Lesson 18: Invertebrates Marine Biology

1. Lesson 18: Invertebrates Marine Biology

2. Invertebrates are animals that lack a backbone You may know many examples of these creatures that live in the ocean: jellyfish, sponges, corals, crabs Can you think of others? Spineless creatures Classification Overview Common Invertebrates Kingdom Animalia Phlyum Porifera Cnidaria Mollusca Arthropoda Echinodermata

3. Sponges: Phylum Porifera • Phylum: Porifera • Simple heterotrophs with two cell types: • Collar cells have flagella and draw water into the sponge’s central cavity (diagram right) • Epithelial cells line the sponge’s outer surface • Reproduce asexually by budding or sexually by release of sex cells (gametes) into the water • Filter feeders: feed by filtering suspended materials out of water The yellow tube sponge, purple vase sponge, red encrusting sponge and gray rope sponge Photo: NOAA Flagellum Collar cell

4. Phylum Cnidaria: The stinging nettles This purple striped jellyfish (Pelagiapanopyra) has a potent sting Photo: NOAA • Cnidarians include corals, anemones, sea fans, and jellyfish • Cnidarian characteristics: • Radial symmetry – they are symmetrical around a single point, like a clock • Two tissue layers separated by a jelly layer (mesoglea) • Nematocysts – structures on their tentacles that have stinging toxins Cnidarian Taxonomy Some Common Classes Kingdom Animalia Phylum Cnidaria Classes Anthozoa – anemones, Corals Scyphozoa – jellyfish Hydrozoa – fire corals, Portuguese Man-of-War

5. Some special Cnidarian species profiles Fire coral Class: Hydrozoa Order: Capitata These are in a different class than typical hard corals - you will get a mild burn if you touch them! Portuguese Man-of-War Class: Hydrozoa Order: Siphonophora These are in a different class than jellyfish, they are colonies – specialized polyps Photo: NOAA Photo: NOAA

6. Phylum Mollusca: Three defining traits • Mollusks include oysters, clams, mussels, conchs, snails, sea slugs, squid and octopuses • Most mollusks have three traits • Mantle: a muscular bag surrounding the gills and other organs for circulation • A muscular foot for movement • A radula: a rough scraping appendage for feeding or protection Mollusca Taxonomy Some Common Classes Kingdom Animalia Phylum Mollusca Classes Gastropoda – snails, sea slugs Bivalvia – clams, oysters, scallops, mussels Cephalopoda – squid, octopus

7. Some mollusks Photos: NOAA Foot Spiny oyster Class: Bivalvia Bivalves have two shells and no typical “head” like other mollusks Octopus Class: Cephalopoda The foot of the octopus is divided intoeight arms.

8. Phylum Athropoda: Superclass/Subphylum Crustacea Crustacean Taxonomy Some Common Classes Kingdom Animalia Phylum Arthropoda Subphylum Crustacea Classes Cirripedia – barnacles Copepoda – copepods Malacostraca – shrimp, lobster, crabs • Arthropods are land and sea “bugs” • Crustaceans include shrimps, crabs, lobsters, copepods and barnacles • About 1 million species exist • Crustacean characteristics: • Two pairs of antennae • Mandibles for chewing • Hard exoskeleton • Jointed legs

9. Some common crustaceans Photos: NOAA Rock lobster Sub-phylumCrustacea Class Malacostraca Order Decapoda Copepod Sub-phylumClass Crustacea Copepoda Order Harpacticoida

10. Phylum Echinodermata: The ocean’s stars Echinoderm Taxonomy Some Common Classes Kingdom Animalia Phylum Echinodermata Classes Asteroidea – sea stars Ophiuroidea – brittle stars Holothuroidea – sea cucumbers Echinoidea – sea urchins • Include sea stars (starfish), sea urchins, sand dollars and sea cucumbers • Most echinoderms have these traits: • Tube feet for motion • Radial symmetry (adults) • Symmetry around a single point • A water vascular system that circulates seawater

11. Some Echinoderms Sea urchin Phylum Class EchinodermataEchinoidea Source: NOAA Sunflower star PhylumEchinodermata Class Asteroidea Order Forcipulatida

12. Crustaceans supporting ecosystems • Copepods are tiny crustaceans and one of the most abundant forms of multicellular life in the ocean • Why do you think they might be important for marine food webs? • They are food for many different types of marine life including sea birds, small fish and whales • In this way, they are a very important part of marine ecosystems, providing a foundation for marine food webs

13. Some of the life supported by copepods Tuna Photos: NOAA Whale Shark Copepod Herring Auklet

14. Student activity • To figure out what types of organisms make up communities like the sample we just saw (and how many of each type there are), scientists use a process called sampling • In today’s activity, we will simulate different types of sampling methods to explore the variety of invertebrates in the ocean