taxonomy & classification taxonomy- science of identifying and classifying organisms; all about...
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Taxonomy & Classification
Taxonomy- science of identifying and classifying organisms; all about the naming
Classification- systematic grouping and naming of organisms based on shared similarities
Systematics-
Taxonomy & Classification
Taxonomy- science of identifying and classifying organisms; all about the naming
Classification- systematic grouping and naming of organisms based on shared similarities
Systematics- study of the diversity of life and relationships between organisms
4th century B.C. The Age of Aristotle
•No modern technology
•2 Divisions
•Plants (immobile)
•edible vs. inedible
•Animals (mobile)
•blood vs. bloodless
•walking vs. flying vs. swimming
•Used up through 1600s
•In use through 1600s
1500s to 1600sThe Age of Exploration
• Extensive travel to New World
• Push to collect/classify as many specimens as possible; many newly discovered organisms
• “free for all”- long descriptive names, “folk taxonomy”, duplicate names for same organism, one organism with 2 names, etc.
• Tomato- Solanum caule inermi herbaceo, foliis pinnatis incisis (solanum with the smooth stem which is herbaceous and has incised pinnate leaves)
1700s:The Age of Carolus Linnaeus (born
Carl von Linne)
• “Father of Modern Biological Classification”
• Standardized classification
• Binomial nomenclature (Genus species)
• Hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species
1700s:The Age of Carolus Linnaeus (born
Carl von Linne)• Based on phenetics
• shared physical characteristics
• does not take into account evolutionary relationships, fossils, embryology, behavior, etc.
• Solved “folk taxonomy” problem
• pill bug, sow’s ear, roly poly, sowbug becomes Armadillium vulgare
1700s-1800s: The Age of Microscopy
• Great advances in microscopes
• Ernst Haeckel adds 3rd Kingdom
• From 2 to 3 Kingdoms
• Protista (single-celled eukaryotes and prokaryotes)
• Plantae
• Animalia
• Classification must reflect principle of common descent
• Haeckel coins term phylogeny (classification based on evolutionary relationships)
• “Tree of Life” born
1800s: The Age of Darwin
Early 1900s: The Cladistic Challenge Begins (& continues)
• Clade- group of organisms that share common characteristics and a common ancestor; phylogenetics
• Cladistic analysis- form hypotheses about organismal relationships and test by looking for evidence to support or refute
Early 1900s: The Cladistic Challenge Begins (& continues)• Cladistic analysis
• rely on all available data (morphological, genetic, biochemical, fossil, behavioral, etc.) to test hypothesis• distinguish monophyletic, paraphyletic, polyphyletic
groups
• monophyletic- all members of group share common ancestor
• paraphyletic- some members of group share common ancestor
• polyphyletic- members do not share common ancestor
• Reorganize “Tree of Life” to reflect evolutionary relationships revealed by new evidence
1950s: 3 to 4 to 5 Kingdoms
4 Kingdoms based on phenetics
•Monera (single-celled prokaryotes)
•Protista (single-celled eukaryotes)
•Plantae (mostly autotrophic, multicellular eukaryotes)
•Animalia (multicellular eukaryotes)
(Herbert Copeland)
1950s: 3 to 4 to 5 Kingdoms
5 Kingdoms based on phenetics
•Monera •Protista•Plantae •Fungi •Animalia
(Robert Whittaker)
Mid-late 1900s: The Molecular Age Begins
•Molecular evolution •Molecular clocks•DNA and protein•sequence comparisons
cytochrome c protein sequence alignment
Mid-late 1900s: The Molecular Age•Archaebacteria acknowledged as separate kingdom based on rRNA sequencing (both eukaryote- and prokaryote-like features)(both eukaryote- and prokaryote-like features)
6 Kingdoms •Archaebacteria •Eubacteria•Protista•Plantae•Fungi•Animalia
Based on evolution and molecular genetics (Carl Woese, 1977)
Mid-late 1900s: The Molecular Age
Kingdoms placed into 3 Domains based on molecular genetics (Carl Woese, 1990)
3 Domains •Bacteria•Archaea•Eukarya
Mid-late 1900s: The Molecular Age•Protista further subdivided; many members more like plants or animals than they are each other
8 Kingdoms (and maybe more) •Archaebacteria •Eubacteria•Archaezoa•Protista•Chromista•Plantae•Fungi•Animalia
Based on evolution and molecular genetics
2000 and beyond The Age of Phylogenomics
•Whole genome sequencing•Genome comparisons reveal possible evolutionary relationships•Corroborate horizontal gene transfer•Is it “Tree of Life” or Ring of Life”???•Evidence suggests eukaryotes arose from fusion of archaebacteria with a photosynthetic bacteria•Cladistic analysis continues