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2. Chapter Menu Lesson 1:Sexual Reproduction and Meiosis Lesson 2:Plant Reproduction Lesson 3:Animal Reproduction Lesson 4:Asexual Reproduction Click on a hyperlink to view the corresponding lesson.

3. 3.1 Sexual Reproduction and Meiosis sexual reproduction egg sperm fertilization zygote meiosis diploid haploid

4. 3.1 Sexual Reproduction and Meiosis What is sexual reproduction? • Reproduction in organisms produces new offspring. • Sexual reproduction is the production of an offspring that results when the genetic materials from two different cells combine.

5. 3.1 Sexual Reproduction and Meiosis What is sexual reproduction? (cont.) • Half the genetic material in sexual reproduction is contained in: • an egg cell • a sperm cell • In a process called fertilization, the sperm and egg cells fuse together forming a zygote.

6. What is sexual reproduction? (cont.)

7. 3.1 Sexual Reproduction and Meiosis Advantages of Sexual Reproduction • Genetic variation • Variety of genetic traits in a population of the same species • Can help a species survive changes in environmental conditions

8. 3.1 Sexual Reproduction and Meiosis Advantages of Sexual Reproduction (cont.) • Selective breeding • Male and female organisms with certain preferred traits are selected to be the parents of offspring with those preferred traits • Produces groups of organisms with similar traits • Reduces genetic variation

9. 3.1 Sexual Reproduction and Meiosis Disadvantages of Sexual Reproduction • Getting egg and sperm together for fertilization can be difficult • Time is needed for organisms to grow and develop before they can reproduce

10. 3.1 Sexual Reproduction and Meiosis Why is meiosis important? • Meiosis is cell division that produces sperm or eggs from certain reproductive cells in an organism. • Meiosis ensures that a species’ offspring inherit the correct chromosome number. • Without meiosis, the chromosome number would double with each generation.

11. 3.1 Sexual Reproduction and Meiosis Maintaining Diploid Cells • A diploid cell in an organism contains pairs of homologous chromosomes that equal the chromosome number of that organism’s species. • A diploid human cell has 23 pairs of homologous chromosomes. • Homologous chromosomes are similar, but not identical.

12. 3.1 Sexual Reproduction and Meiosis Creating Haploid Cells • A haploid cell contains one chromosome from each homologous pair.

13. 3.1 Sexual Reproduction and Meiosis Phases of Meiosis I Prophase I—Nuclear membrane breaks apart and chromosomes condense. Metaphase I—Sister chromatids line up along the center of the cell. Cytoskeleton fibers attach to sister chromatids.

14. 3.1 Sexual Reproduction and Meiosis Phases of Meiosis I (cont.) Anaphase I—Sister chromatids move to opposite ends of the cell. Telophase I—Nuclear membrane forms around each set of sister chromatids and the cytoplasm divides, forming two daughter cells.

15. 3.1 Sexual Reproduction and Meiosis Phases of Meiosis II Prophase II—Nuclear membrane breaks apart. Metaphase II—Chromosomes line up along the center of the cell.

16. 3.1 Sexual Reproduction and Meiosis Phases of Meiosis II (cont.) Anaphase II—Sister chromatids of each chromosome begin to separate and move to opposite ends of the cells. Telophase II—A nuclear membrane forms around each set of chromatids, and the cytoplasm divides.

17. 3.1 Sexual Reproduction and Meiosis Comparison of Meiosis and Mitosis

18. 3.1 Sexual Reproduction and Meiosis Lesson 1 Review What is the new cell that forms from fertilization called? A sperm B egg C haploid D zygote

19. 3.1 Sexual Reproduction and Meiosis Lesson 1 Review How many chromosomes from each homologous pair does a haploid cell contain? A one B two C three D four

20. 3.1 Sexual Reproduction and Meiosis Lesson 1 Review How many daughter cells are produced in meiosis? A one B two C three D four

21. End of Lesson 1

22. 3.2 Plant Reproduction spore pollen grain ovule seed angiosperm stamen anther filament pistil stigma style ovary pollen tube fruit

23. 3.2 Plant Reproduction What is alternation of generations? • Some organisms, including plants, have two life stages called generations. • One generation has primarily diploid cells, the other generation has only haploid cells. • Organisms that alternate between diploid and haploid generations have an alternation of generations.

24. 3.2 Plant Reproduction What is alternation of generations? (cont.)

25. 3.2 Plant Reproduction How do seedless plants reproduce? • Seedless plants, such as mosses and ferns, grow from haploid spores, not seeds. • Haploid spores that grow by mitosis and cell division into haploid plants. • Fertilization results in a diploid zygote that grows by mitosis and cell division into the diploid generation. • The diploid generation produces haploid spores by meiosis, and the cycle repeats.

