{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

2.10.10 - Last major lineage to consider Deuterostomes...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Porifera Cnidaria Platy- Annelida Mollusca Nematoda Arthropoda Echino- Chordata helminthes dermata Lophotrochozoa Ecdysozoa Protistan ancestor Eumetazoa Bilateria Radiata Protostomia Parazoa levels of cell & tissue organization fundamental symmetry and number of germ layers Development patterns Cuticle presence or absence Deuterostomia Last major lineage to consider: Deuterostomes Like all protostomes, deuterstomes are triploblastic ; like many protostomes, they are eucoelomate . But they differ in the pattern of development: the anus ; mouth forms secondarily the mouth ; anus forms secondarily Blastopore forms: From gut, by enterocoely (archenteron outpocket ‘pinches off’ to form coelom) Schizocoely (blocks of mesoderm split internally to form coelom) Origin of coelom Endodermal , from archenteron ‘outpocket’ Ectodermal , from cells near blastopore Mesoderm formation Radial , indeterminate (cell fates established late in development) Spiral , determinate (cell fates established early in development) cleavage Deuterostomata Deuterostomata Protostomata The deuterostomes: Echinoderms & Chordates The deuterostomes: Echinoderms & Chordates Deuterostome development : formation of mesoderm and coelom Blastopore forms anus, mouth forms secondarily , hence, deuterostomes ( deutero = “second” , stome = “mouth” ) Mesoderm begins to form from outpockets of the early gut: enterocoely ( from endoderm) The deuterostomes: Echinoderms & Chordates Deuterostome development : formation of mesoderm and coelom Blastopore forms anus, mouth forms secondarily , hence, deuterostomes ( deutero = “second” , stome = “mouth” ) Mesoderm begins to form from outpockets of the early gut: enterocoely ( from endoderm)
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Mesoderm eventually completely lines the coelom (eucoelomate) anus mouth Ectoderm Mesoderm Coelom (from gut: Enterocoely) Endoderm Gut lumen The deuterostomes: Echinoderms & Chordates Deuterostome development : formation of mesoderm and coelom Porifera Cnidaria Platy- Annelida Mollusca Nematoda Arthropoda Echino- Chordata helminthes dermata Deuterostomia Lophotrochozoa Ecdysozoa Protistan ancestor Eumetazoa Bilateria Radiata Protostomia Parazoa The deuterostomes: Echinoderms levels of cell & tissue organization fundamental symmetry and number of germ layers Development patterns About 7,000 species, all marine substrate dwellers (larvae planktonic). Adults sedentary or slow-moving. Unique features (besides deuterostomate development) are: Pentaradial symmetry . After coelom formation, larva goes through a bilaterally symmetric stage which develops asymmetrically . Internal (dermal) skeleton (endoskeleton) made of ossicles of CaCO 3 . Movable in some species (spines). Internal water vascular system , derived from coelom. Used in locomotion and other functions. Connects to podia (short 'tentacles' or arms, often with grasping ends) -- also called tube feet .
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.
  • Winter '10
  • Chappel/Douhan
  • Phylum Chordata, Porifera Cnidaria Platy- Annelida Mollusca Nematoda Arthropoda Echino- Chordata helminthes dermata, Non-chordate invertebrate phyla

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern