Taxonomy is the practice and science of categorization or classification. In a wider, more general sense, it may refer to a categorization of things or concepts, as well as to the principles underlying such a categorization.
1. Classification & Introduction to Taxonomy
2. Classification • The grouping of objects or information based on similarities • There are more than 1 million described species of plants and animals – Many millions still left undescribed
3. • Science of classification (grouping things) – Process of classifying biodiversity based on evolutionary relationships – Means to organize biological diversity – Groups and names organisms based on different characteristics
4. Early Taxonomic Systems • Aristotle (350 B.C.) – Developed the 1st widely accepted system of biological classification – Everything grouped as plant or animal Plants Animals Herbs Shrubs Trees Land Sea Air
5. Early Taxonomic Systems • Carolus Linnaeus (1753)- use of a species name • Based on looking at physical and structural similarities • Revealed relationships of organisms • Binomial nomenclature • Gave each species 2 names (scientific name) • Genus and species • Genus is a group of similar species • Developed the modern system of taxonomy
6. • Latin was the language used (no longer used and is not being changed) – Genus name always capitalized – species name always lowercase – both names MUST be underlined or italicized – Ex: Canis lupus (wolf) – Ex: Homo sapiens (human)
7. • Ex: Felis domesticus (housecat) –Felis domesticus var. • Indicates more than one variety
8. • Scientific names are often: – Descriptive (Acer rubrum red maple) – Named after someone (genus Linnea) – Descriptive of where an organism lives (D. californica) – Named after person who first described the organism (D. californica Torr) • Many organisms have common names – Can be misleading – Can have more than 1 common name, depending on the area it is found in
9. Modern Taxonomy • Now based on evolutionary relationships • Taxonomists study: – Structural similarities – Chromosomal structure (karyotypes) – Reproductive potential – Biochemical similarities • Comparing DNA and amino acids – Embryology/development – Breeding behavior – Geographic distribution
10. 7 taxonomic categories: Kingdom largest, most general group Phylum called a division with plants Class Order Family Genus Species smallest, most specific group • Grouped genera into families, families into orders, orders into classes, classes into phyla, and phyla into kingdoms • Species can interbreed with each other
11. 1969: 5-Kingdom System • Monera, Protista, and Fungi kingdoms added to the 2 established kingdoms • Kingdoms defined based on 2 main characteristics • Possession of a true nucleus (prokaryote or eukaryote) • How it gets food – Heterotroph – Autotroph – Decomposer
12. 1980’s: 3-Domain System • Bacteria have distinct differences • All eukaryotic kingdoms grouped into one domain (Eukarya) • Monera kingdom split into 2 domains (Archaea and Eubacteria)
13. How Living Things are Classified • Groups of organisms called taxa or taxons • Organisms arranged in groups ranging from very broad to very specific characteristics – Broader taxons have more general characteristics and more species within it – Smallest taxon Species – Largest taxon Kingdom
14. • a family tree for the evolutionary history of a species – The root of the tree represents the ancestral lineage – Tips of the branches represent descendents of the ancestor – Movement upward shows forward motion through time – Speciation: split in the lineage – Shown as a branching of the tree
15. Cladistics • System of classification based on phylogeny • Derived characteristics/traits: appear in recent parts of a lineage but not in older members
16. Cladogram • A branching diagram to show the evolutionary history of a species • Helps scientists understand how one lineage branched from another in the course of evolution
17. Dichotomous Key • Way of identifying organisms by looking at the physical characteristics • Uses a series of questions to group into a hierarchy classification
18. The Six Kingdoms of Organisms Prokaryotes: – Microscopic – Prokaryotic (Lack a nucleus) – Can be autotrophs (photosynthetic or chemosynthetic) or heterotrophs – Unicellular
19. • 2 kingdoms (Archaebacteria and Eubacteria) – Archaebacteria live in extreme environments like swamps, deep-ocean hydrothermal vents (oxygen- free environments) • Cell walls not made of peptidoglycan • Ex: Methanogens, Halophiles – Eubacteria live in most habitats • Cell walls made of peptidoglycan • Ex: E. coli, Streptococcus, cyanobacteria
20. The Six Kingdoms of Organisms – Eukaryotic (has a nucleus) – Some have cell walls of cellulose • Some have chloroplasts – Can be autotrophs or heterotrophs (some can be fungus-like) – Most are unicellular; some are multicellular or colonial – Ex: amoeba, paramecium, slime molds, euglena, kelp – Lacks complex organ systems – Lives in moist environments
21. The Six Kingdoms of Organisms Fungi • Eukaryotes • Cell walls of chitin • Heterotrophs • Most multicellular; some unicellular • Ex: mushrooms, yeast • Absorbs nutrients from organic materials in the environment • Stationary
22. The Six Kingdoms of Organisms • Eukaryotes • Cell walls of cellulose • Autotrophs • Multicellular • Photosynthetic contains chloroplasts • Ex: mosses, ferns, trees, flowering plants • Cannot move • Tissues and organ systems
23. The Six Kingdoms of Organisms • Eukaryotes • Do not have a cell wall or chloroplasts • Heterotrophs • Multicellular • Ex: sponges, worms, insects, fish, mammals (nurse young) • Mobile
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