Lab 1

  1. symmetry
    similarity of form or arrangement on either side of a dividing line or plane
  2. how many types of symmetry?
    • four:
    • asymmetry, spherical, radial, bilateral
  3. Asymmetry
    • any line or plane through the center does not result in equivalent parts
    • ex: protists
  4. Spherical
    • al lines or planes passing through the center result in the same two equivalent parts
    • (many objects like basketablls and some protists [some algae[)
  5. Radial
    • any cut passing through the center results in two halves that are essentially idental; cuts usually through the medial axis which pass through the mouth of hte organism; the object or organism doesn't have radial symmetry as viewed from teh side
    • ex: cylinder, starfish, etcl
  6. bilateral
    • most common in animal kingdom
    • only one cut that can be made which will yield two essentially alike peices; vertical cut that passes through the center of the organism or object and extends the length of the organism or object
  7. Section/ plane
    surface passing through the body that divides it into two parts
  8. Bilaterally symmetrical organisms have which planes
    • median (midsagittal)
    • sagittal
    • parasagittal
    • frontal/ coronal
    • cross
  9. Median plane
    • vertical longitudinal plane passing through the organism
    • divides organism into two essentially identical halves, right and left
  10. sagittal
    any vertical longitudinal plane through the organism that is the median plane or any plane parallel to it
  11. parasagittal
    sagittal planes other than the median plane
  12. frontalĀ 
    any longitudinal plane which occurs at right angles to the sagittal plane
  13. cross
    any plane or section that is at right angles to both the sagittal and frontal planes
  14. radially symmetrical planes
    • radial
    • tangential
    • cross
  15. radial plane
    any plane or section that passes through teh center adn along the central axis; infinite number of cuts that can be made, all of which result in two identical portions
  16. tangential
    any plane or section that is parallel to the central axis but does not pass through the center
  17. cross
    a plane or section at right angles to the radial and tangential planes
  18. __ relates to the determination of the position of one point in relation to another
  19. Terms referring to the head end adn rear end fall into three major groups
    • superior and inferior (not four-legged animals)
    • cranial and caudal (all animals with brain case and tail, respectively)
    • anterior and posterior (part of body that goes forward or backward in locomotion)
  20. Terms referring to the back side and the belly side
    • Dorsal and Ventral
    • Anterior and Posterior
  21. Terms referring to points on or away from the midline or center
    • medial and lateral
    • central and peripheral (spheroidal part or organ)
    • superficial and deep
  22. Terms desribing appendages or partsz
    proximal and distal
Card Set
Lab 1
Planes and Symmetry