1. Why is reproduction an important life function?

2. Why is reproduction an important life function? Reproduction is the only life process that is optional for the organism, but essential for the survival of the species.

3. Unlike highly evolved organisms (e.g. Humans- who may choose when and where to reproduce)…….. Most organisms live to reproduce and to fulfill their niche in their habitat within an ecosystem.

4. Darwin’s “survival of the fittest” = the fitness of the individual to pass on their genetic information from one generation to the other. SUCCESSFUL REPRODUCTION

5. How does asexual reproduction differ from sexual reproduction?

6. Asexual Reproduction Involves the process of mitosis (2n) Before reproduction, there is a single organism. Following division, there is a genetically identical daughter organism that originated from the parent.

8. Sexual Reproduction Involves the process of meiosis (n) Begins with the fusion of male and female gametes to form a zygote Zygote is genetically different from the parents

9. Why is sexual reproduction more advantageous than asexual reproduction in the scope of evolutionary biology?

10. Why is sexual reproduction more advantageous than asexual reproduction in the scope of evolutionary biology? Sexual reproduction increases the genetic diversity of the offspring. Mutations may arise and can give one generation an adaptive advantage in the environment over the other generation.

11. Differences in Reproduction in the Animal Kingdom

12. Hydra

13. Phylum: Cnidaria- Reproduction Asexual bud forms & falls off parent polyp to become new polyp Sexual Medusa (14) releases egg & sperm into water fertilization in water to form zygote zygote develops into larva called planula (1) planula develops into polyp polyp develops to new medusa

14. Budding in Hydra

15. Platyhelminthes

16. reproductive system sexual- hermaphrodites both testes and ovaries, uterus in mesoderm layer cross- or self-fertilization asexual binary fission fragmentation and regeneration Phylum: Platyhelminthes

17. Class: Turbellaria Reproduction asexual by binary fission sexual- hermaphrodites cross-fertilization some mate by “penis-fencing” sperm injected in body wall fertilization and early development inside “mother” juveniles that resemble adult released

18. With mating in the flatworms……. there is a “Thin line between Love and Hate” Penis Fencing

19. long flat body made of many units called proglottids proglottid = complete reproductive unit with male and female gonads youngest proglottid behind head older proglottids w/ eggs shed in feces of definitive host reproductive output high many proglottids per tapeworm many eggs per proglottid Phylum: Platyhelminthes Class: Cestoda

21. Mollusks

22. Mollusks are hermaphrodites. Self-fertilization- only if no other mate is available. Cross-fertilization- is predominant form of reproduction.

23. Visceral mass Mantle Foot Coelom Intestine Gonads Mantle cavity Anus Gill Nerve cords Esophagus Stomach Shell Radula Mouth Nephridium. Excretory organs called nephridia remove metabolic wastes from the hemolymph. Heart. Most molluscs have an open circulatory system. The dorsally located heart pumps circulatory fluid called hemolymph through arteries into sinuses (body spaces). The organs of the mollusc are thus continually bathed in hemolymph. The long digestive tract is coiled in the visceral mass. Radula. The mouth region in many mollusc species contains a rasp-like feeding organ called a radula. This belt of backward- curved teeth slides back and forth, scraping and scooping like a backhoe. The nervous system consists of a nerve ring around the esophagus, from which nerve cords extend. Figure 33.16

25. Earthworm

28. Insects

29. Grasshopper Mating

30. Many insects – Undergo metamorphosis during their development In incomplete metamorphosis, the young, called nymphs – Resemble adults but are smaller and go through a series of molts until they reach full size

31. Insects with complete metamorphosis – Have larval stages specialized for eating and growing that are known by such names as maggot, grub, or caterpillar The larval stage – Looks entirely different from the adult stage

32. Metamorphosis from the larval stage to the adult stage – Occurs during a pupal stage Larva (caterpillar) (a) (b) Pupa (c) Pupa (d) Emerging adult (e) Adult

33. Transition from Water to Land

34. As organisms transitioned from water to land, the needs for fertilization and development had to change. Fluid was needed for flagellated sperm to find the egg to ensure fertilization. Water was needed to prevent the eggs from drying out on land.

35. External Fertilization vs. Internal Fertilization

36. External Development vs. Internal Development

37. Fish and Amphibians External Fertilization External Development

38. Frog Anatomy and Reproduction

39. Red-eyed Tree Frogs in Amplexus

40. External Development of Frog

41. Reptiles and Birds Internal Fertilization External Development

42. Internal Fertilization

44. Mammals Internal Fertilization Internal Development

45. Before we talk about internal development…… let’s tackle internal fertilization and the Human Reproductive System.

46. How do the structures of the Human Reproductive System enable the process of Sexual Reproduction*? *Sexual Reproduction entails internal fertilization and internal development

47. Male Reproductive Structures

50. It is important for the Scrotum to maintain cooler temperatures than body temperature. Why?

51. Viable sperm are temperature- dependent. Enzymes are sensitive to temperature and pH, including enzymes found in sperm.

52. Female Reproductive Structures

56. Now that we understand the structures that enable fertilization, let’s consider the Big Moment!

57. Copulation or Coitus

58. Fertilization

60. Embryonic development

61. Embryonic Germ Layers Diploblastic- 2 layers -ectoderm and endoderm -no mesoderm -ex. Cnidarians, Porifera (sponges) Triploblastic- 3 layers -ectoderm, mesoderm and endoderm -all animals with bilateral symmetry

62. Archenteron Blastopore Mesoderm Coelom Blastopore Mesoderm Coelom ectoderm -outer layer -forms animal’s outer covering, in some phyla central nervous system endoderm -inner layer -forms lining of digestive tract, in vertebrates forms liver, lungs mesoderm -between ectoderm/endoderm in triploblast -forms muscles between digestive tract and animal’s outer covering Embryonic Germ Layers

64. Embryonic Cleavage: Determinate (Protostomes) vs. Indeterminate (Deuterostome) In humans, the first few divisions are indeterminate. If cells in the embryo separate within the first divisions, the result is identical twins.

66. External Development vs. Internal Development

71. Let’s say this isn’t the right time for reproduction…….. Female Menstrual Cycle

74. Birth Control