BIOPSYCH_3 - LECTURE 15 REPRODUCTION External fertilization...

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LECTURE 15 7/20/11 REPRODUCTION External fertilization; Internal fertilization- Oviparous (embryo inside egg) Viviparous (embryo inside placenta)-human Ovoviviparous (embryo develops inside egg, but inside the female)-sharks embryo DEVELOPMENTAL MODES --Altricial species: ex) songbirds-born with eyes closed, fed by parents, can’t hear etc. / Marsupials are extremely altricial --Precocial species; ex) chicken, reptiles, ducks, . . -not distinctions not clear, rather a spectrum -human classified as altricial species;require extenstive parental care-- but debated Species that are altricial could foster the ability to learn from conspecifics –evolution of particular behaviors Altriciality can provide platform for new behaviors to emerge (ex)songbird learning vocalization) ELABORATE DISPLAYS: to attract mate Peacock(long feather) Songbirds; bird of paradise (put on a show) Zebra finch(song)—crucial male zebra finch to attract female --Called, Apetitive behaviors - ZEBRA FINCH SONG -male to attract female songbird THE SONG SYSTEM -how sex steroids can give arise to sex differences in brain anatomy and behavior in song birds -brain of songbird: -illustration: highlighted are song nuclei interconnected within forebrain -nuclei critical to learn song during critical period and to produce that song in adulthood -there are number of species that are considered song birds -but birds in general, there are only 3 taxa that evolved the ability to learn vocalization; songbird, -only in the song bird do we find the song nuclei, the discrete nuclei in forebrain SEX DIFFERENCES IN SONG BIRDS -sex differences in brain anatomy and behavior -song nuclei much bigger in male= example of sexual dimorphism(there’s anatomical features are different between males and females) - SEX DIFFERENCES IN HUMANS -difference in size of cortex is shown between male and female -Regions that are thought to be bigger in male VS ~ in FM -in general, these differences do seem to be small in humans -ratio; (measure size of particular region vs. overall size) and compare FM and Male --problems: ex). In evolution when comparing species As brain get bigger isocortex get disproportionately bigger -predictable, but not isometrical scaling across mammalian brain -Not clear if using this ratio will lead us to wrong conclusion CRITICAL PERIODS FOR SONG LEARNING -sexual dimorphism in song nuclei in song birds
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-male songbirds learn song during critical period -Within 90 days after hatching the song crystalizes; song will not change much after critical period -For Zebrafinch During critical period there’s 1) Sensory phase; juvenile learn (listen) to male tutor(father) 2) sensorimotor phase; produces vocalizations, generally vocalizations that vary alot -eventually song no longer changes; it crystalizes. -if doesn’t learn song in critical period, it will produce a song that doesn’t look like typical male songbird
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BIOPSYCH_3 - LECTURE 15 REPRODUCTION External fertilization...

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