METHODS AND TECHNIQUES FOR STUDYING MAMMALS

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CLASSIFICATION

classification from the University of Minnesota, General Zoology

 

Carolus Linnaeus (1707-1778) [Fig. 2.4]

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.  More from xrefer

    Biological Species Definition

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

ESTABLISHING RELATIONSHIPS

• Using the Evidence of Evolution: Classifying life.  A great overview from Kimball's Biology Pages

Taxonomic Keys

• Timme, S.L. 1991. How to Construct and Use a Dichotomous Key.  Pages 101-110, in Tested studies for laboratory teaching. Volume 12. (C. A. Goldman, Editor). Proceedings of the 12th Workshop/Conference of the Association for Biology Laboratory Education

Philosophies of Classification

1. numerical taxonomy
2. evolutionary taxonomy
   • dendrogram: phylogenetic tree
3. Phylogenetic Systematics (cladistics)
   • cladogram (Figs. 3.8, 3.18)
   • Journey into the world of phylogenetic systematics

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; 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

Determining Monophyly

• clade
1. monophyletic group
• homologous characters
1. character state inherited from common ancestor
• e.g. ostrich and robin wings
• bones in [analogous] bird, bat, & pterosaur wing
• 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
• 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 ecomorph.  Ecomorphs 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 [Figs. 3.18, 3.19]
• molecular clock

METHODS AND TECHNIQUES FOR STUDYING MAMMALS

FIELD METHODS

Trapping and Marking

Trapping

live trapping [Fig. 3.1]

kill trapping

Marking

tags

collars [Fig. 3.2]

dyes [Fig. 3.3]

clipping

Monitoring

radiotelemetry [Fig. 3.4]

home range [Fig. 3.5]

Geographic Information and Global Positioning Systems

Observational Methods

1. focal animal sampling [Fig. 3.6]
2. scan sampling:

Morphometrics

• study skins [Fig. 3.7]
• teeth and skeletons

taxonomic key

Physiological Measures

metabolic activity (Fig. 3.9)

LABORATORY METHODS - C

GENETICS AND MOLECULAR TECHNIQUES

Chromosomes

karyotypes [Fig. 3.11]

Protein Assays

protein electrophoresis [Fig. 3.12]

DNA assays

restriction fragment-length polymorphisms (RFLP’s)

nuclear DNA

mitochondrial DNA [Fig. 3.13]

DNA fingerprinting [Fig. 3.14]

variable numbers of tandem repeats

DNA sequencing

Table 3.1: usefulness of various genetic techniques for phylogeny

molecular clocks

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