Taxonomy & Classification Lecture 2

Overview What is taxonomy? History of Classification What is a species? Reproductive strategies in plants Specialized Terminology Dichotomous Keys Electronic Keys Herbarium Specimens/Collecting

Taxonomy Defn: classification of things (plants, animals). Requires NAMES. 3x10 5 sp of plants Kingdom, Division, Class, Order, Family, Genus, Species, Subsp, Var. (Authority) Binomial Nomenclature (Systema Naturae) – Carolus Linnaeus

Classification for Kingdom Plantae Down to Genus Juncus L. Click on names to expand them, and on P for PLANTS profiles. Up to the Kingdom Kingdom Plantae -- PlantsPlantae Subkingdom Tracheobionta -- Vascular plantsTracheobionta Superdivision Spermatophyta -- Seed plantsSpermatophyta Division Magnoliophyta -- Flowering plantsMagnoliophyta Class Liliopsida -- MonocotyledonsLiliopsida Subclass CommelinidaeCommelinidae Order JuncalesJuncales Family Juncaceae -- Rush familyJuncaceae Genus Juncus L. -- rush PJuncus L. P Contains 117 Species and 167 accepted taxa overall

Classification for Kingdom Plantae Down to Genus Juncus L. Click on names to expand them, and on P for PLANTS profiles. Up to the Kingdom Kingdom Plantae -- PlantsPlantae Subkingdom Tracheobionta -- Vascular plantsTracheobionta Superdivision Spermatophyta -- Seed plantsSpermatophyta Division Magnoliophyta -- Flowering plantsMagnoliophyta Class Liliopsida -- MonocotyledonsLiliopsida Subclass CommelinidaeCommelinidae Order JuncalesJuncales Family Juncaceae -- Rush familyJuncaceae Genus Juncus L. -- rush PJuncus L. P Contains 117 Species and 167 accepted taxa overall Juncus roemerianus Scheele Group - Monocot - Family - JUNCACEAE - Rush Family Published in: Linnaea 22(3): {Linnaea ; BPH } Annotation: as "Roemerianus" Type - specimen(s) T: Roemer s.n., USA: Texas: Mustang Island at Galveston (?). Next Higher Taxon: Juncus L. Species Plantarum 1:

History Greeks: –4 elements (air, earth, fire, water). –Rational explanations for natural phenomena –Theophrastus (student of Plato & Aristotle) = “Father of Botany”, B.C. Romans: –Applied Botany – agriculture and pharmacy (herbal). –Pliny – Natural History, A.D –Dioscoides – Materia Medica (drug plants), widely used in Middle Ages Islamic Scholars: –Ibn Sina – Canon of Medicine, A.D

History Renaissance: –resurgence in natural history –Age of Herbals ( ) –Driven by northern Europeans Need for taxonomy based on “natural” relationships, and system of naming. Carolus Linnaeus (von Linné) – Species Plantarum 1753 –based on doctrine of “the constancy of species”

History 1859: Origin of Species (Darwin & Wallace) 1866: Laws of Inheritance (Mendel) 1866: “Phylogeny” (Haeckel): genealogical relationships through evolution : Neo-Darwinism (Morgan, Fisher, Haldane, Huxley, Mayr, etc.) –combination of theory of the evolution of species by natural selection, and theory of genetics as the basis for biological inheritance and mathematical population geneticsevolutionspeciesnatural selectiongeneticspopulation genetics –Mechanism still lacking 1959: DNA molecule (Watson & Crick) Recent: Mechanisms of Replication and Transcription, mutations, inheritance, speciation, biotechnology, gene manipulation, cloning, etc.

Species “Fundamental unit” of Taxonomy Reproductively compatible: Mayr ( ) – “groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups” BUT see: Sexual vs Asexual reproduction Alternation of Generations

Phytoplankton

Macroalgae - Chlorophyta

Macroalgae - Phaeophyta

Macroalgae - Rhodophyta Porphyra sp. = Haploid Gametophyte vs. Conchocelis sp. = Diploid “sporophyte”

Vascular Plants

Life - Histories Cyano & Phytoplankton: –Asexual (N) vs cysts (2N) Macroalgae: alternation of generations –Gametophyte (N) & gametes (Motile) vs. Sporophyte (2N) and spores, Vascular Plants: Sporophyte (2N) –Flowers are specialized “gametophyte”

Terminology Cyst, frustule, Thallus, root, rhizome, shoot, stem, leaf, flower Branching patterns: dichotomous, alternate, radial/whorled, etc “Stem”: terete, moniliform, cylindrical, etc Leaf: shapes… Flower: petals, color, stamen, pistil, etc

Dichotomous Moniliform encrusting

THALLUS SHEET COARSLEY - BRANCHED JOINTED - CALCAREOUS THICK - LEATHERY FILAMENT ENCRUSTING

Keys Dichotomous – 2 choices: –A dichotomous key is an organized set of couplets of mutually exclusive characteristics of biological organisms. –The couplets can be presented using numbers (numeric) or using letters (alphabetical). –The couplets can be presented together or grouped by relationships. –There is no apparent uniformity in presentation for dichotomous keys.

Sample keys to some common beans used in the kitchen Numeric key with couplets presented together. The major advantage of this method of presentation is that both characteristics in a couple can be evaluated and compared very easily. Alphabetical key with couplets grouped by relationship. This key uses the same couplet choices as the key above. The choices within the first and succeeding couplets are separated to preserve the relationships between the characteristics.

Keys Electronic Keys – online, PDA downloadable. unts/resources.htmlhttp:// unts/resources.html

Keys Electronic Keys – online, PDA downloadable. unts/resources.htmlhttp://flora.huh.harvard.edu/china/ActKey/ unts/resources.html

Keys Electronic Keys – online, PDA downloadable. unts/resources.htmlhttp://flora.huh.harvard.edu/china/ActKey/ unts/resources.html

Collecting Actual plant parts – reproductive structures, leaf. Dried, pressed, glued Label: Genus, Sp, Date, location, who Collection = Herbarium Observational records – confidence? Digital Herbaria and Observations D-GPS, Dig Camera, PDA

Digital Herbaria database.html

Exercise Herbarium Sheets and “fresh” specimens Use keys to I.D. 3 species found in marsh habitats on the GCRL campus. /index.html