Invertebrates

Jellies – Phylum Cnidaria

Round Worms – Phylum Nematoda Live in sediments or tissues of other organisms Over 12,000 described species (may be 500,000)Over 12,000 described species (may be 500,000) Very abundant (hundreds per mL of sediment)Very abundant (hundreds per mL of sediment) Hydrostatic skeletonHydrostatic skeleton

Peanut Worms – Phylum Sipuncula Unsegmented marine worms Borrow in mud, corals or empty shellsBorrow in mud, corals or empty shells Deposit feedersDeposit feeders

Peanut Worms – Phylum Sipuncula

Spoon Worms – Phylum Echiura Exclusively marine, unsegmented Non-retractable probiscisNon-retractable probiscis

Segmented Worms – Phylum Annelida Segmented worms Gut - coelom Hydrostatic skeleton Longitudinal and radial muscles Efficient locomotion and burrowing More than 15,000 species Cosmopolitan

Segmented Worms – Phylum Annelida Class Polychaeta 1. Class Polychaeta

Segmented Worms – Phylum Annelida Class Polychaeta 1. Class Polychaeta Diverse lifestyles Free-living predators Often well-developed eyes and sense organs, jaws

Segmented Worms – Phylum Annelida Class Polychaeta 1. Class Polychaeta Diverse lifestyles Burrowing deposit feeders Burrowing suspension feeders

Segmented Worms – Phylum Annelida Class Polychaeta 1. Class Polychaeta Diverse lifestyles Burrowing deposit feeders Burrowing suspension feeders

Phylum Mollusca

A.Body Structure

Phylum Mollusca RadulaRadula

Phylum Mollusca ReproductionReproduction Trocophore Veliger

Phylum Mollusca 1.Gastropods

Phylum Mollusca 1.Gastropods Nudibranchs with symbiotic algae Petropods

Phylum Mollusca 2.Bivalves Laterally compressed Two-valved shell No head or radula Gills used for suspension feeding (active) & respiration Water enters and leaves through siphons Some anchor to substrate with byssal threads