Chapter 32: An Introduction to Animal Diversity

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Chapter 32An Introduction toAnimal Diversity
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Animals

• Are multicellular, chemoheterotrophic, eaters of
  other orgranisms
• Consume by ingestion (mostly)
• Store energy using Glycogen
• Lack cell walls (as do protozoa)
• Employ collagen as structural protein
• Possess nervous and muscle tissue (mostly)
• Are diploid (mostly)
• Reproduce sexually (mostly)
• Employ motile sperm
• Develop from embryos (as do plants)

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Defining Embryo

• (botany) a minute rudimentary plant contained
  within a seed or an archegonium
• an animal organism in the early stages of growth
  and differentiation that in higher forms merge
  into fetal stages but in lower forms terminate in
  commencement of larval life
• An early stage in the post-fertilization
  development of an animal or plant egg
• An animal in the early stage of development
  before birth. In humans, the embryo stage is the
  first three months following conception
• Etc.
• From a Define Embryo google Search

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Animals Are

• Multicellular with differentiated cells
• Descendants of Choanoflagellate protists
• Parazoans vs. Eumetazoans
• Radiatans vs. Bilaterians
• Diploblastic vs. Triploblastic
• Protostomes vs. Deuterostomes
• Lophotrochozoa vs. Ecdysozoa vs. etc.
• Potentially possessors of body cavities
• Acoelomates vs.
• Pseudocoelomates vs.
• Coelomates vs
• None of the above

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Differentiating by Grade
Pseuo-coelomate
Acoelomate
Coelomates
Coelomates
Parazoa
Triplobastic
Diploblastic
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Colonial Choanoflagellate
Know at the level of being able to recognize the
morphology and name
Animal sister taxa or highly degenerate sponge?
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Development vs. Evolution
Note germ layers
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Colony to Animal Transition
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Invagination ? Surface Area
Sponges
Jellies
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Porifera Life Cycle
Is the sponge larvae the closest living thing to
the ancestral animal?
see Manuel Maldonado (2004). Choanoflagellates,
choanocytes, and animal multicellularity.
Invertebrate Biology 123(1)1-22.
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Radial vs. Bilaterial
Note that sponges are neither radial nor
bilaterially symmetrical
Cephalization having brain and senses at one end
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Acolomate
Note solid mesoderm
Platyhelminthes
Note that sponges and jellies cannot be described
as acoelomates, even though they dont have
coeloms
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Pseudocoelomate
Nematoda
Note that body cavity is not contained within
mesoderm
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Coelomate
Note body cavity is contained within mesoderm
A body cavity has many functions. Its fluid
cushions the suspended organs, helping to prevent
internal injury. In soft-bodied coelomates, such
as earthworms, the coelem contains
noncompressible fluid that acts like a skeleton
against which muscles can work. The cavity also
enables the internal organs to grow and move
independently of the outer body wall. p. 631,
Campbell Reece (2005)
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Protostome vs. Deuterostome
Sponges and jellies are neither protostomes nor
deuterostomes
Note that digestive tracts, even digestive
cavities, are not body cavities
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Differentiating by Grade
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Molecular Similarity
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The End