Lecture 11: Echinoderms

• Arthropod: Crustacea: Euphausiacea (krill)

  Have pleopods (used for movement) and Pereiopods (combs for food)
• Arthropod: Crustacea: Amphipoda

  5-15 mm

  Burrowers/live in tubes
• Arthropod: Crustacea: Copepoda

  The most abundant zooplankton
• Arthropoda: Crustacea: Cirrepedia (barnacles)

  Hace cirripeds, which are feathery appendages used for feeding
• Arthropod Ecology

  Crustaceans as food sources for other marine animals

  Copepods as the major diet for marine animals

  Symbiotic relationships (cleaner shrimp, barnacle commensalism with hosts)
• Phylum Chaetognatha (Arrowworms)

  Most common in tropical waters

  Inject toxin to incapacitate prey
• Phylum Echinodermata include sea stars, sea urchins, sea cucumbers
• Echinodermata have a water vascular system which are a network of canals, vales, and tube feel that play a role in locomotion, respiration, and sensory function
• Water Vascular System

  Madreporites: pore through which water enters the water vascular system

  Ampulla: internal water vascular system that supports tube feet
• Sea Stars part of the Asteroida class
• Sea stars have a central disk with five arms

  Carnivores and scavengers

  Can regenerate their arms

  Has the ability to extrude their stomach
• Brittle stars, basket stars, and serpent stars as part of the class Ophiuriodea
• Ophiuroidea have slender and flexible arms

  Noctournal

  Suspension/deposit/carnivore feeding
• Sea urchins and sand dollars as part of the class Echinoidea
• Sea urchins live on surfaces and scrape algae off of rocks
• Sand dollars bury in sand often in rows
• Anatomy of sea urchins include tube feed used for locomotion and food collection and Aristotle's Lantern (chewing structure for scraping food)
• Sea cucumbers as part of the class Holothuroidea
• Feather stars and sea lilies as part of the class Crinoidea

  Suspension feeders that filter small organisms from the water using tube feet and mucous nets
• Ecological roles of Echinoderms

  Sea otters eat sea urchins and sea stars

  Spider crabs feed on echinoderms
• Phylum Hemichordates (Acorn Worm)
• Phylum Chordata will have these characteristics at some point in their life:

  Notochord (slender skeletal rod)

  Dorsal, hollow nerve

  Pharyngeal gill slits

  Post-anal tail
• Class Ascidiacea (sea squirts) are filter feeders that remove plankton from the water
• Urochordata Class Thaliacea (salps)

  Pump water through their bodies to breathe

  Contain a pule jet for movement
• Urochordata Class Larvacea produce mucous structures to capture food
• Cephalochordata (sea lancelets) filter feed through gill slits
• Seven phylum dominate the marine environment: Mollusks, Arthropods, Chrodates, Sponges, Cnidarians, Annelids, Echinoderms
• Chordates include vertebrate fish
• Fish dominate vertebrates in the marine environment
• Three groups of marine fish

  Agnatha (jawless fish)

  Chondrichthyes (cartilaginous fish)

  Osteichthyes (bony fish)
• Most fish are bony fish
• Agnatha are eel-like with no paired appendages
• Agnatha include Hagfishes

  Able to regulate their oxygen by sending it to specific parts of the body

  Produce a protein that mixes with sea water and turns it into slime
• Agnatha: Lampreys

  Spend most of the time in the sea but go to freshwater to spawn (anadromous)

  Parasitic