Oct 6 - Animals Lecture #9

Phylum nematoda general characteristics most abundant

Info icon This preview shows pages 2–4. Sign up to view the full content.

Phylum Nematoda – general characteristics (most abundant in the planet) Chapter 12, Pages 222 - 234 Nemaode worms are ubiquitous! o Up to 4 million per square meter Good farmland topsoil estimated to contain billions/m2 “if all the matter in the universe except the nematodes were swept away, our world would still be dimly recognizable..” - N.A Cobb (1914) Nematodes exhibit considerable uniformity of both internal and external anatomy Long cylinder animals Typical nematode: o 1-2 mm long o Shows no external segmentation o Is tapered at both ends o Is cover by a multilayered cuticle Cuticle: o Non-cellular covering secreted by epidermis (may be lost in parasitic forms) o Provides structural resistance for high pressure hydrostatic skeleton
Image of page 2

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

Very pressurized on the inside (helps locomotions but can set up problems too) Locomotion o Internal hydrostatic pressure can be a high as 225 mm Hg (earthworm: 5-10 mm Hg) If you were to piece an earthworm, it won’t care If you pierce a nematode, it would be compromised and loses its internal pressure o Epidermis does not pocess any cilia o Nematodes possess longitudinal muscles but no circular muscles Moves like sinocodials waves (not very graceful) o Movement achieved by undulating waves, driven by alternating contractions of muscles o Muscle contraction controlled by nervous system o
Image of page 3
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.
  • Fall '08
  • General characteristics, Nematode, Rotifer, parasitic nematodes, mictic eggs, Parasitic intestinal nematodes

{[ 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