Phylum Nematoda Phylum Annelida Phylum Mollusca Defining ...

Phylum Nematoda -roundworms -complete digestive system

Phylum Annelida -metamerism (segmented) -setae -well-developed organsystems

Phylum Mollusca -soft bodies -one or more shells -3 parts: head, foot, visceral mass -mantle -radula-rasping tongue

Symmetry Coelom Level of Organization Nervous

bilateral pseudocoelomate organ-system

bilateral coelomate organ-system

bilateral coelomate organ-system

-ganglia -nerve cords -sense organs

-ganglia -ventral nerve cord with segmental ganglia -sense organs

-ganglia -nerve cord -sense organs

Skeletal

hydrostatic skeleton

hydrostatic skeleton

-hydrostatic skeleton -shell

Muscular

longitudinal layer of muscles

circular layer and longitudinal layer

-mantle -muscle contractions in foot

Digestive

complete: complete: mouthÆintestineÆanus mouthÆpharynxÆ esophagusÆcropÆ gizzardÆintestineÆanus

Defining Traits

complete: mouthÆesophagusÆ stomachÆintestinesÆ anus digestive gland

Respiratory

diffusion

diffusion through cuticle gills

gills or lungs

Phylum Nematoda distribution through coelomic fluid

Phylum Annelida closed system with 5 pairs of aortic arches

Phylum Mollusca open system with heart, blood vessels, and sinuses

Excretory

excretory tubules and pores

nephridia

nephridia or simple kidney

Reproduction

-sexual reproduction -distinct sexes -external or internal fertilization

-hermaphrodites with sexual reproduction -external fertilization

-sexual reproduction -distinct sexes or hermaphrodites -external fertilization

1.Oligochaetaearthworms 2.Polychaeta-tube worms, marine worms 3.Hirudinea-leeches

1.Gastropoda-snails, slugs, nudibranchs 2.Bivalvia-clams, oysters 3.Cephalopoda-octopus, squid, nautilus, cuttlefish

Circulatory

Classes

Miscellaneous

-non-living cuticle for -burrowing may have outer covering saved the planet from -most are free-living, global ice age some are parasites -important decomposers

-siphons: incurrent and excurrent