Chapter 33: Invertebrates Flashcards
main subclades of bilateria
protostomes and deuterostomes
main groups of protosomes
lophotrochozoa and ecdysozoa
lophotrochozoa
molluscs, annelids, flatworms, ectoprocts, trachiopods
ecdysozoa
arthropods, nematodes
invertebrates
animals that lack a backbone, account for over 95% of known animal species; morphologically diverse
porifera
sponges; least complex animals with no true tissues. Sister group to all other animals
hermaphrodites
same individual makes sperm and eggs
sponge sexual reproduction
spawn sperm to water, captured in another’s water current, captured by choanocytes
ostia
small pores of sponge that lead to spongocoel
spongocoel
big open internal space in sponges
osculum
big top opening in sponges
choanocytes
spongocoel lined by flagellated collar cells
feeding method of sponges
suspension feeders; filter/capture food particles from the water, captured by choanocytes
mesohyl
separation between inner and outer layer of cells of sponges
spongin
like collagen, may make up a proteinaceous skeleton for sponges
amoebocytes
move food around in sponges
cnidaria
“fancy gastrula”; radially symmetrical diploblasts with a gastrovascular cavity
gastrovascular cavity
mouth but no anus
alternation of generations
alternation of sexual and asexual generations; different taxa emphasize different phases
medusa phase
mouth-down, swimming, sexual stage (cnidaria)
polyp phase
mouth-up, sedentary, asexual stage (cnidaria)
cnidocytes
stinging cells of cnidaria
nematocyst
stinging organelle of cnidarias
lack of mesoderm implications
no true muscles; weak, contractile cells
hydrozoa, anthozoa, scyphozoa, cubozoa, staurozoa
diversity of cnidaria
bilateria
bilateral symmetry, have a head, triplobastic
protostomes
solid masses of mesoderm form, expand to filled blastocoel
deuterostomes
mesoderm buds of endoderm of archenteron
trochophore phylum
platyhelminthes: flatworms
annelida: segmented worms
mollusca: mollusks