Animalia

• dorsal side: back/top of an animal
• ventral side: underside/bottom of an animal
• anterior end: front/head end
• posterior end: back/butt end
• posterior end: back/butt end
• blastula: hollow ball of cells
• blastocoel: fluid-filled space inside the blastula
• gastrulation: the process that occurs in the early stages of embryonic development which the blastula folds inwards and enlarges to create a gastrula
• coelom: fluid-filled cavity or space found in some animals. separates gut from skin. it's function is to support and protect organs ("hydrostatic skeleton")
• gastrula: from the blastula and includes: ectoderm (outside skin), endoderm (inside skin), mesoderm (middle skin), archenteron (inside of gut), blastopore (mouth or anus)
• acoelomate (no coelom): no body cavity, mesoderm is solid without interior space, ex. phylum cnidaria, platyhelminthes
• pseudocoelomate: has a "false" body cavity, mesoderm lines interior of the coelom but does not line the outside of the endodermic gut, the endodermic gut is suspended in the fluid of the coelom, ex. phylum nematoda
• coelomates: has a true body cavity: mesoderm lines the coelom; surrounds and supports the endodermic gut, mesoderm forms tissues of attachment for organs in the gut such as the liver and pancreas. ex. phylum mollusks, annelida, arthropods, echinodermata, chordata
• Protostome (first mouth) (mollusks, arthropods, annelids): mouth develops from the blastopore, anus develops from the second opening
• Deuterostome (second mouth) (echinoderms and chordates): mouth developments from the second opening, anus develops from blastopore
• determinate (for protostomes): cells become specialized at the 8-cell stage, therefore, each cell will die if separated from the other cells
• indeterminate (for deuterostomes): cells become specialized after the 8-cell stage, therefore, each cell can continue development, and multiple embryos may result (ex. identical twins)
• indeterminate (for deuterostomes): cells become specialized after the 8-cell stage, therefore, each cell can continue development, and multiple embryos may result (ex. identical twins)
• schizocoely (for protostomes): gut body cavity; mesoderm forms from cells at the ectoderm and endoderm; mesoderm splits away and up towards interior of blastocoel; blastocoel disappears and mesoderm becomes lining for coelom
• enterocoely (for deuterostomes): gut body cavity; mesoderm forms from the cells at the part of the archenteron; mesoderm rolls out and down into the blastocoel; blastocoel disappears and mesoderm becomes lining for coelom
• germ layer: organization of specialized tissues
• cephalization: concentration of sensory organs at the anterior end (head)
• nervous tissue: respond to environment
• muscle tissue: allows animals to move
• neurons: send messages from brain to muscle