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19 Cards in this Set
- Front
- Back
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what are the five stages of animal development?
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fertilization, clevage, gastrulation, neurulation, and organogenesis
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what is fertilization
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egg meets sperm
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what is clevage
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cell division (mitosis)
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what is gastrulation
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cells migrate and organize into specific structures (doesnt mean they stop mitosing)
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what is neurulation
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brain, spine, nervous system is created (still mitosing)
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what is organogenesis
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individual organs start to form
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what happens during fast block to polyspermy
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first sperm that hits egg will cause reverse of polarity on cell membrane and this repels other sperm
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what happens during slow block to polyspermy
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temporary buys time for slow permanent block --- when sperm releases nucleus in to egg. This triggers release of calcium in egg cell cytoplasm so no other sperm can ever enter
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does the organism increase size during clevage?
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no it increases in cell number but not cell size
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blastomeres
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half size daughter cell produced at each division
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blastula
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hollow ball of cells-- cells start to inc in size
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blastocoel
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space inside ball of cells
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what forms in endoderm during gastrulation
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digestive organs- forms epithelial lining of gut, liver, pancreas, lungs, and bladder
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what forms in the mesoderm during gastrulation
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forms heart, limbs, muscles, kidneys, blood, and connective tissues
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what forms in the ectoderm during gastrulation
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forms epidermis and nervous system (skin and scales), brain
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what is spina bifida, how can it be prevented
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failure of neural tube to close
if women take folic acid |
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what are homeotic genes
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conserved across species so developmental order is very similar in lots of other species
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what are morphogens
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substances eliciting cellular responses based on concentration
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morphogenic fields
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group of cells that ultimately produce a specific body structure.
genes are turned off/ on very early and will still have same function if removed and placed somewhere else |
