2 Sexual & asexual reproduction offspring all have same genes (clones)Little to no variationFragmentation and buddingSexualgametes (sperm & egg) fertilizationmixing of genes variationBudding- small part that breaks off, hydra and yeastfragmentation breaking of parent into smaller pieces regeneration must occur then. Annelids, sea stars some fungus and plants does not mean that they do not reproduce sexually too, this is just a means for “emergency”4/14/2017
3 Parthenogenesis Egg development without a male contribution Wasps, honeybees, aphids, komodo dragons, some fish, frogs and lizardsUsually produces males4/14/2017
4 Mechanisms of sexual reproduction Fertilization(union of sperm and egg)externalinternalTimingCompatible copulatory organsAll species produce more offspring than the environment can handleSurvival???Pheromoneschemical signals that influence the behavior of others (mate attractants)4/14/2017
5 Reproductive hormones LH & FSHTestosteronefrom testesfunctionssperm production2° sexual characteristicsEstrogenfrom ovariesegg productionprepare uterus for fertilized eggtestes or ovaries4/14/2017
6 Sex hormone control in males HypothalamusGnRHPituitaryFSH & LHGonadotropin releasing hormoneTestestestosteroneBody cells4/14/2017
7 Male reproductive system Testicle (seminiferous tubules)Male reproductive systemspermspermatocytesTestes & epididymissperm production & maturationSperm productionover 100 million produced per day!~2.5 million released per drop!Glandsseminal vesicles, prostate, bulbourethalproduce seminal fluid = nutrient-rich (sugars)
8 Spermatogenesis Produce semen by age 7 Produce sperm by puberty (11-14 EpididymisTestisGerm cell(diploid)Coiledseminiferoustubules1°spermatocyte(diploid)MEIOSIS I2°spermatocytes(haploid)MEIOSIS IIVas deferensSpermatids(haploid)SpermatozoaCross-section ofseminiferous tubule4/14/2017
10 Female reproductive system Ovariesproduces eggs & hormonesUterusnurtures fetus; lining builds up each monthFallopian tubestubes for eggs to travel from ovaries to uterusCervixopening to uterus, dilates 10cm (4 inches) for birthing babyVaginabirth canal for birthing babyOvaries in a protective capsule with many follicles4/14/2017
11 Menstrual cycle Hypothalamus Pituitary Ovaries Body cells GnRH LHFSHHypothalamusegg developmentovulation = egg releaseGnRHcorpus luteumPituitaryFSH & LHestrogenAbout 450 cycles occur in a womans lifetime and then menopauseprogesteroneOvarieslining of uterusestrogenBody cells4/14/2017days7142128
12 Female hormones cells that used to take care of developing egg FSH & LHrelease from pituitarystimulates egg development (follicle) & hormone releasepeak release = release of egg (ovulation)Estrogenreleased from ovary cells around developing eggstimulates growth of lining of uteruslowered levels = menstruationProgesteronereleased from “corpus luteum” in ovariescells that used to take care of developing eggstimulates blood supply to lining of uterus4/14/2017
13 Egg maturation in ovary Corpus luteumproduces progesterone to maintain uterine lining4/14/2017
14 Oogenesis Unequal meiotic divisions unequal distribution of cytoplasm releaseOogenesisUnequal meiotic divisionsunequal distribution of cytoplasm1 egg2 polar bodiesCell stored in ovariesMeiosis 1 completedduring egg maturationCell matures in follicle on ovaryovulationMeiosis 2 completedtriggered by fertilization
18 Cleavage Repeated mitotic divisions of zygote 1st step to becoming multicellularunequal divisions establishes body plandifferent cells receive different portions of egg cytoplasm & therefore different regulatory signals
32 Apoptosis Programmed cell death Sculpts body parts Genetically programmed elimination of tissues & cells that were used for only short periods in embryo or adulthuman embryos develop with webs between toes & fingers, but they are not born that way!
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