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Sexual Reproduction. I just OOZE sex appeal!. I know, I look ridiculous!. Slug sex link. bird romance link. Biology of LOVE!. Sexual & asexual reproduction. Asexual offspring all have same genes (clones) no variation Sexual gametes (sperm & egg) fertilization
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Sexual Reproduction
I just OOZE sex appeal! I know, I look ridiculous! Slug sex link bird romance link Biology of LOVE!
Sexual & asexual reproduction • Asexual • offspring all have same genes (clones) • no variation • Sexual • gametes (sperm & egg) fertilization • mixing of genes variation
Parthenogenesis • Development of an unfertilized egg • honey bees • drones = males produced through parthenogenesis haploid • workers & queens = females produced from fertilized eggs diploid queen worker drone
Different strokes… gay penguins parthenogenesis in aphids “lesbian” lizards sex-change in fish
Hermaphrodites • Having functional reproductive system of both sexes earthworms mating flat worm
Fertilization • Joining of egg & sperm • external • usually aquatic animals • Development is metamorphosis • internal • usually land animals
Development • External • development in eggs • fish & amphibians in water • soft eggs= exchange across membrane • birds & reptiles on land • hard-shell amniotic eggs • structures for exchange of food, O2 & waste • sharks & some snakes • live births from eggs • Internal • placenta • exchange food & waste • live birth
Adaptive advantages? • What is the adaptive value of each type of sexual reproduction • number of eggs? • level of parental of care • habitat?
External Fertilization Sperm released into watery environment Eggs released into watery environment. Fertilization occurs in environment. # of sperm released? # of eggs released? Why? Internal Fertilization Sperm released inside female body (vagina). Eggs released into oviduct. Fertilization occurs in oviduct (aka?). # of sperm released? # of eggs released? Why? TONS! TONS! TONS! One (or few)
Other really weird organisms! marsupials monotremes
Reproductive hormones LH &FSH • Testosterone • from testes • functions • sperm production • 2° sexual characteristics • Estrogen • from ovaries • functions • egg production • prepare uterus for fertilized egg • 2° sexual characteristics testesorovaries
Sex hormone control in males Hypothalamus GnRH Pituitary FSH & LH Testes testosterone Body cells
Male reproductive system • Sperm production • over 100 million produced per day! • ~2.5 million released per drop!
Male reproductive system • Testicles • produces sperm & hormones • Scrotum • sac that holds testicles outside of body to regulate temperature • Epididymis • where sperm mature • Vas deferens • tubes for sperm to travel from testes to penis • Prostate, seminal vesicles, Cowper’s (bulbourethal) glands • nutrient rich fluid to feed & protect sperm • buffer to counteract acids in vagina
Spermatogenesis Testis Epididymis Germ cell (diploid) Coiled seminiferous tubules 1° spermatocyte (diploid) MEIOSIS I 2° spermatocytes (haploid) MEIOSIS II Vas deferens Spermatids (haploid) Spermatozoa Cross-section of seminiferous tubule
urinary bladder seminal vesicle prostate gland urethra penis rectum cowpers gland epididymus testis vas deferens scrotum Male Naughty Bits Review!
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 mature sperm. Vas Deferens: Carries sperm to the urethra and stores mature sperm Seminal Vesicles: secrete sugars and nutrients Bulbourethral glands: inject mucus Semen: a mix of sperm and nutrient containing fluid.
Sperm anatomy tail
Female reproductive system • Ovaries • produces eggs & hormones • Uterus • nurtures fetus; lining builds up each month • Fallopian tubes/oviduct • tubes for eggs to travel from ovaries to uterus • fertilization • Cervix • opening to uterus, dilates 10cm (4 inches) for birthing baby • Vagina • birth canal for birthing baby
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Girlie Parts & Jobs Ovaries: Produce & release mature eggs. Oviduct: carries egg to uterus, fertilization occurs here. Uterus: Site of embryo development. Vagina: Birth canal and site of sperm deposit.
LH Menstrual cycle FSH Hypothalamus egg development ovulation = egg release GnRH corpus luteum Pituitary FSH & LH estrogen progesterone Ovaries lining of uterus estrogen Body cells days 0 7 14 21 28
Meiosis 1 completed during egg maturation Meiosis 2 completed triggered by fertilization Egg production • Oogenesis • eggs in ovaries halted before Anaphase 1 • Meiosis 1 completed during maturation • Meiosis 2 completed after fertilization • 1 egg + 2 polar bodies unequal division ovulation What is the advantage of this development system?
Egg maturation in ovary • Corpus luteum • produces progesterone to maintain uterine lining
Menstrual Cycle revisited FSH: Stimulates the follicle to produce an ovum-(pituitary) LH: Causes ovulation (release of ovum)-(pituitary) Estrogen: Prepares the uterine lining-(ovary) Progesterone: Maintains the uterine lining for implantation-(ovary)
Female hormones • FSH & LH • release from pituitary • stimulates egg development & hormone release • peak release = release of egg (ovulation) • Estrogen • released from ovary cells around developing egg • stimulates growth of lining of uterus • lowered levels = menstruation • Progesterone • released from “corpus luteum” in ovaries • cells that used to take care of developing egg • stimulates blood supply to lining of uterus • lowered levels = menstruation