Animal Diversity Study Guide

Heterotrophic

Consume other organisms for energy

Multicellular

Organisms composed of multiple cells, eukaryotic, with no cell walls

Blastula stage

A stage in development where most animals reproduce sexually

Radial symmetry

Symmetrical in multiple planes (e.g., jellyfish)

Bilateral symmetry

Symmetrical in one plane (e.g., humans)

Diploblastic

Organisms with two tissue layers (e.g., cnidarians)

Triploblastic

Organisms with three tissue layers (e.g., flatworms, vertebrates)

Acoelomate

No body cavity (e.g., flatworms)

Pseudocoelomate

Body cavity not fully lined with mesoderm (e.g., roundworms)

Coelomate

Body cavity fully lined with mesoderm (e.g., annelids)

Protostome

Mouth develops first (e.g., mollusks, annelids, arthropods)

Deuterostome

Anus develops first (e.g., echinoderms, chordates)

Porifera

Sponges: No symmetry or true tissues; filter feeders; milestone = multicellularity

Cnidaria

Jellyfish: Radial symmetry; stinging cells; diploblastic

Platyhelminthes

Flatworms: Bilateral symmetry, acoelomates, triploblastic

Annelida

Segmented worms: Coelomates, segmented

Arthropoda

Insects, spiders: Jointed appendages, exoskeleton

Echinodermata

Starfish: Radial symmetry as adults, deuterostomes

Chordata

Vertebrates: Notochord, dorsal nerve cord

Notochord

A characteristic that unites chordates

Dorsal, hollow nerve cord

A characteristic that unites chordates

Pharyngeal slits

A characteristic that unites chordates

Post-anal tail

A characteristic that unites chordates

Tunicates

Invertebrate chordates (Urochordata)

Lancelets

Invertebrate chordates (Cephalochordata)

Lamprey

A vertebrate craniate without jaws

Pharyngeal slits modifications

Can be modified for filter feeding, gas exchange (gills), jaw and ear structure