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Unformatted text preview: Sheet1 Page 1 Final Exam Short Answer Questions 1. -Contrast internal vs external fertilization in animals. Both require: *coordinated timing to ensure fertilization ~environmental cues ~pheromones ~courtship behavior *sets of cells for ova and sperm &gt;gonads External- female releases eggs into the environment where the male fertilizes them *Moist habitat needed preventing gametes from drying out and allows sperm to swim to eggs *Timing is crucial to ensure eggs and sperm encounter each other &gt;spawning ~chemical signals from one individual releasing gametes triggers others to do same ~environmental cues &gt;mating behaviors &quot;courtship&quot; ~allows for mate selection and increases probibility of successfull fertilization *Release many gametes at once producing enourmous numbers of zygotes &gt;increases the chance that some will survive to adulthood Internal- Sperm is deposited in or near the female reproductive tract where fertilization occurs *Produce fewer offspring but exibit greater care of the embroys and young *Females may store sperm *More active choice of mates *Marsupials spend short amount of time in uterus, embroys crawl out and complete their development inside mother's pouch-What habitats and life history would favor evolution of internal fertilization? *adaptation enables sperm to reach egg efficiently *better for dry climates *requires cooperative behavior leading to the sex act *sophisticated and compatible reproductive systems ~Humans and placental animals have the placenta which nourishes the fetus durring fetal development from the mother's bloo ~elaborate reproductive systems with tubes and glands that carry and protect gametes ~mammals have a separate opening for the digestive tract, most females have separate opening for excetory and reproductiv ~deveopment of a well developed penis to ejaculate sperm inside female 2. How is information about the intensity of a stimulous communicated from a sensory receptor to the central nervous system *Many sensory nuerons spontaneously generate action potentials at a low rate. In these stimulous does not switch production 1. Sensory reception-detection of a stimulous by sensory cells-most include speciallized neurons or epithelial cells &gt;Sensory receptors: cells and organs that respond to specific stimuli like eyes and ears could also be a receptor that activates a nerve cell 2. Sensory transduction-conversion of a physical or chemical stimulous to a change in the membrane potential in a cell body &gt;Receptor potential: the change in membrane potential itself graded potentials whose magnitude varies with the stregth of the stimulous magnitude of a receptor potential controls the rate as which action potentials...
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