THE PROTOSTOMES MOLLUSCA ANNELIDA ARTHROPODA Radiata Parazoa no

THE PROTOSTOMES MOLLUSCA, ANNELIDA, ARTHROPODA

Radiata Parazoa no true tissues Bilateria Eumetazoa Multicellularity

PROTOSTOMES “mouth first” DEUTEROSTOMES “mouth second”

COMMON FEATURES Features # of germ layers type of symmetry body cavity fate of blastopore type of digestive system Mollusca Annelida Arthropoda triploblasts bilaterally-symmetric coelom present mouth develops first complete digestive system

DISTINGUISHING FEATURES Features Etymology Mollusca molluscus, “soft” soft-bodied General animals with description an external or internal shell # of species ~100, 000 spp. Annelida Arthropoda annellus “little ring” arthron + podos “joint foot” soft, segmented worms segmented body, tough exoskeleton, jointed appendages ~15, 000 sp. ~750, 000 sp. (highest sp. diversity)

MOLLUSK BODY PLAN • • muscular foot mantle calcium carbonate shell visceral mass http: //www. bio. miami. edu/dana/pix/ham. jpg, http: //kentsimmons. uwinnipeg. ca/16 cm 05/1116/33 -21 -Clam. Anatomy-L. jpg, , http: //images. encarta. msn. com/xrefmedia/aencmed/targets/illus/ilt/T 010708 A. gif

ANNELID BODY PLAN • metameres or segments • septa • setae or chaetae • sense organs

ARTHROPOD BODY PLAN • body segments • exoskeleton of protein + chitin • appendages that extend from the body wall

Phylum Mollusca (L. molluscus, “soft”) Feeding • herbivores, carnivores, filter feeders, detritivores, parasites • filter feeders: incurrent/excurrent siphon, mucus & cilia on gills • radula Respiration • aquatic: gills inside mantle cavity • terrestrial: constantly moist & highly vascularized mantle cavity Circulation Excretion Response Movement Reproduction • • • open circulatory system (snails, clams): sinus closed circulatory system (squid, octopuses) nephridia simple nervous system (bivalves) highly-developed nervous system (squid, octopuses) foot + mucus (snails) jet propulsion (octopuses) external fertilization (snails, bivalves) internal fertilization (cephalopods, some snails)

Phylum Mollusca Gastropoda snails and slugs Cephalopoda octopuses, squids, cuttlefish, Nautilus Bivalvia clams, oysters, mussels, scallops Scaphopoda tusk shells Aplacophora, Monoplacophora, Polyplacophora chiton

Feeding • herbivores, carnivores, filter feeders, detritivores, parasites • filter feeders: incurrent/excurrent siphon, mucus & cilia on gills in bivalves • radula in gastropods

Respiration • aquatic: gills inside mantle cavity • terrestrial: constantly moist & highly vascularized lung in mantle cavity

Circulation • open circulatory system (snails, clams): sinus • closed circulatory system (squid, octopuses) http: //chsweb. lr. k 12. nj. us/mstanley/outlines/circulation/Circulation_files/image 013. gif

Excretion • nephridia

Response • simple nervous system (bivalves) • highly-developed nervous system (squid, octopuses) http: //classconnection. s 3. amazonaws. com/754/flashcards/566754/png/49. 21320629922544. png

Movement • foot + mucus (snails) • jet propulsion (octopuses)

Reproduction • • external fertilization (snails, bivalves) internal fertilization (cephalopods, some snails) hermaphroditic, cross-fertilization trochophore larvae

Phylum Annelida (L. annellus, “ring”) • • Respiration • • Feeding Circulation Excretion Response Movement herbivores, carnivores, detritivores pharynx aquatic: through gills in their chaetae terrestrial: diffusion through moist skin • closed circulatory system (blood vessels and multiple hearts) • nephridia in each segment • highly-developed nervous system • terrestrial: contraction of longitudinal and circular muscles against the hydrostatic skeleton • aquatic: paddling of the parapodia Reproduction • asexual: fragmentation, budding in aquatic forms • • some hermaphroditic, cross-fertilization internal fertilization in most trochophore larvae in marine forms eggs in cocoons in terrestrial forms

Respiration • aquatic: through gills in their chaetae • terrestrial: diffusion through moist skin

Circulation • closed circulatory system (blood vessels and multiple hearts)

Reproduction • asexual: fragmentation, budding in aquatic forms • • some hermaphroditic, cross-fertilization internal fertilization in most trochophore larvae in marine forms eggs in cocoons in terrestrial forms

Phylum Annelida Oligochaeta earthworms, Tubifex Polychaeta bristle worms, sandworm, clamworm Hirudinea leeches

Phylum Arthropoda (G. arthron + podos, “joint foot”) Feeding • herbivores, carnivores, omnivores, bloodsuckers, filter feeders, detritivores, parasites • fangs, proboscis, sickle-shaped jaws, pincers • terrestrial: spiracles and tracheal tubes or book lungs in spiders • aquatic: feather-like gills in lobsters, crabs and book gills in horseshoe crabs • open circulatory system (heart blood vessels sinuses heart) • aquatic: diffusion • terrestrial: Malpighian tubules • highly-developed nervous system with brain, nerve cords, ganglia, and sense organs • well-developed muscle groups • exoskeleton Respiration Circulation Excretion Response Movement Reproduction • aquatic: internal/external fertilization

Phylum Arthropoda Crustaceans crabs, crayfish, lobsters, barnacles, shrimps Chelicerates horseshoe crab, ticks, spiders, mites, scorpions Uniramia centipedes, millipedes, insects Trilobita trilobites (extinct)

Feeding • herbivores, carnivores, omnivores, bloodsuckers, filter feeders, detritivores, parasites

Respiration • terrestrial: spiracles and tracheal tubes or book lungs in spiders • aquatic: feather-like gills in lobsters, crabs and book gills in horseshoe crabs

Circulation • open circulatory system (heart blood vessels sinuses heart)

Excretion • aquatic: diffusion • terrestrial: Malpighian tubules

Response • highly-developed nervous system with brain, nerve cords, ganglia, and sense organs