Comparative Anatomy

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Comparative Anatomy

• Studies in Vertebrate Structure

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• Introductory Concepts
• Evolution
• Kinds of Chordates
• Developmental Processes

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• What should we know about anatomy
• Parts
• Names
• Developmental Origins
• Functions

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• Introductory Concepts
• Evolution
• Kinds of Chordates
• Developmental Processes

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• Comparative - why comparative?
• Logical progression, learn in steps
• Comprehensive, know all vertebrates easily
• Broadens our frame of biological knowledge
• Phylogeny
• Evolution
• Embryology
• Physiological ecology

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• What is a chordate?
• In respect to other animals
• 3 germ layers (not a sponge)
• Bilateral symmetry (not a cnidarian)
• Tube gut (not a flatworm)
• Eucoelomate (not a round worm)
• Deuterostome (not mollusk, annelid, or arthropod)
• Segmented (not an echinoderm)
• Unique features of chordates
• Pharyngeal gill slits
• Notochord
• dorsal nerve chord

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• What are the chordate subphyla?
• Urochordata - tunicates
• Cephalochordata amphioxus
• Craniata (formerly vertebrata)
• Hagfish
• Lamprey
• Cartilagenous fish
• Bony fish
• Amphibians
• Reptiles
• Birds
• mammals

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• Phylogeny family tree of taxa
• Ontogeny - developmental process
• Von Baers Law
• features common to all members of major
  phylogenetic group of animals develop earlier in
  ontogeny than do features that distinguish
  subdivisions of the group
• (shared features develop earlier)

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• Conserved traits shared by all or most
  subgroups of a taxon and assumed to be passed
  down from one ancestral line
• Derived traits present within a subgroup of a
  taxon as a new trait which differentiates that
  subgroup from others.

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• The hierarchial system of taxonomy
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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• Problems with the hierarchial system
• Discrete levels oversimplify the phylogeny
• Arbitrary placement of taxonomic levels
• Backward jumps in taxonomic level names
• Standards for classification are not the same in
  all groups

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• Problems with the species concept
• Discerning the viability of hybrids
• Populations mix in some areas, but not others
• Ring species
• Checking for reproductive separation of
  allopatrics
• Clones and parthenogens
• Polyploid species

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• Lumpers and Splitters

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• EVOLUTION a controversial subject
• Diversity of viewpoints
• Literal Genesis, deny evolution
• Literal Genesis, accept natural selection
• Figurative Genesis, God directs evolution
• Figurative Genesis, God initiated universe
• Deny God as a factor in the natural world

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• Levels of scientific certainty
• Hypothesis --------------------------------gt
  Law
• Theory
• Law supported by all experimentation, and all
• alternatives disproven by
  experimentation

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• Five tiers of evolutionary concept
• Development of first life form
• Microevolution
• Natural Selection
• Speciation
• Macroevolution

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• Development of first life form
• Cooling of Earth allows molecule formation and
  development of an atmosphere with methane, water,
  ammonia, hydrogen, and nitrogen
• Further condensation forms organic molecules
• Accumulation of organic soup
• Organic macromolecules (preorganelles)
• First reproducing cell

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• Microevolution
• Replication and cell division errors result in
  genetic variants in a population
• Not all members of a population will have the
  same genomes

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• Natural Selection (survival of the fittest)
• Because not all members of a population have the
  same genetic make up, some may have a survival
  advantage.
• Evidences
• Peppered moth
• Pesticide resistance
• Galapagos finches

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• Speciation the isolation of a reproducing
  lineage from other lineages within the taxon
• The allopatric speciation concept
• Geographic separation
• Genetic change
• Reproductive isolation
• Sympatric speciation

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