Animal Kingdom by yurtgc548

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									Animal Kingdom
          Two Types

1)Invertebrates- do not have a
  backbone



2) Vertebrates- have a
   backbone
          Cell specialization

Every animal starts out as a blastula- a ball
  of cells.
The ball folds in on itself and forms a single
  opening called a blastopore.
The blastopore leads into a central tube that
  runs the length of the embryo.
This tube will become the digestive tract.
   Two types of central tubes

1) Protosome- is an animal whose
   mouth is formed from the
   blastospore.
2) Deuterosome- is an animal
   whose anus is formed from the
   blastospore.
         Embryo development
The cells that form from the blastula form three
   distinct layers.
A) Endoderm- the intermost germ layer, these
   cells become the digestive tract and the
   respiratory system
B) Mesoderm-the middle layer, becomes the
   muscles, the circulatory, reproductive and
   excretory system
C) Ectoderm-the outmost layer, becomes the
   sense organs, nerves and out layer of skin
            Phylum Porifera

• Sponges are the simpliest animals
• The word “Porifera” means pore-bearers
• Water flows into and out of tiny pores (go
  in ostia and go out oscula) all over their
  bodies.
• Food comes in with the water (dissolved
  nutrients)
Why are Sponges animals?

Sponges are classified as anumals
 because they are multicellular,
 heterotrophic, have no cell walls
 and contain a few specialized cells
Characteristics of Sponges

1) Multicellular
2) Body with pores that serve as a passage
   for water.
3) Mostly marine, all aquatic (habitat)
4) Mostly epidermal cells with Choanocytes
   on the inside. These are cells with
   flagellum that create water currents
        Characteristic (cont.)
5) Simple skeletal structure made of spiny
  spicules (spike shaped structure made of
  chalk-like calcium carbonate or glass-like
  silica) Spicules are made by archaeocytes;
  specialized cells that move around within
  the walls of the sponge.
6) No true organs or true tissues
7) Digestion happens intercellularly
Characteristics (cont)

8) Excretion and respiration by diffusion
9) Most likely no nervous system—no
  response to stimuli
10) Asexual reproduction by buds and
  sexual reproduction by eggs and sperm;
  free swimming ciliated larvae
Habitat and protection
Sponges are important in aquatic type
  environments.
They are sessile, which means that they
  stay put. Their structures are varied so
  they can become homes for other
  organisms.
They commonly practice mutalism, a
  situation in which both partners benefit
Some sponges provide protection to small
  organisms while others contain
  photosynthetic organism that need
  sunlight to thrive.
Some spicules have a cross-shaped
  antennae which directs sunlight to the
  photosynthetic parts like a magnifying
  glass or lens.
               Predators

Sponges thrive because they have few
  predators.
They also have a noxious odor which makes
  sampling them unpleasant.
Because of their skeleton in would be like
  eating splinters of glass.
        Classes of Sponges
Calcarea- calcium carbonate spicules
Hexactinellida- six-rayed silica containing
  spicules
Demospongiae- skeleton made of silica or
  spongin (specialized collagen)
Sclerospongiae- contain massive amounts of
  calcareous (calcium carbonate) skeleton
  with silica spicules.

								
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