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Coelom:

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Coelom: Fluid-filled body cavity lined by cells from the mesoderm In mammals it forms the peritoneal, pleural and pericardial cavities Acoelomate Pseudocoelomate ... – PowerPoint PPT presentation

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Title: Coelom:


1
  • Coelom
  • Fluid-filled body cavity lined by cells from the
    mesoderm
  • In mammals it forms the peritoneal, pleural and
    pericardial cavities

2
Acoelomate
Coelomate
Pseudocoelomate
3
(No Transcript)
4
Phylum Platyhelminthes Say What???Flat Worms
Planarians, Tapeworms, Flukes
5
Characteristics of Flatworms
  • Flatworms are the simplest of the worm groups
    20,000 species
  • SIMPLEST ANIMALS W/ ORGANS ganglia, eye spots,
    testes, ovaries, nephridiopores
  • They are found in many places and can be free
    living or parasitic.
  • A flatworm can be microscopic or many feet long
    and is generally very thin.

6
Characteristics of Flatworms
  • Show cephalization sensory organs in front of
    head to sense food, danger, mates
  • One of the best-known flatworms is the tapeworm.
    The tapeworm can get into a person's digestive
    tract and grow to enormous lengths.
  • Flatworms are found in marine and fresh water.

7
Body Cavity
  • Acoelomate lack an internal body cavity

8
Muscular-Skeletal System
  • A flatworm has no skeleton. It has tiny bristles
    called cilia that help it move as well as two
    layers of muscles under its skin. It has three
    cell layers called the endoderm, the mesoderm and
    the ectoderm.

9
Digestion
  • Mouth/Anus It takes food in and gets rid of
    wastes through the same opening (pharynx).
  • A flatworm has a gastrovascular cavity (highly
    branched) with one opening.
  • It eats small worms, insects and microscopic
    matter.

10
Digestion (cont.)
11
Nervous System
  • A flatworm has a very simple nervous system with
    two nerve cords running down either side.
  • It has two simple brains called ganglia, which
    are simple bundles of nerves.
  • It has two eyespots that help it sense light.

12
Nervous System (cont.)
13
Circulation
  • NONE!!

14
Respiration
  • Oxygen/carbon dioxide pass through worms body by
    diffusion

15
Reproduction
  • Sexually hermaphrodites simultaneous
    fertilization
  • Asexually A flatworm reproduces by splitting in
    two. When a flatworm is split up it immediately
    forms a new flatworm.
  • Flatworm Regeneration video

16
Excretion
  • A flatworm gets rid of wastes through the same
    opening it takes in food. Also, have flame cells
    (w/cilia) to get rid of excess water.

17
Symmetry
  • A flatworm has bilateral symmetry.

18
Other types of FlatwormsTapeworms
19
Other types of FlatwormsFlukes
20
Fluke life cycle
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