BIO 203 Lecture Notes - Lecture 21: Sequential Hermaphroditism, Sexual Reproduction, External Fertilization
7 Aug 2018
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In which an individual reverses its sex during its lifetime (e. g. carribean bluehead wrasse) Reproductive cycles: most animals (mammals) display cycles of reproductive activity, controlled by hormones and environmental cues (often related to seasons, reproduce when surplus energy is available (conserve resources, reproduce when conditions favor of offspring. 26. 2a: top: cartoon of human fetus at about 6 weeks of age, at this point, the fetus has both male and female internal reproductive structures, bipotential. Including kidneys and ureters: reproductive tracts, prostate glands, seminiferous tubules, then decision is made about its final anatomy. Important first step is the differentiation of the gonads: key step, sets everything else in motion, this is what the x and y chromosomes do, y chromosomes: sry gene, sex determining region of the y chromosome . In terms of direct genetic control, it"s only the differentiation of the gonads that is under direct genetic control: everything else is from the hormones, 2.
