Plant Names and Classification
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Transcript of Plant Names and Classification
Plant Names and Classification
Chapter 16
Outline Introduction Development of the Binomial System of
Nomenclature• Linnaeus• The International Code of Nomenclature for Algae,
Fungi, and Plants Development of the Kingdom Concept Classification of Major Groups The Species Concept
Introduction All living organisms given two-word Latin scientific name
= species name• Only one correct scientific name for species• Many common names may be given to same species
− Dicentra cucullaria - Dutchman’s breeches, little-boy’s breeches, monkshood, boys-and-girls, soldier’s cap, white hearts,…, plus others in different languages
• Or one common name applied to number of different species
− Monkshood for Dicentra cucullaria and Aconitum species
Development of the Binomial System of Nomenclature
1st attempt to organize/classify plants - Theophrastus (4th century B.C.)• Classified nearly 500 plants by leaf characteristics
13th century - distinction made between monocots and dicots
Beginning of 18th century - details of fruit and flower structure, in addition to form and habit, used in classification schemes• Latin phrase name given to plants and animals
− First word of phrase indicated genus (plural: genera)
Development of the Binomial System of Nomenclature
• Published Species Plantarum, 1753
• Changed Latin phrases to reflect relationships and placed one to many species in each genus
− Abbreviated names to 2 parts (binomials)
Carolus Linnaeus (1707–1778) - established Binomial System of Nomenclature
Development of the Binomial System of Nomenclature
Binomial System of Nomenclature• All species named
according to this system, includes authority for species name
− Spearmint: Mentha spicata L.
A page from
Species Plantarum
by Linnaeus
The International Code of Nomenclature for algae, fungi, and plants
Book standardizes rules governing naming and classification of plants• Linnaeus starting point for names• Rules revised and expanded at periodic international
botanical congresses• Has English, French and German translations• Requires 2 steps to officially recognize new plant
species:− English or Latin description or diagnosis must be
published in journal or other public publication− Author must designate type specimen deposited in
herbarium
Development of the Kingdom Concept When classification schemes first developed,
organisms placed in either Plant Kingdom or Animal Kingdom• Distinction works well for complex animals, but not
for simpler organisms
Hogg and Haeckel proposed 3rd kingdom in 1860’s• All organisms that did not develop complex tissues
placed in Kingdom Protoctista
Development of the Kingdom Concept In 1938, Copeland assigned single-celled, prokaryotic
organisms to Kingdom Monera, leaving algae, fungi and single-celled eukaryotic organisms in Protoctista
In 1969, Whittaker developed 5-kingdom system• Split Fungi from Kingdom Protista
In 1980s, Woese argued Monera should be split into Archaea and Bacteria, resulting in 6 kingdoms• Archaea, Bacteria, Protista, Fungi, Plantae, Animalia
Classification of Major Groups
3 domains: Bacteria, Archaea, Eukarya
Depending on classification system, between 12-30 plant phyla recognized
In-between categories, such as subphylum, subclass, suborders subspecies, varieties and forms also used
Classification of Major Groups 1st part of species name = genus 2nd part of species name = specific epithet• Specific epithet followed by author(s) who named the
plant Taxonomists specialize in identifying, naming, and
classifying organisms Systematists incorporate evolutionary processes to sort
out natural relationships Dichotomous keys help identify organisms• Choose features from paired statements that most
closely apply to organism
The Species Concept Morphological species concept - species
defined by morphology
Interbreeding species concept - species a population capable of interbreeding and reproductively isolated from other groups
Ecological species concept - species a group of related individuals that occupy unique ecological niche
The Species Concept Cladistic species concept - species determined by
phylogenetic history• Individuals with common evolutionary background =
species− Cladistic methods used to determine evolutionary
historyExamines natural relationships among organisms,
based on shared featuresRelationships portrayed on cladogramsValue or form of feature referred to as character
stateHypotheses made about which state ancestral
The Species Concept In trying to choose best cladograms, taxonomists
use principle of parsimony• Occam’s razor - “One should not make more
assumptions than the minimum needed to explain anything.”
Best cladogram interpreted as that which requires fewest evolutionary changes in taxa involved
The Species Concept Eclectic species concept - single criterion not
sufficient to identify species• Morphological, geographical, biological and ecological
criteria must be used when defining species
Nominalistic species concept - species do not exist• Evolutionary unit of importance local interbreeding
population
Review Introduction Development of the Binomial System of
Nomenclature• Linnaeus• The International Code of Nomenclature for Algae,
Fungi, and Plants Development of the Kingdom Concept Classification of Major Groups The Species Concept