Unit 5: The Evolutionary History of Diversity Extras  Study Guide

Chapter 32 An Introduction to Animal Diversity Review
  1. Animals are multicellular, eukaryotes that ingest their food.
  2. The ancestor of animals diverged from those of about 1.2 billion-800 million years ago, and may have resembled modern .
  3. The kingdom diversified about 525 million years ago, during the explosion, when many animal phyla appeared.
  4. Animals can be categorized by how their cells are organized according to a plan.
    • symmetry is like a flower pot, the body radiates from the center.
    • symmetry has a single plane of symmetry.
    • Most animals have that develop from embryonic layers of the .
    • Diploblastic animals such as jellyfish have germ layers: and .
    • Triploblastic animals have germ layers, including a .
    • The mesoderm may develop into tissue that line a fluid-filled space called a .
      • A is a body cavity only partially lined by mesoderm tissues.
      • Organisms without a body cavity are considered .
  5. The coelomates show two major modes of development.
    • Protostomes develop their from the blastopore of the gastrula.
    • Deuterostomes develop their from the blastopore.
  6. Current phylogeny places as a clade with true , and divides the Bilateria into three clades: , Lophotrochozoa, and Ecdysozoa.
    Review and exercise:
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