BIOL 202 Lecture Notes - Lecture 11: Amphioctopus Marginatus, Hydrostatic Skeleton, Symmetry In Biology
31 Jan 2016
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Document Summary
Coconut octopus uses shells to hide from predator. Cephalopods have 1mm thick neurons for increased speeds. 3 types of nervous cells: sensory neurons sensory stimuli, dendrites connecting, motor neurons muscle response. No myelination slower signals than vertebrates (1 m/s compared to. Starfish has unique nervous system separation of system for specific: brain functions. Baroreceptors sense water pressure (in copepods) Chromatophores: an organ, pigmenation in middle, glial cells protecting axons. No centralization of nerve cells for cognition. Reacts equally from all sides: cephalization. Concentration of nerve cells around sensory organs: bilateral symmetry, ganglion. Primitive nerve cord, more sophisticated processing: very receptive to evolution, hairs on silk moth antennae = chemoreceptors. Can detect 1 pheromone molecule from 1 trillion air molecules: beetles can detect chirality of molecules for coordinated ecosystem attack (sensitive and specific) Georeceptors sense gravity, orientation, acceleration: statocysts or air bubbles. Thermoreceptors: measures from 2 sides and compares dryer side to wetter side to, daphnia extremely sensitive to temperature.
