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24 Cards in this Set

  • Front
  • Back
Preformation v. epigenesis
gamete contains miniature preformed adult; animal emerges from a formless egg
fertilized egg
follows fertilization, creates blastomeres
holoblastic cleavage-complete division of egg, animals w/ less yolk
meroblastic cleavage-animal pole only cleavage, animals w/ more yolk
stage between 8-cell and blastula, "rasberry" stage
produced by cleavage, "hollow ball", blastocoel
produced by gastrulation and invagination; blastopore, archenteron, ectoderm, mesoderm, endoderm, yolk plug
germ layers
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,
amniote embryo
develop in a fuil-filled sac w/in shell or uterus, answer to dry environment reproduction
extraembryotic membranes
in amniotes; yolk sac, amnion, chorion, allotois
yolk sac
digest yolk to provide nutrients to embryo. vegetal pole, found below embryo in mammals
encloses embryo in a fluid filled sac that protects to embryo from drying out
cushions embryo
disposal sac for uric acid
multicellular, heterotrophic, eukaryotes, no cell walls, nervous tissue and muscle tissue
intermidiate stage, sexually immature, morphologically distinct from adult, undergoes metamorphosis
hypothesis for animal kingdom
colonial flagellated protist, choanoflagellates, hollow sphere colony
traditional phylogenic tree of animals
based mainly on structure and grades in body 'planes'
1st branch point
tissue: Parazoa (sponges)lack true tissue-barely animals, eumetazoa have true tissue
2nd branch point
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
3rd branch point
body cavity-
acoelmates-solid tissue, no cavity
psuedocoelmates-body cavity not enclosed completely by mesoderm
coelmates-have fluid-filled cavity completely surrounded by mesoderm
4th branch point
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
molecular based phylogenic tree
clashes w/ traditonal, differs in protostome branch with two clades lophotrochozoa and ecdysozoa
trochophore larva
animals that secrete the exoskeletons (molts old exoskeleton)