Figure 32.8 phylogeny based on sequencing of SSU-rRNA

Chapter 7

Marine Without a Backbone

Invertebrates • • Characteristics of : – About 1 million species known, mostly marine – Most marine species are in a group of arthropods called – About 75% of all animals on are arthropods – Arthropods are very successful on land – - hard, but light and moderately flexible – Since the is external, an must shed the shell to be able to grow – process is called molting. There is a soft new shell underneath.


• Types of Marine Arthropods: • Crustaceans – 68,000 species – 2 pairs antennae – for respiration – and fused into a single unit called a ; entire external body is called the – Large array of specialized for different functions; ex: pinchers on , swimmerettes on the underside of hold developing , etc. – Types of crustaceans – , , Video of a and an – Types of crustaceans – copepods, barnacles, http://www.youtube.com/watch?v=tkz_SJv5RLM amphipods, isopods, crabs, shrimp, , etc. Barnacles - Ostracod Cirripedia • Shrimp-like but inside a bivalve “shell”

Isopods shrimp - Stomatopods

• Look like pillbugs, normally small • Second is a spear or club, special hard • http://www.youtube.com/watch?v=xeOSXt chitin BCY30 • http://www.youtube.com/watch?v=pgvsQ6 oNZyo


• Types of Marine Arthropods • Sea : – Four of more pairs of jointed – Not or true spiders – pycnogonids Invertebrates Invertebrates Invertebrates • Bryozoans • Characteristics of Phylum: • Types of Marine Arthropods – Small, colonial animals • Insects: – Some are encrusting forms, others form a branching network that looks like a small tree – Very few marine insects exist – Many insects feed in the at low tide, but these are just temporary visitors

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA Invertebrates

• Characteristics of Phylum: – Two shells or “valves ” enclose the body


• Arrow • Characteristics of Phylum: – 100 species, all marine – These organisms are planktonic, but slightly larger than most – They are voracious predators that are widely distributed in the marine – Grasping spines on head with – They will swim in rapid, darting movements to capture prey Invertebrates

• Deuterostomes • Characteristics of Phylum: – Name means "Spiny Skin" – Endoskeleton – Water vascular system with tube feet important in feeding and locomotion – Radial symmetry in adults - larvae are bilaterally symmetrical – is decentralized - no - this allows any portion of the body to lead – Can regenerate lost body parts – All 7000 species exclusively marine

Invertebrates • Types of Echinoderms • Sea cucumbers • Sea Urchins • Sea Stars


• The Phylum Chordata is a phylum that contains two groups, and , as well as many other, more familiar animals such as , , reptiles, birds and mammals. • Deuterostomes • Chordates have several features that are seen at least during some portion of the . Invertebrate Chordates

• Tunicates – sea squirts, salps

Invertebrate Chordates • Lancelets • Characteristics of Phylum: – 23 species – Very small, only up to 3 inches long – Body shows segmented muscle tissue

Choanoflagellate colony • Many body plans are now extinct • Only one found