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Biol 11 Lesson 5 April 15 - Ch. 29 Echinodermata


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Biol 11 Lesson 5 April 15 - Ch. 29 Echinodermata

  1. 1. Homework from last class: <ul><li>Complete the Phylum Facebook project </li></ul><ul><li>Read Ch. 29-1 Echinodermata </li></ul>
  2. 2. Phylum Echinodermata: Echinoderms Chapter 29:Echinodermata pp. 637-644
  3. 3. BBC Life: Time Lapse of Sea Stars <ul><li> </li></ul>
  4. 4. <ul><li>Phylum Echinodermata </li></ul><ul><li>- echino = “spiny”, dermis = “skin” </li></ul><ul><li>Radial symmetry (often pentaradial) </li></ul><ul><ul><li>However, larvae have bilateral symmetry </li></ul></ul><ul><li>3 cell layers (ectoderm, endoderm, mesoderm) </li></ul><ul><li>Internal skeleton (endoskeleton) – plates of CaCO 3 </li></ul><ul><li>Water vascular system with tube feet </li></ul><ul><li>All marine </li></ul><ul><li>Very ancient group unlike those </li></ul><ul><li>of any other living group </li></ul>Introduction to Echinoderms
  5. 5. <ul><li>Echinoderms appear to be related to chordates (vertebrates). </li></ul><ul><li>Scientists think this because: </li></ul><ul><li>Echinoderm larvae are similar to certain chordate larvae. </li></ul><ul><li>Echinoderms have an endoskeleton (not exoskeleton). </li></ul><ul><li>Their pattern of embryonic development is same as for chordates ( radial cleavage – anus develops before mouth ) </li></ul><ul><ul><li>Mollusk, annelid, and arthropod embryos undergo spiral cleavage - mouth develops first. </li></ul></ul>
  6. 6. Classes of Echinoderms <ul><ul><li>1) Class Asteroidea: ex: star fish (aka sea stars) </li></ul></ul><ul><ul><li>Often pentaradial, usually predatory </li></ul></ul><ul><ul><li>Creep along using tube feet </li></ul></ul><ul><ul><li>2) Class Ophuroidea: ex: brittle stars </li></ul></ul><ul><ul><ul><li>Largest group </li></ul></ul></ul><ul><ul><ul><li>Often pentaradial </li></ul></ul></ul><ul><ul><ul><li>Filter feeders or detritus feeders </li></ul></ul></ul><ul><ul><ul><li>Flexible arms </li></ul></ul></ul><ul><ul><li>3) Class Echinoidea: ex: sea urchins, sand dollars </li></ul></ul><ul><ul><li>Some with protective spines </li></ul></ul><ul><ul><li>Usually grazers (eat algae) </li></ul></ul>
  7. 7. Classes of Echinoderms <ul><ul><li>4) Class Holothuroidea: ex: sea cucumbers </li></ul></ul><ul><ul><li>Usually detritus feeders (aka scavengers) </li></ul></ul><ul><ul><li>Radial symmetry </li></ul></ul><ul><ul><li>Often live in ‘herds’ on ocean floor </li></ul></ul><ul><ul><li>5) Class Crinoidea: ex: sea lilies and feather stars </li></ul></ul><ul><ul><li>Long, feathery arms </li></ul></ul><ul><ul><li>Sessile </li></ul></ul><ul><ul><li>Filter feeders </li></ul></ul><ul><ul><li>Rare today but lots of fossils of them </li></ul></ul>
  8. 8. Form and Function of Echinoderms <ul><ul><ul><li>Representative member: sea star </li></ul></ul></ul><ul><ul><ul><li>Digestive system: </li></ul></ul></ul><ul><ul><ul><li>Starfish pry open prey (ex: bivalves) with their tube feet, then flip stomach inside out into the prey and secrete enzymes to digest the tissue. Then they suck their stomach back in. </li></ul></ul></ul><ul><ul><ul><li> oral surface (location of mouth)  is on bottom </li></ul></ul></ul><ul><ul><ul><li> aboral surface (location of anus)  is on top </li></ul></ul></ul><ul><ul><ul><li>Scavengers (ex: sea cucumbers) </li></ul></ul></ul><ul><ul><ul><li>Filter feeders (ex. sea lillies) </li></ul></ul></ul>
