Intro to Animal Diversity

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Intro to Animal Diversity
Chapter 32
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Animalia General Notes

• 1.3 million species
• 300K plant species
• 1.5 million fungi
• gt10 million bacteria
• Animals ARE heterotrophs
• Plantae? Fungi? Protista?
• Animals are multicellular
• Plantae? Fungi? Protista? Bacteria?

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Animalia General (Page 2)

• Unique in the possession of muscular and nervous
  tissue
• Lack cell walls
• Held together by structural proteins such as
  collagen
• Plants? Fungi? Bacteria? Protista?
• Most reproduce sexually
• Diploid stage is dominant in most

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Fertilization ? Zygote ? (Mitosis) Cleavage ?
Blastula
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Embryology Notes

• Cleavage rapid series of mitotic divisions w/o
  cell growth in between
• What part(s) of the cell cycle would be
  proportionally reduced during cleavage?
  Extended?
• Blastula Hollow ball of cells
• Cavity is called blastocoel
• Gastrula blastula gets punched in
• Embryonic tissue layers form from gastrulation
• Product of gastrulation called archenteron
• Blastophore is the opening of the archenteron

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2 Quick Things

• Some animals have a larval stage
• Immature, distinct form
• Undergoes metamorphosis to become adult form
• Hox genes
• Common in animals
• Genes that play an important role in development

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Animal Body Plans

• There are 3 main types of animal body plans
• No symmetry
• Sponges
• Radial symmetry
• Jellyfish and many primitive animals
• Central axis, and any cut through the axis
  results in mirror images

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Bilateral Symmetry

• Most amphibians, reptiles, birds, and mammals
• Produces a right and left sides that are mirror
  images of each other
• Usually produces dorsal and ventral sides
• Associated with cephalization
• Anterior (head) end
• Posterior (tail) end
• Concentration of sensory equipment at one end
• Usually anterior end

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• Coelomate
• True coelom
• Fluid-filled body cavity between digestive tract
  outer body wall
• True compartmentalization
• Pseudocoelomate
• Triploblastic animals
• -- 3 tissue layers
• Cavity formed from mesoderm endoderm
• Acoelomate
• ? No cavity between alimentary canal and outer
  body wall

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Germ Layers

• Give rise to the tissues and organs of the animal
  embryo
• Ectoderm is the germ layer covering the embryos
  surface
• Endoderm is the innermost germ layer and lines
  the developing digestive tube, called the
  archenteron

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Germ Layers

• Diploblastic animals have ectoderm and endoderm
• Triploblastic animals also have an intervening
  mesoderm layer these include all bilaterians
• A pseudocoelom is a body cavity derived from the
  mesoderm and endoderm

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Why a body cavity (coelom)?

• The separation between body wall and digestive
  tract have advantages
• Cushion suspended organs
• From blunt force and other sources of physical
  trauma
• Increased structural support
• Skeletal structure or hydrostatic skeleton
• Internal organs grow and move independently
• Greater specialization more advanced

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Coelom Formation

• In protostome development, the splitting of solid
  masses of mesoderm forms the coelom
• In deuterostome development, the mesoderm buds
  from the wall of the archenteron to form the
  coelom

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Fate of the Blastophore

• The blastopore forms during gastrulation and
  connects the archenteron to the exterior of the
  gastrula
• In protostome development, the blastopore becomes
  the mouth
• In deuterostome development, the blastopore
  becomes the anus

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