INTRODUCTION TO MAMMALS

DOWNLOAD an Adobe Acrobat version of the lecture outline 3 slides or 6 slides per page

Mammalian Diversity

  1. 5,400 mammal species (Wilson and Reeder, 2005, Mammal Species of the World).
  2. In 1993, 4,700 species were recognized.
  3. Compare this to 20,000 fish species or 750,000 described insect species.

 

CLASSIFICATION

classification from Science at a distance by Professor John Blamire
 
Carolus Linnaeus (1707-1778)
taxonomy
          Linnaean System
    hierarchal system: hierarchy of taxonomic ranks.
        Domain
            Kingdom
                Phylum
                    Class
                        Order
                            Family
                                Genus
                                    Species
Group name endings 
        Superfamily -oidea (e.g., Canoidea)
        Family -idae (e.g., Canidae)
        Subfamily -inae (e.g., Caninae)
 
Binomial nomenclature
  • Species of animals are assigned unique scientific names.  A species name always consists of two parts:  the Genus and specific epithet.   The genus name is always first and capitalized.  The specific epithet is second and not capitalized.   Following Linnaeus, who used Latin for species names, the genus and/or species name is italicized or underlined. 

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    Carl von Linné, portrait by Alexander Roslin, 1775. Currently owned by and displayed at the Royal Swedish Academy of Sciences.

    This is a file from the Wikimedia Commons.

     

     

     

       

    What is a species?

    1. Introduction from UC Berkeley

    Biological Species Definition

    1. "Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups." Mayr 1942 
    2. "All members of the same species share a common gene pool." Dobzhansky 1950

    Phylogenetic species concept: from UC Berkeley

    1. a species is a "tip" on a phylogeny, that is, the smallest set of organisms that share an ancestor and can be distinguished from other such sets.

    ESTABLISHING RELATIONSHIPS

    Taxonomic Keys

    Philosophies of Classification

     

    Terminology  
    character:
    recognizable attribute
    apomorphy:
    derived or specialized character
    plesiomorphy
    primitive or ancestral character
    autapomorphy
    characterizes a terminal branch only
    synapomorphy
    shared derived character inferred to have originated in the latest common ancestor
    sister groups:
    two monophyletic groups share a common ancestry with each other more recently than either one does with any other taxa
    monophyletic:
    entire phylogeny; latest common ancestor plus all and only all its descendants
    paraphyletic:
    group having a common ancestor; but from which one or more descendent groups have been excluded; can not be defined strictly by synapomorphies; part of phylogeny; e.g. Class Reptilia if it does not include birds; stem groups
    polyphyletic:
    descendents of unrelated ancestors; does not include the common ancestor of at least two taxa; taxa are grouped together because of convergent evolution

     

    paraphyly
    The traditional class Reptilia (green field) is a paraphyletic group comprising all amniotes other than the mammals and birds.
    From Wikipedia

    phylogeny
    Cladogram of the primates, showing a monophyletic group (the simians, in yellow), a paraphyletic group (the prosimians, in blue, including the red patch), and a polyphyletic group (the night-active primates, the lorises and the tarsiers, in red) From Wikipedia

    Determining Monophyly
     
    • clade
      1. monophyletic group
    • homologous characters
      1. character state inherited from common ancestor
        • e.g. ostrich and robin wings
        • bones in bird, bat, & pterosaur wing. [The wings themselves are analagous]
        • bones in any tetrapod limb
      2. homology is determined by position relative to other structures; development (embryological tissue, pattern of ontogeny) & evolution
      3. UCMP on homology and analogy
    • analogous
      1. similar function
      2. arose independently
        1. wings of birds and bats, although the bones in the wings are homologous
    http://commons.wikimedia.org/wiki/File:Homology_vertebrates.svg
    • convergent evolution:
      1. similar features from different ancestors as a result of ecological equivalence
      2.   convergence in placental and marsupial mammals- Dr. George Johnson's Backgrounder
      3. Another term used to describe convergence is ecomorphEcomorphs are distantly related taxa with similar morphologies that occupy similar niches.   Ecomorphs typically are similar in both dietary preferences, feeding adaptations, and locomotor adapatations.
        1. DOWNLOAD  this Word Document or Adobe Acrobat document containing a list of Mammalian Locomotor and Feeding Categories that you are expected to know.
    • parallel evolution:
      1. independent modifications from the same ancestor
        •    elongate body of salamanders by independent evolution of extra vertebrae;
        •    possibly some genera of burrowing rodents.
    • homoplasy
      1. character similarity that misrepresents common descent as a result of convergence, parallelism, or reversal
    • molecular phylogeny

     

    http://www.bio.miami.edu/dana/pix/placental_marsupial.jpg

       

     


    METHODS AND TECHNIQUES FOR STUDYING MAMMALS


    FIELD METHODS

    Trapping and Marking

    Trapping
    live trapping
    kill trapping
    Marking
    tags
    collars
    dyes
    clipping
    Monitoring
    radiotelemetry
    home range [Table 23-1]

    Geographic Information and Global Positioning Systems


    LABORATORY METHODS - A

    Morphometrics

    LABORATORY METHODS - B

    GENETICS AND MOLECULAR TECHNIQUES

    Chromosomes
    karyotypes
    Protein Assays
    protein electrophoresis
    DNA assays
    restriction fragment-length polymorphisms (RFLP’s)
    nuclear DNA
    mitochondrial DNA
    DNA fingerprinting
    variable numbers of tandem repeats
    DNA sequencing

     -

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