  9. 9. <ul><ul><ul><li>Respiratory system: </li></ul></ul></ul><ul><ul><ul><li>Tube feet for O 2 /CO 2 exchange </li></ul></ul></ul><ul><ul><ul><li>Some species have “skin gills” </li></ul></ul></ul><ul><ul><ul><li>Circulatory and Excretory systems: </li></ul></ul></ul><ul><ul><ul><li>No separate systems for these (tube feet and skin gills are all over the body and take care of O 2 /CO 2 exchange and metabolic waste removal </li></ul></ul></ul><ul><ul><ul><ul><li>Nutrients (food) are distributed by digestive glands , not by blood (there is no blood ) </li></ul></ul></ul></ul>Sea star tube feet Adult sea star internal anatomy
  10. 10. <ul><ul><ul><li>Nervous system: </li></ul></ul></ul><ul><ul><ul><li>Primitive </li></ul></ul></ul><ul><ul><ul><li>No head </li></ul></ul></ul><ul><ul><ul><li>Nerve ring surrounds mouth; radial nerves in arms </li></ul></ul></ul><ul><ul><ul><li>Sea stars have eyespots at tip of each arm </li></ul></ul></ul><ul><ul><ul><li>Statocysts (to tell which side is up) </li></ul></ul></ul>
  11. 11. <ul><ul><ul><li>Musculoskeletal system: </li></ul></ul></ul><ul><ul><ul><li>Instead of muscles, sea stars have a unique water vascular system (hydraulics) </li></ul></ul></ul><ul><ul><ul><li>Water vascular system consists of: </li></ul></ul></ul><ul><ul><ul><li>ring canal: forms a circle around digestive system </li></ul></ul></ul><ul><ul><ul><li>radial canals: canals which extend into each arm </li></ul></ul></ul><ul><ul><ul><li>tube feet: suction-cuplike structures connected to the water vascular system </li></ul></ul></ul><ul><ul><ul><li>madreporite (sieve plate): opening used to filter water into the water vascular system </li></ul></ul></ul><ul><ul><ul><li>(see p. 639) </li></ul></ul></ul><ul><ul><ul><li>Sea star endoskeleton is composed of protective plates made of CaCO 3 (for protection , not involved in movement). </li></ul></ul></ul><ul><ul><ul><li>Some echinoderms can walk around on their arms (ex: brittle stars) or crawl (ex. sea cucumbers) </li></ul></ul></ul>
  12. 12. <ul><ul><ul><li>Reproductive system: </li></ul></ul></ul><ul><ul><ul><li>Usually separate sexes </li></ul></ul></ul><ul><ul><ul><li>“ Broadcast method” - sexual reproduction </li></ul></ul></ul><ul><ul><ul><li>Regeneration – asexual reproduction </li></ul></ul></ul><ul><ul><ul><ul><li>Many species can regrow lost parts </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Sea Star Renegeration </li></ul></ul></ul></ul><ul><ul><ul><ul><li> </li></ul></ul></ul></ul>
  13. 13. <ul><li>Sea stars control many populations (they are important predators) </li></ul><ul><li>Sea urchins often control algae populations </li></ul><ul><ul><li>Both sea stars and sea urchins have been known to upset the ecology of an area </li></ul></ul><ul><ul><li>Sea urchins are used in embryological research (large eggs) </li></ul></ul><ul><ul><li>Drug research (ex. anti-viral and anti-cancer drugs) </li></ul></ul><ul><ul><li>Some are edible delicacie s (ex. sea urchin eggs and sea cucumbers) </li></ul></ul>Ecology of Echinoderms
  14. 14. Demo – Sea Star Dissection
  15. 18. Homework for next class: <ul><li>Complete Echinoderms and Chordates Worksheet – </li></ul><ul><li>1 st side only (Section 29-1) </li></ul><ul><li>Complete sea star colouring diagram (include a key) </li></ul><ul><li>Work on 15 Ch. 29 Echinodermata cue cards </li></ul><ul><ul><li>Due Thursday, April 21 (Ch. 26-29 Invertebrate Test day) </li></ul></ul>Have a great weekend!
  16. 19. Works Cited <ul><li>Images taken from the following sources: </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul>
  17. 20. Works Cited <ul><li>Images taken from the following sources: </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul>