Chapter 32-34: Animal Diversity

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• Chapter 32-34 Animal Diversity
• Objectives
• Define common characteristics amongst all animals
• Animals can be characterized by body plans
• Molecular data is providing new data for
  phylogeny
• Understand life without a backbone
• Understand life with a backbone

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What does it mean to be an animal? -Animals get
food by 1. Ingesting - Differs from absorption
(Fungus) 2. Rely on other organism for food or
are heterotrophic unlike plants -Animals are
multicellular unlike protists 1. Specialized
cells (nervous and muscular are not found in any
other multicellular organism 2. Cells are held
together by proteins (mostly collagen which is
only found in animals) -Reproduction is mostly
sexual with the 2n version dominating
life -Development into layers - leads to organs
and tissue
-Some development includes a larval stage
-sexually immature stage and undergoes
metamorphosis -Use of Homeoboxes or gene
regulatory genes are common to all animals - many
have similar DNA sequences
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• Body Plan Set of morphological and developmental
  traits that work together as a whole.
• Research suggests gastrulation has remained
  unchanged for 500 million years but other aspects
  of body plans have changed.
• Symmetty Tissue
• Asymmetry Sponges Specialized cells isolated
  from other tissues by membranes (Called Germ
  layers during
• Radial Symmetry development)
• Bilateral Symmetry
• -Dorsal
• -Ventral
• -Anterior
• -Posterior
• -Cephalization

• 1. Ectoderm Surface of embryo becomes outer
  
• covering and nervous system
• Endoderm Inner surface becomes inner wall of
  organs and digestive tract.
• Mesoderm middle layer becomes other organs
  and muscles between the digestive tract and outer
  layer
• -Organisms that only have endo and ecto are
  considered diploplasts
• -Organisms that have all three are considered
  triploblasts
• All bilaterally symmetrical

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Body Cavities of Triploblasts -Coeloms prevent
injury to organs -Allow organs to move and
grow indpendently of outer shell -Humans are
?????
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Determinate Cleavage means cells are
differentiated very early. Ex. Take one cell out
and the organism will develop missing many parts
and inviable
Cells retain ability to turn into any type of
cell Ex. Identical Twins in humans
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• Points of agreement of the two
• Kingdom is Monophyletic and all animals share a
  common ancestor
• Sponges branch from the base of both
• Clade opposite of Sponges (Eumetazoa) includes
  organisms with true tissue
• Most animals are in the Bilateria clade
• Chordates are Deuterostomes

Morphological and Developmental Phylogenetic Tree
Molecular Data Phylogenetic Tree
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• Invertebrates No Backbone
• Sponges lack true tissue (Basal or outgroup)
• Eumetazoans contain true tissues (derived
  Characteristics)
• Bilateria contains organisms with bilateral
  symmetry, triploblastic development, most are
  coelomates and contain three major clades
• Lophotrochozoa
• Ecdysozoa
• Deuterostomia
• (Deuterostome development and
• includes chordates and
• vertebrates)

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Sponges p. 670 -Thought to have been plants
-Suspension Feeders -Water is drawn through
pores and a current provided by the
flagella -Ameobocytes take food particles to the
rest of the cells
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Cnidarians (Jellyfish, Coral) -Simple diploblast
radial body plan -Polyp adheres to
something -Medusa free moving form -Carnivores
-No brain but responds to stimuli from all
directions
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Lophotrochozoans -Clade includes 18 phyla -Most
diverse animal clade (very different body
plans) -Clade is molecularly monophyletic
Phylums include -Tapeworms -Mulluscs (snails,
slugs, mussels, clams, oysters, squids and
octopuses) -Annelids (earth worms and leeches)
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Ecdysozoa a group defined by shedding of a tough
external coat or molting. -The Arthropods most
species rich animal group
Complete vs Incomplete metamorphosis

• Common Characteristics of Arthropods
• Exoskeleton and Molts
• Well developed senses
• Open circulatory system
• Four major lineages
• -Spiders, ticks, mites
• -Millipedes and Centipedes
• -Insects
• -Crabs, lobsters, and shrimp

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Deuterostomia includes both Echinoderms and
Chordates -Based mostly on Molecular data
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• Derived Characteristics of Chordates
• Notochord - Present in all embryos and turns into
  backbone/vertebrae
• Presence of a hollow dorsal nerve chord that
  turns into the nervous system
• Presence of Pharyngeal slits
• Presence of post anal tail

p. 734 for other derived characteristics