Protostome Animals

lophotrochzoa

mouth forms first from blastopore, early cell differentiation, coelom forms via mesoderm splitting, bilateral symmetry

challenges of living on land

breathing, desiccation, movement/gravity, and gas exchange

desiccation

drying out

lophophore

ciliated feeding apparatus used for suspension feeding; ring of tentacles that pulls in food

trochophore

larval stage with apical cilia and ciliated central region

spiral cleavage

division of cells during embryonic development at an oblique angle; cells get smaller and smaller

platyhelminthes

flatworms

platyhelminthes characteristics

flattened bodies, coelom lost, gas/nutrient exchange over entire body, CNS, asexual/sexual, hermaphrodites, internal/external fertilization

hermaphrodites

female and male reproductive system

annelida

segmented worms

annelida characteristics

gas exchange over entire body, segmented body, coelom, complete digestive system, chaetae, some parapodia

chaetae

bristles- annelida synapomorphy

oligachaeta

few bristles, no parapodia, mobile, deposit feeders that aerate soil, hermaphrodites

polychaetae

many bristles on parapodia, mobile/sessile, predators, suspension feeders, scavengers

hirudinea

leeches

hirudinea characteristics

aquatic/mobile, many feeding strategies, hermaphrodites

mollusca

muscular foot, visceral mass, mantle

muscular foot

large muscle located at base of animal, used in movement

visceral mass

region containing main internal organs and external gill

mantle

outgrowth of body wall that covers visceral mass

mollusca characteristics

gills for respiration, coelom reduced, open circulatory system, CNS, sexual/asexual, internal/external fertilization, found in all environments

gastropoda

snails, nudibranchs, limpets, abalone

gastropoda characteristics

stomach foot; marine/terrestrial, some have shells, many feeding strategies

bivalvia

clams, oysters, mussels, scallops

bivalvia characteristics

two shells; foot modified for digging, suspension feeding using gills

polyplacophora

chitons, multiple plates

polyplacophora characteristics

8 hard plates/shells that overlap, radula used for grazing

radula

tongue with teeth, strengthened by iron

cephalopoda

cuttlefish, octopuses, squid

cephalopoda characteristics

foot modified in tentacles, beak used for biting (no radula), jet propulsion using modified mantle, reduced inner shell in some

ecdysis

molting for growth

exoskeleton

external structure

cuticle

a biological composite and non-cellular covering secreted by the underlying epidermal cells

ecdysozoa

grow via ecdysis, exoskeleton/cuticle, respiration strategies vary, reduced coelom, open circulatory system, sexual reproduction

nematoda

roundworms, ecdysozoa

nematoda characteristics

unsegmented, pseudocoelom, molt elastic cuticle, gas exchange across body, CNS

arthropoda

ecdysozoa, segmented bodies with joined appendages and tagma, chitinous exoskeleton, CNS, internal fertilization

jointed appendages

paired limbs- arthropoda synapomorphy

tagmata

fused segments- arthropoda synapomorphy

myriapoda

arthropoda, many- millipedes and centipedes; head and trunk, 1 pair antennae

insecta

arthropoda; 3 body segments (head, thorax, abdomen), 3 pairs of legs, 1 antennae, some have wings, mouthpart indicate feeding strategies, complete/incomplete metamorphosis

crustaceans

arthropoda; 3 body segments, appendages have diverse functions, 2 pairs antennae, mostly aquatic

chelicerates

arthropoda; 4 pairs walking legs, 2 body segments (cephalothorax, abdomen), no antennae, chilcerate and pedipalps for feeding