Classification Systems How are living things classified?! Learning Goals 12, 13, 14, 15 & 16 on your rubric! TAXONOMY: The study of classification, or how living things are grouped! Aristotle classified organisms more than 2,000 years ago (see ex. p24).! Carolus Linnaeus introduced a system based on similar structures of organisms (all have wings, six legs, etc.) Binomial/Scientific Names Latin two-word naming system Linnaeus used to name species; still used today!genus is the first word in a scientific name & identifies a group of similar species!second word identifies the species- often tells something about the organism- what it looks like, where it is found, or who discovered it!examples: Lathyrus odoratus (smelly flower), Pinus virginiana (Pine tree found in Virginia), Felis domesticus (domestic cat) Why use scientific names? 1.To avoid mistakes (common names can be confusing); Latin is universal 2.To show that organisms in the same genus are related 3.To describe the organism 4.To allow information to be organized easily
!5 How to Write Latin Names Click to edit Master text styles Human Example: Homo sapien! Three Rules for Writing Scientific Names: capitalize first word (genus), lowercase second word (species), underline both words Today s Classification System! Four things considered when classifying a new organism & determining its history:! Fossil Record! DNA: Hereditary Information! Similar Structures of Organisms (Homology)! Embryology Embryology- study of organisms in the early stages of development Can you tell the human from the embryo? You had a tail! Homologous Structures: structures that are similar in structure &/or origin These appendages do very different jobs and look very different from the outside but have all the same bones in the same order!
Homologous (similar) Structures in Plants Cladograms: a branching diagram to show relationships among organisms!10 These are all examples of leaves that are modified to do very unique jobs for a variety of plants. How we organize groups of life: Eight Levels of Taxonomy (taxons from largest to smallest) The larger the group, the more organisms are included but the less they have in common! Today s Classification System! Separates organisms into 6 kingdoms! s are the most familiar taxon! The smallest taxonomic category is species! Organisms that belong to the same species can mate and produce fertile offspring (fertile means able to reproduce)! Dogs of any breed are the same species Canis (lupus) familiaris so different breeds can reproduce and those offspring ( mutts ) can also reproduce
Ferns Examples of Members of the Animal (YES, we are animals!) Moss Animalia Complex cells Multicellular Heterotrophs No cell wall Plantae Complex cells -- Multicellular Autotrophs have cell walls Giant Ocean Sea Kelp Athlete s Foot is caused by fungi mold Mushrooms Pond Life (mostly microscopic) Fungi Complex cells Both Uni & Multicellular (without special structures) Heterotrophs Have cell walls This kingdom is a hodge-podge- for things that are animal-like or plantlike but don t fit into either category- Protista (odds & ends) Complex cells Both Uni (usually) & Multicellular Some Hetero, some Autotrophs Some have cell wall, some
Archaea (Archaebacteria) (Domain Archaea) Simple & Unicellular Autotrophs Have a cell wall Live in extreme environments where nothing else can live Found in the Geysers at Yellowstone Eubacteria ( true bacteria ) Domain Eukarya Simple & Unicellular Some Hetero, some Autotrophs Have cell wall Found everywhere In the Dead Sea!20 Tools to help identify organisms Field Guide: books that describe & illustrate organisms Dichotomous Key: detailed lists of identifying characteristics Who is this?