| A | B |
|---|
| this type of development has a larva stage | indirect development |
| young animal looks like an adult | direct development |
| inside skeleton | endoskeleton |
| integumentary system | skin |
| these organs remove ammonia from the body | kidneys |
| these organs exchange gases | lungs or gills |
| a hollow ball of cells | blastula |
| early divisions of the zygote forming more cells | cleavage |
| the cavity inside a blastula | blastocoel |
| infolded region of the blastula | blastopore |
| embryo with three cell layers | gastrula |
| this eventually forms the gut | archenteron |
| outer layer of cells in the gastrula | ectoderm |
| this layer of cells forms between the ectoderm and endoderm | mesoderm |
| this phylum has only two cell layers | cnidarian |
| this phylum doesn't have distinctive cell layers | porifera |
| egg and sperm form this structure | zygote |
| a body cavity lined by mesoderm | coelom |
| protostomes | blastopore becomes mouth |
| deuterostomes | blastopore becomes anus |
| archenteron | forms primitive gut |
| these phyla are protostomes | mollusks, arthropods, annelids |
| these phyla are deuterostomes | echinoderms and chordata |
| this type of cleavage forms identical twins | indeterminate |
| these animals have an acoelomate body cavity | flatworms |
| these animals have a pseudocoelom | rotifers and roundworms |
| most animals have this type of body cavity | coelomate |
| rigid outer body covering in arthropods and some mollusks | exoskeleton |
