Transcript Taxonomy
Taxonomy Bio 250 History of Taxonomy • Taxonomy – the branch of biology which names and groups organisms according to their characteristics Aristotle •First person to put organisms in groups. - Grouped animals into land, air or water dwellers. •At first, Aristotle’s system seemed adequate. •When many new organisms were discovered, scientists began having problems. More groups were needed. Common names were different from place to place and caused confusion and did not describe the organism. History of taxonomy cont. • Linnaeus created a new system of grouping organisms. – Based on their morphology (structure) – Created 7 levels of classification – Also created a two-part naming system called Binomial Nomenclature. Linnaeus The 7 Levels of Classification • Linnaeus devised seven levels of organization. Species: Genus: Smallest Largest group group ofin living a of family. things. Phylum: Kingdom: Order: Family: The The the Largest largest largest largest group group group within within in an living order. aaphylum. class. kingdom. things. Class: The largest group within a Wait.. What were those again? Kingdom Phylum Class No Looking! Order Family Genus Species Binomial Nomenclature • The species name, also called the scientific namename of ofana species organism has The full scientific will contain the two the names of each classification group the organism is parts. in. – The Genus name For Humans: – The species identifier Kingdom: Animalia Phylum: Chordata – The Genus name is capitalized, the species Subphylum: Vertebrata name is lower case and both are underlined Class: Mammalia Order: in Primata or written italics (typing only) Family: Hominidae Genus: Homo – Thus, our scientific name is written as such species: sapiens Homo sapiens or Homo sapiens. The Six Kindoms • All life on Earth has been divided into six different kingdoms. • Kingdom Archaebacteria – Unicellular prokaryotes – Cell membranes are different from other bacteria. – Many live in harsh environments. • Kingdom Eubacteria: – Unicellular prokaryotes – These are the ones which affect you: tooth decay, food poisoning, disease, create food products like yogurt. The Six Kingdoms cont. • Kingdom Protista – The catch-all Kingdom. If it’s eukaryotic and not a plant, animal or fungus, it’s in here. – Mostly unicellular but do have some multicellular species. – Some are plantlike and some are animalike. The Six Kingdoms cont. • Kingdom Fungi – Multicellular, eukaryotic, heterotrophic – Absorb nutrients – digest outside their body – Includes mushrooms, puffballs, rusts, smuts, mildews, and molds The Six Kingdoms cont. • Kingdom Plantae – Multicellular, eukaryotic, autotrophic – Make their own food through photosynthesis – Include mosses, ferns, conifers, and flowering plants The Six Kingdoms cont. • Kingdom Animalia – Eukaryotic, heterotrophic, multicellular – Can move around in their environment – Insects, mammals, reptiles, amphibians, fish, birds, worms The 3 Domain System • Scientists have added another classification group ABOVE the level of Kingdom • Molecular biology has shown that all organisms naturally fall into 3 large groups which are called Domains – Domain Bacteria • Contains the Kingdom Eubacteria – Domain Archae • Contains the Kingdom Archaebacteria – Domain Eukarya • Contains all Kingdoms with Eukaryotic cells • Protista, Fungi, Plantae, Animalia Taxonomy • Systematics – Organizes So how do we the putdiversity all of living things the context of evolution. thesein organisms into – Creates a Phylogenetic Tree – A family tree groups? which shows the evolutionary relationships Today, use thought to exist scientists among groups of organisms. • A phylogenetic tree represents a hypothesis. • Scientists use morphology (structure), patterns of embryological development, similarity in DNA and proteins to construct phylogenetic trees. either Systematics or Cladistics to put organisms into groups based upon specific traits. Taxonomy cont. • Cladistics – uses certain features of organisms called shared derived characters to establish evolutionary relationships. – Derived Characters – are features that apparently evolved only within the group under consideration. – Ex: If you’re studying birds, a derived character may be feathers. – Scientists believe that if a group shares a character not shared with any other group, then they likely inherited it from a common ancestor. – Cladogram – Ancestry diagram made by means of cladistics.