Phylum Echinodermata "Prickly Skin"

What is Phylum Echinodermata

• Salt Water / Benthic (Bottom of a Body of Water)

• Dermal Endoskeleton

  • Dermis 

  • CaCO3 ossicle / spines

Describe a Deuterostome

1. Blastopore (Opening of a central cavity of an embryo)

   1. Anus

2. Coelom (Fluid Filled Body Cavity)

   1. Enteroceolous (Forms coelom from pouches that are “pinched” off the digestive tract)

3. Cleavage 

   1. Radial (Equal)

   2. Indeterminate (Daughters not committed)

Describe a Protostome

1. Blastopore

   1. Mouth

2. Coelom

   1. Scizocoelous (Where the body cavity is formed by splitting off the mesoderm)

3. Cleavage

   1. Spiral (Not equal)

   2. Determinate (Daughters committed)

What kind of symmetry

• Pentaradial Symmetry (Can be divided into 5 equal parts)

  • Bilateral Symmetry for Larvae

What kind of vascular system

• Water Vascular System

  • Powers tube feet that have ampullae (muscular sac that pushes water into tube feet)

What does the pedicellariae do

Small pincer-like structures that are found on the surface and are used for Defense and Cleaning

What parts of the body does a starfish use for respiration

• Dermal branchiae (Also called skin gills, are little finger-like projections on the surface that aid in respiration and waste removal)

• Respiratory trees (A branching structure that is connected to the anus where water is drawn in and out in order to extract oxygen, are NOT in starfish)

• Bursae (sac-like cavities are used for both reproduction and respiration, NOT found in starfish but found in brittle stars)

• Gills

What is the type of reproductive strategy

• Dioecious (Externally)

  • Broadcast spawn (Have different seasons)

Describe Class Asteroidea (Starfish)

• Carnivore

• Pedicellariae (Defense and Cleaning pincer-like structures)

• Dermal Branchial (Also called skin gills, are little finger-like projections on the surface that aid in respiration and waste removal)

• Tube feet with ampullae

• Regeneration (Defense)

Describe Class Ophiuroidea (Brittle Stars)

• Carnivore

  • Serpentine arms (long snake-like)

    • Used for feeding and locomotion

    • Defense - Autotomize (detach arms)

• Deposit feeder (eats deposited organic matter on the seafloor)

• Tube feet - has NO ampullae

Describe Class Echinoidea (Urchins, Sand Dollars, Sea biscuits)

• Herbivore

• Aristotle’s Lantern (five toothed jaw)

• Teste (Name of internal skeleton)

  • Endoskeleton

• Spines

  • Defense and Locomotion

• Tube feet and Ampullae

• Gills

• Pedicellarial (Defense and Cleaning pincer-like structures)

Describe Class Holothuroidea (Sea Cucumbers)

• Tube feet with ampullae

• Suspension (Eats tiny food particles in water also known as filter feeder) / Deposit Feeder

  • Tentacle Crown (Ring of tentacles that are used to capture food like plankton and organic debris)

• Respiratory trees

• Defense

  • Tubules of cuvier (expelled through anus to entangle and immobilize predators when threatened, long white strands)

Describe Class Crinoidea (Sea Lilies and Feather stars)

• Suspension Feeders

• Tube feet, NO Ampullae

• Pinnules (feather-like appendages that branch off from main arms that forms the feathery appearance, serves as primary food collection)

Describe the Dissection Sheet for the Echinoderm (Starfish) Exterior

• Epidermis

  • Respiration through tiny finger-like structures (dermal branchiae)

  • Light, chemical, and water current detection

  • Contains small pincer like organs (pedicellariae) used for cleaning debris from the surface

• Dermal endoskeleton

  • Made of plates called ossicles that are made from calcium carbonate

  • Are held by connective tissue and provides the organism with both structural support and flexibility

• Peritoneum

  • A sheet of ciliated epithelial cells that lines the large internal body cavity (coelom)

  • Covers the internal organs

  • Circulates fluids 

  • Aids in Respiration

  • Removes waste (contains phagocytic cells (coelomocytes) that engulf waste materials, migrate to the tips of papulae and shed from the body, which contributes to excretion) 

• Mouth

• Arms

• Ambulacral grooves w/ tube feet

  • Narrow channels on the underside that have tube feet

  • Aids in locomotion, feeding, attachment, and protection (from ossicles and spines)

Describe the Dissection Sheet for the Echinoderm (Starfish) Interior (Central Disc)

• Madreporite

  • a sieve-like plate on a starfish's upper surface

  • Functions as the entry point for water into the vascular system

• Stone Canal

  • A duct within a starfish’s water vascular system

  • Transports water from the madreporite to the ring canal

  • Provides structural support

  • Powers locomotion and feeding

• Ring Canal

  • Circular canal that surrounds the mouth of the starfish

  • Central part of the water vascular system

  • Aids in water distribution, fluid regulation (connected to structures like polian vesicles, which may act as reservoirs to store water and help regulate fluid pressure within the system.), and defense (Gives rise to Tiedemann's bodies, which are thought to produce defensive cells called amoebocytes)

• Radial Canal

  • Tube that extends from the ring canal to the tip of each arm in the water vascular system

  • Transport water from the ring canal to the ampullae

  • Helps extend, retract, and move its tube feet for locomotion and feeding

• Lateral Canal

  • Small short canal that connects the radial canal to an ampullae

  • Are apart of the water vascular system and aids in locomotion and feeding

  • Help control the water that goes in and out of the tube feet

• Ampullae

  • Small bulb like structures that acts as a hydraulic pump for movement

  • Extends and retracts tube feet and powers movement

  • Aids in feeding

• Tube feet

  • Suction-cup-tipped appendages on the underside of a starfish

  • Used for movement, feeding, respiration, and attachment

• Cardiac Stomach

  • One of the two stomachs of a starfish

  • Can be pushed out to externally digest prey

  • Secretes digestive enzymes to liquify prey and then consumes the prey and then retract the stomach to complete digestion

• Pyloric Stomach

  • Upper stomach that continues the digestion after the cardiac stomach

  • Connects to the pyloric caeca

• Pyloric Ceca

  • Also known as Pyloric Caeca

  • Are two digestive glands that are found in each arm

  • absorb, store, and transfer through the body nutrients from food they eat

• Gonads

  • Reproductive organ that produces gametes (sperm and eggs) and hormones

  • Pair of gonads are located in each arm of the starfish that release eggs or sperm to fertilize externally

• Ambulacral Ridge

  • Raised structure along the middle of a starfish’s arm and contains the ambulacral groove and tube feet

  • Acts as protective ridge for groove and tube feet and provides skeletal support for the starfish’s locomotion

• Ambulacral Groove

  • A channel on the underside of a starfish that contains and protects tube feet

  • Aids in locomotion and feeding due to housing tube feet

  • Usually protected by spines are are double rowed and can be moved to close over it