SBI 3U

Identifying, Naming, and Classifying Species1Taxonomythe branch of biology that identifies, names, and classifies species (alive and extinct)

Callicebus caquetensis, a species of titi monkey, was discovered in the Colombian Amazon. (AP, 2010)2How do we identify and name a species?Species: a group of organisms that can interbreed in nature and produce fertile offspringThis is the most recognized defn of a speciesDoes this definition fit all organisms?

Callicebus caquetensis, a species of titi monkey, was discovered in the Colombian Amazon. (AP, 2010)Species ConceptsNo one defn fits everything, so we identify species based on three different species concepts (or definitions for a species)

Biological species concept Morphological species concept focuses on morphology compares body shape, size, and other structural featuresMorphology = branch of biology that deals with structure or form of organisms

Juvenile/Adult Koran Semicircule Angle fish (Pomacanthus semicirculatus)

Males can differ from females juvenile change appearance as they grow or age popn of same species can vary in different locations and exhibit striking differences4Species Concepts3. Phylogenetic species concept examines the phylogeny, or evolutionary history, of organisms

Phylogeny = the evolutionary history of a species- need to obtain genetic material from specimens and use DNA sequencing techniques- this is a powerful tool, but not always practical or possible to obtain a sample

Juvenile/Adult Koran Semicircule Angle fish (Pomacanthus semicirculatus)

Males can differ from females juvenile change appearance as they grow or age popn of same species can vary in different locations and exhibit striking differences5The father of taxonomyCarl Linnaeus (1707 1778) a Swedish naturalist and botanistDeveloped the first consistent classification systemEstablished a latin naming system which gave each species a unique two part name

6Binomial Nomenclature(two part naming system)The first name is the genus nameGenus = taxonomic level consisting of a group of closely related species Genus is Capitalized and in italicsThe second name is the species name (specific name)Species name identifies the particular speciesSpecies is lower case and in italicsE.g. Homo sapiens

7Binomial Nomenclature

Ursus americanusUrsus maritimusPhascolarctos cinereus8Classification in BiologyBiological classification = the systematic grouping of organisms into categories on the basis of defined criteriae.g. Grouping of organisms into trophic levels

9Linneaus Classification SystemBased on a hierarchical classification that has seven main levels or taxaKingdomPhylumClassOrderFamilyGenusSpecies

generalspecificTaxa = category used to classify organisms10Taxon (taxa plural) = a named group of organisms such as phylum Chordata or order Rodentia

Rank = a level in a classification scheme, such as phylum or order

11A Closer Look at the Kingdomsone of the disputes among taxonomists involve the number of Kingdoms

In this course we will use the six Kingdom system:BacteriaArchaebacteriaProtistaFungiPlantsAnimals

12Dichotomous Keysa series of branching either / or choices designed to classify specimens

13A sample Dichotomous Key

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