Comparative Anatomy - University of the Cumberlands

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Comparative Anatomy
Studies in Vertebrate Structure
• Introductory Concepts
• Evolution
• Kinds of Chordates
• Developmental Processes
• What should we know about anatomy
– Parts
– Names
– Developmental Origins
– Functions
• Introductory Concepts
• Evolution
• Kinds of Chordates
• Developmental Processes
• Comparative - why comparative?
– Logical progression, learn in steps
– Comprehensive, know all vertebrates easily
– Broadens our frame of biological knowledge
•Phylogeny
•Evolution
•Embryology
•Physiological ecology
• What is a chordate?
– In respect to other animals
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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
– What are the chordate subphyla?
• Urochordata - tunicates
• Cephalochordata – amphioxus
• Craniata (formerly vertebrata)
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Hagfish
Lamprey
Cartilagenous fish
Bony fish
Amphibians
Reptiles
Birds
mammals
• Phylogeny – “family tree” of taxa
• Ontogeny - developmental process
• Von Baer’s 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)
• 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.
• The hierarchial system of taxonomy
– Kingdom
– Phylum
– Class
– Order
– Family
– Genus
– Species
• 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
• 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
• Lumpers and Splitters
•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
• Levels of scientific certainty
Hypothesis --------------------------------> Law
Theory
Law – supported by all experimentation, and all
alternatives disproven by
experimentation
• Five tiers of evolutionary concept
– Development of first life form
– Microevolution
– Natural Selection
– Speciation
– Macroevolution
• 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
• Microevolution
– Replication and cell division errors result in
genetic variants in a population
– Not all members of a population will have the
same genomes
• 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
• 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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