1. 10/30 Bell Work What do the following have in common?  Ichabod Crane  A missing head  Katrina van Tassel

2. 10/30 Schedule Ch 9 “Photosynth” test? Observe ovaries, anthers, and hydra Notes Ch 11.1 “Reproduction”

3. Ovaries, Anthers, and Hydra Up Close Observe the ovary or anther slides under the microscope. Compare/contrast the cells with the stages of mitosis. What percent of cells appear to be dividing? Observe hydra. Can you find any that have new ones budding off?

4. CH 11-12 OBJECTIVES: 1. DESCRIBE HOW GENETIC VARIATION OCCURS. 2. EXPLAIN HOW GENOTYPES LEAD TO PHENOTYPES. Unit : Meiosis and Genetic Variation

5. Ch 11.1 “Reproduction” Objectives: 1. Compare asexual and sexual reproduction. 2. Explain why chromosomes are important to organisms

6. A/sexual Reproduction!?! What is asexual reproduction? Name 3 kinds organisms that reproduce asexually. Name 3 kinds of organisms that reproduce sexually.

7. Asexual Reproduction Asexual reproduction = one parent passes its genetic information to each of its offspring.  Babies are genetically identical to the parent.  Example organisms  Binary fission in bacteria. binary fission

8. Asexual Reproduction Example organisms  Many unicellular eukaryotes also reproduce asexually.

9. Asexual Reproduction, continued Example organisms Some multicellular eukaryotes like starfish go through fragmentation. The body breaks into pieces regrow missing parts. Starfish regrowing its other 4 arms.

10. Asexual Reproduction, continued Example organisms Other animals like the hydra go through budding. New individuals grow and split off from existing ones.

11. Asexual Reproduction, continued Example organisms  Some plants, such as potatoes, can form whole new plants from parts of stems.  Other plants can reproduce from roots or leaves. strawberry runners potato eyes plant cuttings

12. Asexual Reproduction, continued Example organisms Some crustaceans like water fleas reproduce by parthenogenesis. A female makes an egg that grows into an adult without being fertilized by a male. It’s a girl! They all are.

13. Sexual Reproduction Most eukaryotic organisms reproduce sexually. There are two parents and the offspring are a genetic mix. Each parent produces a reproductive cell, called a gamete. A gamete from one parent fuses with a gamete from the other. Two gametes: Sperm and egg

14. Sexual Reproduction, continued Fertilization: sperm + egg = zygote  Offspring mixes traits from both parents.

15. Sexual Reproduction, continued Specialized Cells Germ cells: specialized for sexual reproduction. Only germ cells can produce gametes. Somatic Cells: all other body cells. They do not participate in sexual reproduction. gametes…sperm and egg

16. 11/2 Bell Work A watch was discounted 20% and then another 30% at the register during a sale. Would the price be lower if there was one discount of 50%? Why or why not? Hint: Assume the watch was $100.

17. 11/2 Schedule Ch 9 “Photosynth” test? Notes Ch 11.1 “Reproduction” Work on DR 11.1 Assignments: 1. Ch 11 Dir Rdg packet TBA

18. Sexual Reproduction, continued Advantages and Disadvantages of Asexual Reproduction Asexual reproduction is the simplest, most efficient method of reproduction. Organisms produce many offspring in a short period of time without using energy to make gametes or to find a mate. BUT…genetic information varies little between individuals, so they may be at a disadvantage in a changing environment.

19. Sexual Reproduction, continued Advantages of Sexual Reproduction Sexual reproduction produces genetically diverse individuals. Diverse population is more likely to have some individuals that survive a major environmental change. Typical environmental changes.

20. Chromosomes Details Each has thousands of genes that determine how an organism develops and functions. Each species has a specific number of chromosomes. An organism must have exactly the right number of chromosomes.

21. Chromosomes Example: Too many chromosomes  Klinefelter syndrome: Male is born XXY  Down’s Syndrome: 3 copies of Chromosome 21 Person with Klinefelters. Man with Down’s

22. Chromosomes Haploid and Diploid Cells Haploid: 1 set of chromosomes  Gametes are haploid. Diploid: 2 sets of chromosomes. Polyploid: > 2 copies

23. Chromosome Number, continued Haploid and Diploid Cells The symbol n is used to represent the number of chromosomes in one set.  Human somatic cells have 46 chromosomes (2n = 46).  Human gametes have 23 chromosomes, so n = 23.

24. Chromosome Number, continued Homologous Chromosomes Each diploid cell has pairs of chromosomes.  Homologous chromosomes: chromosomes that are similar in size, in shape, and in kinds of genes.  Each chromosome comes from one of the two parents.  Might be different forms of the gene.

25. Chromosome Number of Various Organisms Haploid number?

26. Chromosome Number, continued Autosomes and Sex Chromosomes Autosomes: chromosomes with genes that do not determine the sex of an individual. Sex chromosomes: chromosomes with genes that determine the sex of an individual.

