five-part radial symmetry with bilaterally symmetrical larvae
complete digestive tract
water vascular system with tube feet act as gills, sense organs, perform circulatory and excretory functions
predators, detritivores
chordates (lancelets, tunicates, hagfish, and vertebrates)
vertebrates share this clade with some invertebrates
four distinguishing features of chordates at some point of development: notochord, dorsal + hollow nerve cord, pharyngeal pouches or slits, postanal tail
cells
basic building blocks of the body
tissues
cells that interact and provide specific functions
organs
two or more interacting tissues
organ systems
two or more organs joined physically or functionally
epithelial tissue
cover body's internal and external surfaces with one or more layers of tightly packed cells
one surface exposed either to the outside or to a space within the body
opposite surface anchored to other tissues by a basement membrane
functions: protection, nutrient absorption, gas diffusion, secretion
epithelial tissue layers
simple, stratified, pseudostratified
epithelial tissue shapes
squamous, cuboidal, columnar
connective tissue
most variable tissue type
functions: fill spaces, attach epithelium to other tissues, protect and cushion organs, provide mechanical support