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OVERVIEW

OVERVIEW. Reproduction is the creation of new individuals from existing ones A population can exceed its finite life spans by reproduction Adaptations of animal form and function will contribute to their reproductive success.

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OVERVIEW

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  1. OVERVIEW • Reproduction is the creation of new individuals from existing ones • A population can exceed its finite life spans by reproduction • Adaptations of animal form and function will contribute to their reproductive success

  2. 46.1: Both Asexual and Sexual Reproduction Occur in the Animal Kingdom • 2 Modes of Animal Reproduction • Asexual: genes of new individuals come directly from one parent • -relies on mitotic cell division • Sexual: new individuals created by the fusion of gametes to form zygotes • - Increases genetic variability of offspring • - Higher chance of reproductive success

  3. Asexual Reproduction of Sea Anemone Earthworms Mating Sexually

  4. Mechanisms of Asexual Reproduction • Fission: Parent separates into two or more individuals of equal size • Budding: New individuals arise from outgrowths of existing ones • Fragmentation: Body breaks down into multiple pieces-some or all of these pieces develop into adults - it requires regenerationof the lost body parts

  5. Hydra Budding • Video

  6. Fission in Amoeba Yeast Cells Budding Starfish using fragmentation

  7. Reproductive Cycles and Patterns • Reproductive cycles are controlled by hormonal and environmental cues • Parthenogenesis: process in which egg develops without fertilization Temperature Rainfall Lunar Cycles Parthenogenesis in Daphnia Eggs

  8. Cont.. • Hermaphroditism: each individual has male and female reproductive systems - some hermaphrodites self-fertilize • Sequential hermaphroditism: individual reverses its sex during its lifetime Lizard hermaphrodites Sex reversal in bluehead wrasse

  9. 46.2 Fertilization Depends on Mechanisms that help sperm meet eggs of same species • 2 types of fertilization -External: eggs shed by female are fertilized by sperm in external environment -Internal: egg and sperm unite in female body Inside female body External Fertilization frog • Fertilization requires environmental cues

  10. Ensuring the Survival of Offspring • Internal fertilization: produces less zygotes than external - but survival rate higher for internal fertilization • Parental care and protection of embryos results in few offspring by internal fertilization Male giant water bug carrying eggs

  11. Gamete Production and Delivery • Reproductive systems produce gametes and make them available to gametes of the opposite sex. • Simplest Reproductive systems do not have gonads (gamete producing organs) • Complex systems- accessory tubes and glands to protect/nourish gametes Complex flatworm reproductive system

  12. 46.3 Reproductive Organs Produce and Transport Gametes: focus on humansFemale Reproductive Anatomy • External: human female has vulva, labia minora, labia majora, and clitoris • Internal: Vagina connected to uterus, which connects to two oviducts; 2 ovaries (female gonads) have follicles containing egg cells • Mammary glands present in male and female but only function in female Female Reproductive System

  13. Male Reproductive System • External structures: scrotum and penis - testes (male gonads), are in cool environments in scrotum - testes have hormone producing cells and seminiferous tubules leading to tip of penis(epididymis, vas deferens, ejac. duct, urethra)

  14. Male Reproductive System

  15. Human Sexual Response • 2 physiological reactions in both sexes: vascongestion-filling of tissue with blood myotonia- increased muscle tension • 4 phases of response: -excitement -plateau -orgasm -resolution

  16. 46.4 In Humans and other mammals, a complex interplay of hormones regulates gametogenesis • Oogenesis- female form of gametogenesis (production of gametes) • Spermatogenesis- maleform • Meiosis is essential to oogenesis and spermatogenesis • Differences: - oogenesis: cytokinesis is unequal-produces large ovum; spermatogenesis: starting cells become 4 sperms - oogenesis: cyclic; spermatogenesis: constant/continual

  17. The Reproductive Cycles of Females • Menstrual(Uterine) cycle: proliferative and secretory phase - caused by ovarian cycle • Female reproductive cycle is one integrated cycle • Reproductive cycle dependent on secretion of GnRH, FSH, and LH

  18. Hormonal Control of Male Reproductive System • Androgens (steroid hormones) from testes cause primary and secondary sex characteristics in males • Androgen secretion and productioncontrolled by hypothalamic and pituitary hormones

  19. 46.5In humans and other placental mammals, an embryo grows into a newborn in the mother’s uterus • Pregnancy (Gestation): carrying one or more embryos in the uterus • Human pregnancy: 38 weeks • Pregnancy time, in other species, correlates with body size and maturity of young at birth

  20. Conception, Embryonic Development and Birth • After meiosis and fertilization of egg, zygote becomes blastocyst • Human pregnancy: 3 trimeters - Baby develops with time - Urine contractions (parturition) causes birth • 3 stages of birth: dilation of cervix, expulsion, delivery of placenta

  21. Human Fetal Development Timeline

  22. Three stages of Labor

  23. Mother’s Immune Tolerance of Embryo and Fetus • Half embryo genes are from father: foreign to mother’s body • Trophoblast and placenta: protectembryo from rejection in mother’s body - release signal molecules - break down tryptophan - induce “death activator” protein (FasL)

  24. Contraception and Abortion • Contraception: prevention of pregnancy • Methods of contraception prevent -release of mature gametes -fertilization -implantation

  25. Modern Reproductive Technology • Helps • Detect any problems with developing embryo before birth • People have children through in vitro fertilization: oocytes mixed with sperms and incubated Ultra Sound

  26. Works Cited "Female Infertility." Mayo Clinic. Mayo Foundation for Medical Education and Research. Web. 23 Apr. 2012. <http://www.mayoclinic.com/health/medical/IM01237>. "Human Development." ROHAN Academic Computing. 2007. Web. 25 Apr. 2012. <http://www-rohan.sdsu.edu/dept/phil/fetal.htm>. "Science Clarified." Birth. 2006. Web. 24 Apr. 2012. <http://www.scienceclarified.com/Bi-Ca/Birth.html>.

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