27. Chromosome Number, continued Autosomes and Sex Chromosomes In many organisms, the two sex chromosomes are referred to as the X and Y chromosomes. The genes that cause a zygote to develop into a male are located on the Y. Human males are XY, and human females are XX.

28. Bacterial Calculations Bacteria split using mitosis. Imagine a bacteria divides every 15 minutes. 1. Figure out in your desk groups how many bacteria there would be in 6 hours. 2. Why isn’t the earth covered in bacteria?

29. Reproduction Diagram Create a Venn Diagram Compare/Contrast Sexual and Asexual Reproduction Include: Definition Examples

30. 11/3 Bell Work Duncan Drivel was asked how many ducks he had. “Well,” he said, “they just walked down the path and I didn’t actually count them, but I remember one duck in front of two ducks, another duck behind two ducks, and another duck between two ducks. What is the fewest number of ducks Duncan could have?

31. 11/3 Schedule Ch 9 “Photosynth” test? Notes Ch 11.2 “Meiosis” Meiosis Songs Work on DR 11.1 and 11.2 Assignments: 1. Ch 11 Dir Rdg packet TBA

32. Ch 11.2 “Meiosis” Objectives Compare and contrast meiosis with mitosis. Describe 3 mechanisms of genetic variation.

33. Introduction to Meiosis If a human sperm and egg each had 46 chromosomes, how many chromosomes would a fertilized egg have? Why might increasing the number of chromosomes a human cell cause problems?

34. Meiosis Square Dance Write these in your notebook. Before the video. Sketch and label the stages of mitosis During the video. 1. How is meiosis similar/different from mitosis? 2. What is crossing over? What is the result?

35. Stages of Meiosis Meiosis is a form of cell division that produces daughter cells with half the number of chromosomes.  A diploid cell divides 2x to form 4 haploid cells.

36. Stages of Meiosis 2 Stages  Meiosis I, homologous chromosomes are separated.  Meiosis II, the sister chromatids of each homologue are separated.

37. Stages of Meiosis, continued Meiosis I – Chromosomes already copied… Prophase I: chromosomes condense, and the nuclear envelope breaks down. Homologous chromosomes pair. Chromatids exchange genetic material by crossing-over..

38. Stages of Meiosis, continued Meiosis I Metaphase I: the spindle moves the homologous chromosomes to the equator.

39. Stages of Meiosis, continued Meiosis I Anaphase I: the homologous chromosomes separate. The spindle fibers pull the chromosomes of each pair to opposite poles.

40. Stages of Meiosis, continued Meiosis I Telophase I: the cytoplasm divides (cytokinesis), and two new cells are formed. Both cells have one chromosome from each pair of homologous chromosomes.

41. Stages of Meiosis, continued Meiosis II Meiosis II begins with the two cells formed at the end of telophase I of meiosis I. The chromosomes are not copied between meiosis I and meiosis II.

42. Stages of Meiosis, continued Meiosis II Prophase II, new spindles form. Metaphase II, the chromosomes line up along the equators and are attached at their centromeres to spindle fibers.

43. Stages of Meiosis, continued Meiosis II Anaphase II, the centromeres divide. The chromatids, which are now called chromosomes, move to opposite poles of the cell.

44. Stages of Meiosis, continued Meiosis II Telophase II, a nuclear envelope forms around each set of chromosomes. The spindle breaks down, and the cell goes through cytokinesis. The result is four haploid cells.

45. The Stages of Meiosis

46. Comparing Mitosis and Meiosis Mitosis and meiosis are similar but meet different needs and have different results. Purpose  Mitosis is used for growth, development, repair, and asexual reproduction.  Meiosis enables organisms to reproduce sexually and happens only in reproductive structures.

47. Comparing Mitosis and Meiosis, continued Results (in Humans and most animals)  Mitosis = 2 identical diploid cells.  Meiosis = 4 different haploid cells with half the genetic information of the parent.

48. Comparing Mitosis and Meiosis, continued Genetic Variation  In prophase I, chromosomes pair with its homologue and these chromosomes become a tetrad.  Homologues trade parts of their chromatids during crossing- over. Chromosomes do not pair up or cross over during mitosis.

49. Genetic Variation Existing genes are rearranged.  Crossing over  Chromosomes are sorted independently into one of the 4 daughter cells during Metaphase I.  Fusion of haploid cells from two different individuals. Independent assortment

51. “Strange” Reproduction Research  Define apomixis, parthenogenesis, hermaphrodism, and protogyny.  Give an example of organisms that use each kind of reproduction.  What are the benefits of each system? Checked tomorrow

52. Asexual Options Notecard If humans reproduced asexually…  Draw, label, and explain pictures showing what it would look like if humans reproduced by budding, fragmentation, and binary fission.

53. 10/30 Bell Work How can you stand behind your father while he is standing behind you?

54. 10/30 Schedule Check Reproduction Research Case of the Dividing Cell Work on DR 11.2 Assignments: 1.DR 11.2 due TODAY 2.“Strange” Reproduction Research due TODAY Quiz Ch 11.1-11.2 on FRIDAY