chromosome pair has genes for the same traits. • A gene’s alleles are in the same location on each chromosome of a pair. Lesson 1-1

10. How are traits inherited? • An organism passes its traits to its offspring in one of two ways—through asexual reproduction or through sexual reproduction. • In asexual reproduction, one organism makes a copy of its genes and itself. • In sexual reproduction, offspring receive half of their genes from an egg cell and the other half from a sperm cell. Lesson 1-2

11. How are traits inherited? Lesson 1-2

12. Why do scientists study genetics? • Scientists began studying genetics to understand how traits are inherited. • By studying genetics, scientists have learned that genes control how organisms develop. • Studying genetics can help scientists determine how organisms are related. Lesson 1-3

13. Because the genes from these organisms are similar enough to produce normal eyes when exchanged, scientists suspect that these species share a common, ancient ancestor. Lesson 1-3

14. Why do scientists study genetics? Lesson 1-3

15. Heredity—the History and the Basics • Selective breeding is the selection and breeding of organisms for desired traits. • In the illustration below, a farmer would breed the rooster with the hen that produces the most eggs per year. Lesson 1-4

16. Heredity—the History and the Basics (cont.) In 1856, Gregor Mendel began experimenting with pea plants to answer the question of how traits are inherited. Pixtal/age Fotostock Lesson 1-4

17. Heredity—the History and the Basics (cont.) Mendel chose plants that produced only green pods, called true-breeding, and crossed them with true-breeding plants that produced only yellow pods. Lesson 1-4

18. Heredity—the History and the Basics (cont.) • All the offspring, called hybrids, produced only green pods. • The yellow-pod trait seemed to disappear, not blend with the green-pod trait. • Mendel proposed that some traits of organisms are dominant, while others are recessive. Lesson 1-4

19. Heredity—the History and the Basics (cont.) • When Mendel crossed two hybrid plants with green pods, the cross resulted in offspring with green pods and offspring with yellow pods. • These offspring were in a ratio of about 3:1, green to yellow. Lesson 1-4

20. Heredity—the History and the Basics (cont.) • A dominant trait is a genetic factor that blocks another genetic factor. • A recessive trait is a genetic factor that is blocked by the presence of a dominant factor. • When an individual has one dominant allele and one recessive allele for a trait, the dominant trait is expressed. Lesson 1-4

21. Heredity—the History and the Basics (cont.) • The alleles of all the genes on an organism’s chromosomes make up the organism’s genotype. • How the traits appear, or are expressed, is the organism’s phenotype. Lesson 1-4

22. Heredity—the History and the Basics (cont.) phenotype from Greek phainein, means “to show”; and typos, means “type” Lesson 1-4

23. Heredity—the History and the Basics (cont.) • When an organism’s genotype has two different alleles for a trait, it is called heterozygous. • When an organism’s genotype has two identical alleles for a trait, it is called homozygous. Lesson 1-4

24. Heredity—the History and the Basics (cont.) What did Mendel investigate and discover about heredity? Lesson 1-5

25. Traits are passed from parent to offspring during asexual or sexual reproduction. • Through selective breeding, Mendel showed that some traits are dominant and some traits are recessive. Lesson 1 - VS

26. An organism’s genotype can be homozygous or heterozygous. • Each gene has two types of alleles, dominant or recessive. • A dominant allele is expressed over a recessive allele. Lesson 1 - VS

27. Which is a gene with different information for a trait? A. allele B. chromosome C. genotype D. offspring Lesson 1 – LR1

28. Which is a genetic factor that blocks another genetic factor? A. dominant trait B. genotype C. phenotype D. recessive trait Lesson 1 – LR2

29. Which is the process by which one organism makes a copy of its genes and itself? A. asexual reproduction B. genetics C. selective breeding D. sexual reproduction Lesson 1 – LR3

30. 1. Genes are on chromosomes. 2. Only dominant genes are passed on to offspring. Do you agree or disagree? Lesson 1 - Now

31. Genetics After Mendel • How can you use models to predict genetic outcomes? • What are the other patterns of inheritance? • What role can mutations play in the inheritance of disease? Lesson 2 Reading Guide - KC

32. Genetics After Mendel • multiple alleles • sex-linked trait • polygenic inheritance • pedigree • mutation • genetic engineering • monohybrid cross • Punnett square • incomplete dominance • codominance Lesson 2 Reading Guide - Vocab

33. Rediscovering Mendel’s Work • In 1900, scientists realized that genes were on chromosomes in the nucleus. • They confirmed that genes were Mendel’s dominant and recessive factors. Lesson 2-1

34. Predicting Genetic Outcomes • If you flipped a coin ten times, you might predict a heads-to-tails ratio of 5:5. • Probabilities are predictions; they do not guarantee outcomes. Your coin flips could result in ten heads in a row. Brand X Pictures Lesson 2-2

35. Mendel predicted the outcome of a monohybrid cross—a cross between two individuals that are hybrids for one trait. • Mendel predicted a 3:1 ratio of the dominant phenotype to the recessive phenotype. C Squared Studios/Getty Images Lesson 2-2

36. Predicting Genetic Outcomes(cont.) • A Punnett square shows the probability of all possible genotypes and phenotypes of offspring. • This Punnett square predicts that 75 percent of the offspring will express the dominant phenotype of green pods. Lesson 2-2

37. Predicting Genetic Outcomes(cont.) How does a Punnett square help scientists predict genetic outcomes? Lesson 2-2

38. Other Patterns of Inheritance When an offspring’s phenotype is a combination of its parents’ phenotypes, it is called incomplete dominance. Lesson 2-3

39. Other Patterns of Inheritance(cont.) When both alleles can be independently observed in a phenotype, it is called codominance. Nova Development Lesson 2-3

40. Other Patterns of Inheritance(cont.) • Human blood type is an example of multiple alleles, or a gene that has more than two alleles. • The IA and IB alleles are codominant to each other, but both are dominant to the i allele. Lesson 2-3

41. Other Patterns of Inheritance(cont.) • When the allele for a trait is on an X or Y chromosome, it is called a sex-linked trait. • In fruit flies, the allele for eye color is on only the X chromosome, not on the Y chromosome, Lesson 2-3

42. Other Patterns of Inheritance(cont.) • Some traits, such as height, are controlled by many genes. • Polygenic inheritance occurs when multiple genes determine the phenotype of a trait. 2007 Getty Images, Inc. Lesson 2-3

43. What are the other patterns of inheritance? Lesson 2-3

44. Inheritance of Disease • A pedigree shows genetic traits that were inherited by members of a family. • This illustration shows the pedigree for a family in which cancer was common in each generation. Lesson 2-4

45. Inheritance of Disease(cont.) • A mutation is any permanent change in the sequence of DNA in a gene or a chromosome of a cell. • If mutations occur in reproductive cells, they can be passed from parent to offspring. • Cancer, diabetes, and birth defects all result from mutations in genes. Lesson 2-4

46. Inheritance of Disease(cont.) mutation from Latin mutare, means “to change” Lesson 2-4

47. Inheritance of Disease(cont.) What role can mutations play in the inheritance of disease? Lesson 2-4

48. Inheritance of Disease(cont.) • Scientists today are using what they have learned about genetics to help people. • In genetic engineering, the genetic material of an organism is modified by inserting DNA from another organism. Lesson 2-4

49. Bacteria have been genetically engineered to produce human insulin. Lesson 2-4

50. Scientists use Punnett squares and pedigrees to predict and analyze genetic outcomes. Lesson 2 - VS