Introduction to the Animal Kingdom

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Introduction to the Animal Kingdom Sponges

• Chapter 26

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Animal Kingdom Characteristics

• Basic functions feeding, respiring, circulating,
  excreting, responding, moving, and reproducing
• Heterotrophic cells
• No cell walls
• Multicellular
• Eukaryotic
• Asymmetry or symmetry
• Invertebrate or vertebrate

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Animal development

• Zygote fertilized egg (2n)
• Blastula hollow ball of cells that folds on
  itself at the blastopore opening
• Tube from blastopore is the digestive tract that
  can form the mouth (protostome) or the anus
  (deuterostome) from the opening.

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Embryonic tissues

• Endoderm inner layer ? digestive tract and
  respiratory system
• Mesoderm middle layer ? muscles, circulatory,
  reproductive and excretory organs
• Ectoderm outermost layer ? sense organs, nerves,
  and epidermis

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Body cavity

• Space where internal organs are housed
• coelomates, pseudocoelomates or acoelomates,
  depends how cavity is made

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Body symmetry
                                     
                                     

• Asymmetrical no plane dividing body into equal
  halves
• Radial symmetry multiple planes dividing body
  into equal halves
• Bilateral symmetry one plane dividing body into
  equal halves

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Body Symmetry
Section 26-1
Bilateral Symmetry
Radial Symmetry
Posterior end
Dorsal side
Anterior end
Ventral side
Plane ofsymmetry
Planes ofsymmetry
Figure 265 
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Cephalization
head

• Concentration of sense organs and nerves
• Usually associated with head region
• Defines the difference between head and tail
  regions

tail
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Introduction to Invertebrates
Click on image to play video.
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Invertebrates video 2
Click on image to play video.
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Sponges the simplest animals
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Sponge characteristics

• Invertebrate
• Multicellular
• Heterotrophic
• No cell walls
• Asymmetrical
• Few specialized cells

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The Anatomy of a Sponge
Section 26-2
Water flow
Osculum
Choanocyte
Central cavity
Pores
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
Figure 268 
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Choanocyte

• Collar cells that line cavity
• Obtains nutrients and oxygen from flowing water
  when flagella beat

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Spicule

• Spicule spike-shaped structure made by
  archaeocytes that move around in the sponge walls

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Archaeocytes

• processes food
• distributes nutrition to other cells

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Porocyte

• porous cells where water can flow into sponge
  cavity

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Boat that is harvesting sponges

• Spongin flexible protein found in soft sponges

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Feeding

• Filter feeders sift food from water current
• Intracellular digestion
• Choanocytes trap food that are then passed onto
  the archaeocytes.
• Waste flows out of the large opening.

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Respiration, Circulation, Excretion

• Rely on water movement through the body for gas
  exchange, nutrient and waste transport/elimination
  

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Response

• No nervous systems to respond to environmental
  changes
• Produce toxins that make them unpalatable or
  poisonous

To treat irritations from this sponge, apply a
vinegar-soaked cloth for 15 minutes. Use a piece
of adhesive tape on the wound to remove any
spicules.
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Reproduction

• Sexual
• Internal fertilization
• Sperm released, egg maintained
• Asexual
• Budding
• Gemmules groups of archaeocytes surrounded by
  spicules (much like spores)

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Sponge habitat photo by Justin Gilligan