2. Sexual Reproduction

3. Overview: Sexual reproduction allows for greater genetic diversity in the hopes that at least some offspring will survive in a changing environment.

4. Girlie Parts & Jobs Ovaries: Produce & release mature eggs. Fallopian Tubes: carries egg to uterus, fertilization occurs here. Uterus: Site of embryo development. Vagina: Birth canal and site of sperm deposit.

5. Female Naughty Bits 1. 2a. 2b. Or…oviduct 3. 4. 5.

6. Same Bits, different view! See why pregnant women always have to pee?

7. Boy Parts & Jobs Testes: Produce Sperm Scrotum: Outer pocket of skin to keep testes cooler for ideal conditions for sperm development. Epididymis: A collection area for sperm. Vas Deferens: Carries sperm to the urethra (and picks up other secretions from the seminal vesicles to create semen). Semen: a mix of sperm and nutrient containing fluid.

8. Male Naughty Bits 1.Testes 2.Epididymis 3.Scrotum Penis 4.Urethra 5. Vas deferens6.7.Seminal Vesicle

9. External Fertilization Sperm released into environment (usually water). Eggs released into (watery) environment. Fertilization occurs in environment. # of sperm released? # of eggs released? Ex) invertebrates, insects, fish, amphibians. Why? Internal Fertilization Sperm released inside female body (vagina). Eggs released into fallopian tubes. Fertilization occurs in oviduct (aka?). # of sperm released? # of eggs released? Ex) Reptiles, bird, mammals (humans!) Why? TONS! One (or few)

10. Internal Fertilization: ● occurs in the upper portion of the ● a fertilized egg is called oviduct zygote ● cell division of a zygote by begins in the. 6-10 days later, the embryo implants in the ____________, where it will develop until birth. cleavage mitosis oviduct uterus Fraternal: 2 eggs and 2 sperm Identical: 1 egg + 1 sperm In vitro: test tube fertilization

12. Internal V. External Development

13. External Development Shell Embryo Air Sac Yolk* (good for dipping your toast!) Albumin (egg white) Allantois* (for gas exchange) * Both of these are filled with blood vessels running to and from the embryo. Chorion Amnion

14. Menstrual Cycle (females only!) FSH:Stimulates the follicle (in ovary) to produce an ovum. LH:Causes ovulation (release of ovum from ovary) Estrogen:Prepares the uterine lining for the embryo. Progesterone:Maintains the uterine lining for implantation of embryo.

15. ovary follicle ovum oviduct uterus cervix vagina sperm

16. Embryonic Development : 1. Cleavage: repeating mitosis forms a hollow ball of cells, no increase in size, just in cell number! 2. Blastula: A hollow ball of cells approximately the same size as the zygote (fertilized egg) 3. Gastrulation: One side of the blastula indents. 4. Differentiation: see next slide!

17. Differentiation: which cells become which structures? Ectoderm: Ectoderm: The outer part of the gastrula becomes the nervous system and epidermis of the skin. Mesoderm: Mesoderm: The middle of the gastrula becomes the muscles, skeleton, circulatory system, excretory system and reproductive system. Endoderm: The inner layer becomes the lining of the digestive tract, respiratory tract and the liver and pancreas.

18. What’s What?

19. linkYouTube - Amphioxus embryonic developmentYouTube - Amphioxus embryonic development (lancelet) – primitive chordate Cool Frog Eggs!

20. 6 weeks12 weeks18 weeks 24 weeks Gestation: time fetus develops in the uterus (40 weeks for humans) 36 weeks28 weeks

22. Internal Development Cervix Placenta1. Umbilical Cord2. Amniotic Sac3. Amniotic Fluid4. 5. 6.Fetus 7.Uterine Wall Oops! Same as # ? 8.Fallopian Tube (aka?)

23. Bovine Ovary Immature follicles Mature follicle Luteal scars Follicular cyst

24. Bovine Reproductive Tract: Left ovary Left Uterine horn What 2 organs are below the uterus? Cervix and vagina are out of the picture! Pregnant horn at early gestation Mind your own beeswax!

25. Bovine Reproductive Tract

26. Other really weird organisms!

27. And now you know about the birds and the bees………