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.

• 3x105 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 -- Plants

Subkingdom Tracheobionta -- Vascular plants

Superdivision Spermatophyta -- Seed plants

Division Magnoliophyta -- Flowering plants

Class Liliopsida -- Monocotyledons

Subclass Commelinidae

Order Juncales

Family Juncaceae -- Rush family

Genus Juncus L. -- rush P

Contains 117 Species and 167 accepted taxa overall

http://plants.usda.gov/

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 -- Plants

Subkingdom Tracheobionta -- Vascular plants

Superdivision Spermatophyta -- Seed plants

Division Magnoliophyta -- Flowering plants

Class Liliopsida -- Monocotyledons

Subclass Commelinidae

Order Juncales

Family Juncaceae -- Rush family

Genus Juncus L. -- rush P

Contains 117 Species and 167 accepted taxa overall

http://plants.usda.gov/

Juncus roemerianus ScheeleGroup - Monocot - Family - JUNCACEAE - Rush Family

Published in: Linnaea 22(3): 348. 1849. {Linnaea ; BPH 532.04}

Annotation: as "Roemerianus" Type - specimen(s) •T: Roemer s.n., USA: Texas: Mustang Island at Galveston (?). Next Higher Taxon:

Juncus L. Species Plantarum 1: 325-330. 1753.

http://mobot.mobot.org/W3T/Search/vast.html

History

• Greeks: – 4 elements (air, earth, fire, water). – Rational explanations for natural phenomena– Theophrastus (student of Plato & Aristotle) = “Father

of Botany”, 370-285 B.C.• Romans:

– Applied Botany – agriculture and pharmacy (herbal).– Pliny – Natural History, A.D. 23-79– Dioscoides – Materia Medica (drug plants), widely

used in Middle Ages• Islamic Scholars:

– Ibn Sina – Canon of Medicine, A.D. 980-1037

History• Renaissance:

– resurgence in natural history– Age of Herbals (1470-1670)– Driven by northern Europeans

• Need for taxonomy based on “natural” relationships, and system of naming.

• Carolus Linnaeus (von Linné) 1707-1778.– 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• 1930-40: 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 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 (1904-

2005) – “groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups” BUT see: http://en.wikipedia.org/wiki/Species

• Sexual vs Asexual reproduction• Alternation of Generations

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

Moniliformencrusting

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. 

Kidney beanBean reddish-brown4b.

Black beanBean black4a.

Pinto beanBean pigmentation mottled3b.

Go to 4Bean evenly pigmented3a.

Go to 3Bean has dark pigments2b.

White northernBean white2a.

Go to 2Bean elliptical or oblong1b.

Garbanzo beanBean round1a.

Kidney beanBean reddish-brown4b.

Black beanBean black4a.

Pinto beanBean pigmentation mottled3b.

Go to 4Bean evenly pigmented3a.

Go to 3Bean has dark pigments2b.

White northernBean white2a.

Go to 2Bean elliptical or oblong1b.

Garbanzo beanBean round1a.

Keys

• Electronic Keys – online, PDA downloadable.

• http://flora.huh.harvard.edu/china/ActKey/

• http://www.amnh.org/learn/biodiversity_counts/resources.html

• http://www.stingersplace.com/SLIKS/

Keys

• Electronic Keys – online, PDA downloadable.

• http://flora.huh.harvard.edu/china/ActKey/ http://www.amnh.org/learn/biodiversity_counts/resources.html

• http://www.stingersplace.com/SLIKS/

Keys

• Electronic Keys – online, PDA downloadable.

• http://flora.huh.harvard.edu/china/ActKey/ http://www.amnh.org/learn/biodiversity_counts/resources.html

• http://www.stingersplace.com/SLIKS/

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

http://herbarium.uvsc.edu/methods.shtml

http://www.mobot.org/mobot/imls/equipment.asp

Digital Herbariahttp://mobot.mobot.org/W3T/Search/vast.html

http://collections2.eeb.uconn.edu/collections/herbarium/database.html

Exercise

• Herbarium Sheets and “fresh” specimens

• Use keys to I.D. 3 species found in marsh habitats on the GCRL campus.

• http://ocean.st.usm.edu/~w546990/MarBot/index.html