Micro+Macrotaxonomy

• Microtaxonomy


  The science of formally defining and naming species and their subcategories, and of assigning entities to species and their subcategories
• Microtaxonomy considers a very small scale and can be observed or identified
• Macrotaxonomy


  The classification of organisms above the species level
• Levels of taxonomy


  • Microtaxonomy
  • Macrotaxonomy
• John Ray, an English scholar, was the earliest systematists who achieved species definition in his major work "Historia Plantarum"


  1627–1705
• Ray's species definition


  Groups of plant that truly breed within their limits of variation
• Carolus Linnaeus, in his work Species Plantarum, described approximately 5900 species of plants known to man using mainly the floral structure and sexual characters


  1707–1778
• Linnaeus' species concept


  Simple, applicable and widely accepted
• De Candolle introduced the word taxonomy through his book Théorie Élémentaire de la Botanique and defined species as a collection of all the individuals which resemble each other more than they resemble anything else, which can by natural fecundation produce fertile individuals, and which reproduce themselves by generation


  1778–1841
• Charles Darwin considered species as the fundamental units of evolution, starting a new era of species definition


  1809–1882
• Darwin emphasized that species could be produced rapidly if the conditions were appropriate and in the absence of such conditions, species might remain unchanged for a long time
• In the 1920's, the science of genetics made powerful contributions in understanding the species evolution
• Modern species concepts


  • Biological Species Concept
  • Morphological Species Concept
  • Ecological Species Concept
  • Evolutionary Species Concept
  • Cohesion Species Concept
  • Phenetic Species Concept
  • Phylogenetic Species Concept
  • Pluralistic Species Concept
• Biological Species Concept (BSC)


  Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups
• Morphological Species Concept (MSC)


  The smallest groups that are constantly and determinedly distinctive and distinguishable by average means
• Ecological Species Concept (ESC)


  A lineage (or a closely related set of lineages) which occupies an adaptive zone minimally different from that of any other lineage in its range and which evolves separately from all lineages outside its range
• Evolutionary Species Concept (ESC)


  A single lineage of ancestor-descendant populations of organisms which maintains its identity from other such lineages [in space and time] and which has its own evolutionary tendencies and historical fate
• Cohesion Species Concept (CSC)


  An evolutionary lineage that serves as the arena of action of basic micro evolutionary forces, such as gene flow (when applicable), genetic drift and natural selection
• Phenetic Species Concept (PSC)


  A set of organisms that look similar to each other and distinct from other sets
• Phylogenetic Species Concept (PSC)


  A group of organisms that share an ancestor
• Pluralistic Species Concept (PSC)


  Recognizes that the factors that are most important for the cohesion of individuals as a species vary
• Species are the unit of evolution as they are the only things that reproduce and undergo modification
• Nominalistic Species Concept


  A name given for convenience, with only individuals existing and not universal classes
• Taxonomic categories


  Logical sets with definitions, but are arbitrary with multiple dichotomous keys possible
• Biological Species Concept


  Species are gene pools, a coadapted gene complex where conspecifics resemble each other because they are related
• Natural Populations


  An ecological unit where organisms derive their properties from the group, variation among individuals is important, and species must be understood with their environment
• hales + fish


  Swimming animals
• Linnaeus separated these
• lampreys + hagfish


  Jawless animals
• Agnatha


  Jawless animals
• Interbreeding


  A genetic unit, species are gene pools: a coadapted gene complex, conspecifics (members of the same species) resemble each other because they are related (have common ancestors)
• Natural Populations


  An ecological unit, organisms derive their properties from the group, variation among individuals is important, species must be understood with environment & other species
• Reproductively isolated


  A reproductive unit
• Reproductive Isolating Mechanisms (RIMs)


  • Features that prevent mating outside the species
• Species Recognition Mechanisms (SRMs)


  • Features that allow recognition of potential mates
• Lineage


  An ancestor-descendant series, genealogy is crucial: members of a species have a common ancestor, research program of paleontology is inference of genealogy, this can now be done by molecular methods
• Identity


  A biologically distinct entity, includes concepts associated with Biological Species, the BSC is the broadest general case of the ESC, Species Recognition Mechanisms (SRMS) permit recognition of conspecifics as mates
• Tendencies & Fate


  An historical entity, species have an origin (by cladogenesis = 'splitting' of lineages), undergo evolution (by anagenesis = change within lineages), & disappear (by extinction = termination of lineage)
• Allopatric speciation


  • Geographic separation, a population becomes separated, no more gene flow to other populations - poof, new biospecies on an operational level, over time, the new population evolves in its own direction, when is it different enough to consider a separate morphospecies?
• How new species become morphologically different from parent species

  • Natural selection, founder effect - NOT natural selection, genetic drift - NOT natural selection