2 History of Taxonomy Aristotle Taxonomy – the branch of biology which names and groups organisms according to their characteristicsAristotleFirst person to put organisms ingroups.- Grouped animals into land, airor water dwellers.At first, Aristotle’s system seemed adequate.When many new organisms were discovered,scientists began having problems. More groupswere needed. Common names were different fromplace to place and caused confusion and did notdescribe the organism.
3 History of taxonomy cont. Linnaeus created a new system of grouping organisms.Based on their morphology (structure)Created 7 levels of classificationAlso created a two-part namingsystem called BinomialNomenclature.Linnaeus
4 The 7 Levels of Classification Linnaeus devised seven levels of organization.Kingdom: the largest group of living things.Phylum: The largest group within a kingdom.Class: The largest group within a phylum.Order: The largest group within a class.Family: Largest group in an order.Genus: Largest group in a family.Species: Smallest group of living things.
5 Wait.. What were those again? No Looking!KingdomPhylumClassOrderFamilyGenusSpecies
6 Binomial Nomenclature The species name, also called the scientific name of an organism has two parts.The Genus nameThe species identifierThe Genus name is capitalized, the species name is lower case and both are underlined or written in italics (typing only)Thus, our scientific name is written as such Homo sapiens or Homo sapiens.The full scientific name of a species will contain thethe names of each classification group the organism isin.For Humans:Kingdom: AnimaliaPhylum: ChordataSubphylum: VertebrataClass: MammaliaOrder: PrimataFamily: HominidaeGenus: Homospecies: sapiens
7 The Six KindomsAll life on Earth has been divided into six different kingdoms.Kingdom ArchaebacteriaUnicellular prokaryotesCell membranes are different from other bacteria.Many live in harsh environments.Kingdom Eubacteria:These are the ones which affect you: tooth decay, food poisoning, disease, create food products like yogurt.
8 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.
9 The Six Kingdoms cont. Kingdom Fungi Multicellular, eukaryotic, heterotrophicAbsorb nutrients – digest outside their bodyIncludes mushrooms, puffballs, rusts, smuts, mildews, and molds
10 The Six Kingdoms cont. Kingdom Plantae Multicellular, eukaryotic, autotrophicMake their own food through photosynthesisInclude mosses, ferns, conifers, and flowering plants
11 The Six Kingdoms cont. Kingdom Animalia Eukaryotic, heterotrophic, multicellularCan move around in their environmentInsects, mammals, reptiles, amphibians, fish, birds, worms
12 The 3 Domain SystemScientists have added another classification group ABOVE the level of KingdomMolecular biology has shown that all organisms naturally fall into 3 large groups which are called DomainsDomain BacteriaContains the Kingdom EubacteriaDomain ArchaeContains the Kingdom ArchaebacteriaDomain EukaryaContains all Kingdoms with Eukaryotic cellsProtista, Fungi, Plantae, Animalia
13 based upon specific traits. TaxonomySo how do we put allthese organisms intogroups?Today, scientists useeither Systematics orCladistics to putorganisms into groupsbased upon specific traits.Systematics – Organizes the diversity of living things in the context of evolution.Creates a Phylogenetic Tree – A family tree which shows the evolutionary relationships thought to exist 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.
14 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.