26. 3.2 Plant Reproduction How do seed plants reproduce? • Most of the land plants that cover Earth grew from seeds—called seed plants. • There are flowerless seed plants and flowering seed plants. • The haploid generation is within diploid tissue. • Separate diploid male and diploid female reproductive structures produce haploid sperm and haploid eggs.

27. 3.2 Plant Reproduction The Role of Pollen Grains • A pollen grain forms from tissue in a male reproductive structure of a seed plant. • Pollination occurs when pollen grains land on a female reproductive structure of a plant of the same species.

28. 3.2 Plant Reproduction The Role of Ovules and Seeds • The female reproductive structure of a seed plant contains one or more ovules. • After fertilization, a seed develops from the ovule.

29. 3.2 Plant Reproduction Flowerless Seed Plant Reproduction • In flowerless seed plants—gymnosperms— the seeds are not surrounded by a fruit. • Cones are the male and female reproductive structures of conifers. • Male cones produce pollen grains. • Female cones produce eggs. • Seeds form as part of the female cone.

30. 3.2 Plant Reproduction Flowering Seed Plant Reproduction • Flowering seed plants—angiosperms—include most of the plants you see. • Fruits and vegetables come from flowering seed plants. Seed Plants

31. 3.2 Plant Reproduction Reproduction and the Flower • A typical flower has male and female reproductive organs surrounded by petals. • The stamen is the male reproductive organ. • Pollen grains form at the tip of the stamen, in the anther. • The filament is a long stalk that supports the anther and connects it to the base of the flower.

32. 3.2 Plant Reproduction Reproduction and the Flower (cont.) • The female reproductive organ of a flower is the pistil. • Pollen can land at the tip of the pistil on the stigma,which is at the top of a long tube called the style. • At the base of the style is an ovarycontaining one or more ovules which eventually will contain a haploid egg.

33. 3.2 Plant Reproduction Reproduction and the Flower (cont.)

34. 3.2 Plant Reproduction An Angiosperm’s Cycle

35. 3.2 Plant Reproduction Fruit and Seed Dispersal • Fruits and seed are important sources of food for people and animals. • Fruits and seeds can be dispersed by: • Air currents • Animals • Water • Gravity What is the life cycle of a simple plant?

36. 3.2 Plant Reproduction Lesson 2 Review In alternation of generations, the haploid structures of the diploid generation produces daughter cells called what? A zygotes B spores C pollen D seeds

37. 3.2 Plant Reproduction Lesson 2 Review What is an immature diploid plant that develops from the zygote of a seed plant called? A embryo B seed C fruit D stigma

38. 3.2 Plant Reproduction Lesson 2 Review What is another name for a flowering seed plant? A zygote B conifer C gymnosperm D angiosperm

39. End of Lesson 2

40. 3.3 Animal Reproduction gonad testes ovary metamorphosis

41. 3.3 Animal Reproduction Animal Reproductive Organs • Gonads are specialized organs that produce sperm or eggs. • Testes are male gonads that contain a network of coiled tubes in which sperm cells form. • Ovaries are female gonads that produce egg cells.

42. 3.3 Animal Reproduction Internal Fertilization • Internal fertilization happens inside the body of an organism. • Internal fertilization ensures that an embryo is protected and nourished until it leaves the female’s body. • Examples • Earthworms, spiders, insects, reptiles, birds, and mammals

43. 3.3 Animal Reproduction External Fertilization • External fertilization occurs in the environment, outside of an animal’s body. • Most animals that reproduce using external fertilization do not care for the eggs or young. • Examples • Jellyfishes, clams, sea urchins, sea stars, many fish species, and amphibians

44. 3.3 Animal Reproduction External Embryo Development • Animals whose embryos develop outside the mother are usually protected inside an egg.

45. 3.3 Animal Reproduction Metamorphosis • A developmental process in which the form of the body changes as an animal grows from egg to adult

46. 3.3 Animal Reproduction Internal Development • The embryos of some animals, including most mammals, develop inside the mother. • A tissue or organ transfers nourishment from the mother to the embryo. • Other embryos—some snakes, insects, and fishes—develop in an egg with a yolk inside the mother.

47. 3.3 Animal Reproduction Gestation • Gestation is the length of time between fertilization and the birth of an animal. • Gestation varies by species and usually relates to the size of the animal at birth—smaller animals have shorter gestation.

48. 3.3 Animal Reproduction Lesson 3 Review Where are sperm formed in male animals? A eggs B ovaries C testis D glands

49. 3.3 Animal Reproduction Lesson 3 Review How is the embryo in an egg nourished? A the outer covering B an organ transfers nourishment from the mother C fluid produced in glands near the testes D the yolk

50. 3.3 Animal Reproduction Lesson 3 Review What is the developmental process in which the form of the body changes as an animal grows from egg to adult? A metamorphosis B gestation C fertilization D internal development