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24 Cards in this Set
- Front
- Back
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Preformation v. epigenesis
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gamete contains miniature preformed adult; animal emerges from a formless egg
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Zygote
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fertilized egg
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Cleavage
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follows fertilization, creates blastomeres
holoblastic cleavage-complete division of egg, animals w/ less yolk meroblastic cleavage-animal pole only cleavage, animals w/ more yolk |
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morula
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stage between 8-cell and blastula, "rasberry" stage
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blastula
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produced by cleavage, "hollow ball", blastocoel
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gastrula
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produced by gastrulation and invagination; blastopore, archenteron, ectoderm, mesoderm, endoderm, yolk plug
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germ layers
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ectoderm-epidermis of skin, mouth lining, sense receptors in skin, cornea and eye lense, nervous system
endoderm-digestive tract, respiratory system, some organs mesoderm-notochord, skeleton, muscles, circulatory system, |
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amniote embryo
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develop in a fuil-filled sac w/in shell or uterus, answer to dry environment reproduction
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extraembryotic membranes
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in amniotes; yolk sac, amnion, chorion, allotois
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yolk sac
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digest yolk to provide nutrients to embryo. vegetal pole, found below embryo in mammals
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amnion
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encloses embryo in a fluid filled sac that protects to embryo from drying out
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chorion
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cushions embryo
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allantois
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disposal sac for uric acid
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animal
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multicellular, heterotrophic, eukaryotes, no cell walls, nervous tissue and muscle tissue
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larva
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intermidiate stage, sexually immature, morphologically distinct from adult, undergoes metamorphosis
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hypothesis for animal kingdom
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colonial flagellated protist, choanoflagellates, hollow sphere colony
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traditional phylogenic tree of animals
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based mainly on structure and grades in body 'planes'
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1st branch point
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tissue: Parazoa (sponges)lack true tissue-barely animals, eumetazoa have true tissue
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2nd branch point
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body symmetry-radial v bilateral, which have ventral and dorsal/anterior and posterior. cephalization-concentration of sensory equipment at the anterior.
germ layers-bilateria and tripoblastic, radiata are dipoblastic |
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3rd branch point
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body cavity-
acoelmates-solid tissue, no cavity psuedocoelmates-body cavity not enclosed completely by mesoderm coelmates-have fluid-filled cavity completely surrounded by mesoderm |
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4th branch point
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development of blastopore
Protostome-bl'pore becomes mouth, spiral and determinate cleavage, schizocoelous (coela form from solid mass of mesoderm) deuterostomes- blastopore becomes anus, radial and indeterminate cleavage, entercoelum (from folds in archenteron), includes echinoderms and chordata |
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molecular based phylogenic tree
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clashes w/ traditonal, differs in protostome branch with two clades lophotrochozoa and ecdysozoa
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lophotrochozoa
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trochophore larva
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ecdysozoa
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animals that secrete the exoskeletons (molts old exoskeleton)
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