| Question | Answer |
| Six characteristics that define an animal | 1. multicellular, heterotrophic
2. usually use sexual reproduction
3. no cell walls
4. motile for at least part of life
5. rapid response to external stimuli
6. diploid is dominant ploidy |
| blastocoel | cavity inside blastula |
| gastrula | fold in blastula due to gastrulation |
| blastopore | opening to pouch/archenteron |
| archenteron | internal cavity of gastrula |
| ectoderm | outer germ layer becomes skin and nervous tissue |
| endoderm | inner germ layer becomes digestive tract |
| mesoderm | middle germ layer becomes muscles and internal organs. primitive animals dont have this |
| lines of evidence that animals evolved from chanoflagellates (colonial protists) | 1. similarity in cells of choanoflagellates and sponges
2. choanocytes identified in other animal phyla but not in protists
3. DNA |
| Edicarian | x |
| Cambrian Explosion which phyla appeared (5) | Echinoderms, chordates, porifera, cnidaria, arthropoda. Hard bodies evolved in response to predation. |
| define cephalization | concentration of neurons in one region |
| Which is the only diploblastic phylum? | Cnidarians |
| Coelom | body cavity for development of internal organs. it is lined by mesoderm |
| pseudocolomates | body cavity but it is lined only on one side by mesoderm |
| name two pseudocoelomate phyla | rotifera and nematoda |
| Protostome: type of cleavage? determinate or indeterminate growth? fate of blastopore? | spiral, determinate, blastopore becomes mouth |
| Deuterostome: type of cleavage? determinate or indeterminate growth? fate of blastopore? | radial cleavage, indeterminate, blastopore becomes anus |
| Points of agreement in animal systematics: (5) | 1. all animals share a common colonial flagellate (choanoflagellate) ancestor
2. sponges are basal (the lowest form)
3. emetazoa - clade includes all animals with true tissues
4. most animals are bilateral
5. deuterostomia |
| Bilateral animals split into three groups: | deuterostomia, lophotrochozoa, echydsozoa |
| Define Lophotrochozoa | have either a lophophore (apical tuft of feeding cilia) or larval stage called a trochophore |
| Define Ecydsozoa | external skeletons that shed as they grow |
