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Bio 11 Echinodermata Gap Notes

Biology 11

Name: ____________ __________________ Date: ________________ Block: _____________



Phylum Echinodermata (Greek: echinos = “spiny”, derma = “skin”)

Pages 340-341


I Background:


  • The Phylum Echinodermata includes 6 Subphyla that include a total of 18 Classes. Some of these Subphyla and Classes include:
    • Subphylum: _____________________________________ (Includes 4 Classes)
    • Subphylum: _____________________________________ (Includes 3 Classes)
      • *Class: ___________________________________- Sea Lilies and Feather-Stars*
      • Etc.
    • Subphylum: _____________________________________ (Includes 2 Classes)
      • *Class: ___________________________________ – Brittle Stars*
      • *Class: ____________________________________– Sea Stars *
      • Etc.
  • Subphylum: _____________________________________ (Includes 6 Classes)
      • *Class: ____________________________________ – Sea Urchins and Sand Dollars*
      • *Class: ____________________________________ – Sea Cucumbers*
      • Etc.
    • Subphylum: _____________________________________ (Includes 1 Class) (ALL EXTINCT!!!)
      • Etc.
  • Subphylum: _____________________________________ (Includes 2 Classes) (ALL EXTINCT!!!)


  • Echinoderms are completely _____________________ and only live on the bottom of the ocean floor


DID YOU KNOW!!!: The development of Echinoderms after the egg stage is so similar to that

of the Chordata, as well as being unique to only those two Phyla that it is believed that the Chordates (Vertebrates) and the Echinoderms share a common ancestor!!!


II Body Plan/Structure:


  • Echinoderms demonstrate a _____________________________ symmetrical body plan (Though it is strongly believed that they evolved from a bilaterally symmetrical ancestor, WEIRD!!!)
  • Most members of the Phyla are ____________________________ with _____________ similar body segments arrayed around a central core
  • They contain the three true germ layers:
    • ________________________________
    • ________________________________
    • ________________________________
  • All Echinoderms possess a true ______________________________________ made of _____________________________________________ that is covered with a layer of __________________________________
  • The Echinoderms possess a _________________________________________________
    • This is a system of fluid-filled _____________ that acts like a hydraulic pressure system
    • The system is used for ______________________________, _____________________ and ______________________________
    • Water is drawn into the water vascular system through a structure called a _______________________________.
    • The water travels down a structure called a _______________________________ until it reaches the circular ___________________________ that encircles the central core
    • The water is passed down to each _____________ through the _____________________________ where it enters the _____________________________ (Small bulbs)
    • The _______________________________ are connected to little sucker-like feet called ___________________
    • The ____________________ and the ______________________ are called ___________________________________


III. Feeding:


  • There are many forms of feeding among the Echinoderms from carnivores to filter feeders
  • Most echinoderms have a very ________________________ digestive system
  • There is a __________________ that is connected to a ______________________ that is connected to an ________________
  • The stomach extends into each arm where digestive juices are released to digest the food


DID YOU KNOW!!!: Sea Stars can be deadly carnivores. They will mount their prey

(usually an unsuspecting Bivalve) and wrap their arms around it until the opening of the Bivalve is facing the mouth of the Sea Star. From here the Sea Star pulls the Bivalve open using its sticky tube feet and powerful arms. It then everts its stomach into the Bivalve and digests the Bivalve inside its own protective shell. The Sea Star then pulls its stomach back inside to digest the organic material!!!


DID YOU KNOW!!!: Sea Urchins scrape food off of hard surfaces using a special structure

called Aristotle’s Lantern. Who knows, if you study hard and become a famous Philosopher and Biologist you could name an anatomical structure after yourself too!!!


  1. Respiration:


  • The thin-walled ________________ allow for simple _____________________ to occur
  • Some Echinoderms contain special __________ on their epidermis that aid in respiration
  • NOTE: There are always exceptions to the rules and there are some Echinoderms such as the Sea Cucumbers that have more advanced respiration systems


  1. Internal Transport:


  • The Water Vascular System is responsible for transporting ________________, _____________________and _____________________ throughout the body


  1. Excretion:


  • Undigested food is released out of the _______________
  • The Water Vascular System is again used to release metabolic wastes into the surroundings
  • The Wastes are released from the _________________



VII. Response:


  • Echinoderms have a central _________________ that surrounds the stomach
  • The central nerve ring connects to _____________________________ that extend into and control each arm
  • In general Echinoderms have a very ___________________ nervous system
  • They can generally only respond to:
    • ___________________________ – Use special structures found all over the body on the epidermis
    • ___________________ – Some have very very simple _______________ on the tips of their arms
  • The Echinoderms have some very interesting defence mechanisms
    • Sea Stars have ____________________________on their back side which act like pinchers and keep organisms off of them
    • Sea Cucumbers, when threatened will expel their ____________________________ in hopes of deterring their predator


VIII. Movement:


  • Echinoderms are either ____________________ or very slow moving
  • They use their Water Vascular System to pump water in and out of their _____________________ to crawl along the ground


DID YOU KNOW!!!: The ferocious Sunflower Star is by far the fastest moving Echinoderm

and can move at speeds up to 1 meter per minute!!!


  1. Reproduction:


  • The Echinoderms have separate _____________ and _________________ organisms
  • The _________________ of most Echinoderms take up the entire coelom
  • The __________ and _________________ produced by the gonads are simply released into the water by both sexes
  • Once the egg has been fertilized it matures into a _________________________ symmetrical larvae which eventually matures into the adult
  • Echinoderms also have the ability to ___________________________ body parts after they have been damaged or removed


  1. Ecological Roles:


  • Echinoderms are incredibly important in terms of ecological importance
  • Many of its members help recycle nutrients by feeding on decaying matter
  • Others help control the populations of the prey they feed on such as Bivalve population
  • They have also proven to be devastating to populations because if the Echinoderm populations are not themselves controlled they have a tendency to overeat and destroy





posted by Marc Bernard Carmichael in Biology Eleven,Biology Eleven Notes,Echinodermatat and have No Comments