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Explore the history and development of the classification system and discuss whether it will remain the same in the future based on information from the class and various factors influencing taxonomy.
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Classification Focus ?? Using information from class, do you believe the classification system will remain the same? WHY or WHY NOT??
Classification: • A way to organize objects or group objects in a logical manner • according to their characteristics and evolutionary history. • Grouping similar objects together • Ex. • Grocery store – fruit, meat, cereal are grouped • Shoe dept. – sneakers: running, cross training, basketball etc…
Reasons to classify: • Universal • Easier to find • Provide information about the organism • Avoid mistakes
Taxonomy • study of classification
Taxonomists: • Scientists who classify organisms:
Taxonomists: • Aristotle – 3 main groups: • air, land, water, • he also grouped plants into three categories, based on differences in their stems.
Taxonomists: • Linnaeus: • developed 7 levels of classification • grouped organisms into hierarchical categories • used an organism’s morphology: its form and structure, to categorize
Linnaeus Cont.: • Linnaeus’s categorization scheme used a hierarchy. • Seven levels of organization, • each more specific than the last, • allowed organisms to be grouped with similar organisms.
Modern day classification system: • Uses 7 taxonomic categories ( developed by Linnaeus): • Each level is called a Taxon • The levels are: • Kingdom – largest category • Phylum • Class • Order • Family • Genus – a group of similar species • Species – most specific category,
Species: • Might tell: 1. What it looks like 2. How it tastes or smells 3. Where it’s found 4. Who discovered it
STOP!!! CK POINT!! Topic: Intro to Classification Date: 4-20-09 • What is the goal of classifying organisms? • Who the 2 taxonomists who are given credit for shaping taxonomy and classifying organisms? • What did each taxonomist contribute to the classification system?
In your packet: • Turn to page 121-122 in the packet • Get a whale text book, ch.17 • Begin answering questions • DO NOT FORGET HMWK DUE WED!!!!
Binomial Nomenclature: • 2 word naming system (scientific name) • Latin, same in every language…universal • 1st word – genus: identifies a group, capitalized • 2nd word – species: share characteristics and reproduce among one another producing fertile offspring • Both are underlinedor italicized • Ex. 1. Acer rubrum Maple Red = red maple tree 2. Acer saccharum Maple sugar = sugar maple trees
Phylogenic tree: • To classify organisms, modern taxonomists consider the phylogeny (fie-LAHJ-uh-nee), or evolutionary history, of the organism • Shows the evolutionary relationships among organisms • Based on several lines of evidence • Fossil record may provide the basis/framework of a phylogenic tree
Modern Classification System Evolutionary Classification: • Grouping organisms based on evolutionary descent or common ancestors • Not limited to physical similarities • Show relationships based on genetic similarities
Taxonomists use: 1. Homologous structures – similar structures, similar development, function is different • Ex. Bird wing and the human arm
Taxonomists use: 2. Analogous structures – structures appear similar, function similar, different development • Ex. Bird wing and the wing of a butterfly
Cladogram: • diagram that shows evolutionary relationships among organisms based on shared derived characteristics • a type of tree showing evolutionary relationships • begin at the bottom and move up • the further away from a common ancestor, the more different their genes
derived character –ADD TO NOTES • Cladistics uses certain features called shared derived characters, • a feature that apparently evolved only within the group under consideration.
Modern Classification System Cont. • Separated into 3 Domains: • Bacteria- Eubacteria • Archaea - Archaebacteria • Eukarya (eukaryotes) - includes protests, fungi, plants, and animals
3 domains: are separates into 6 kingdoms: • Archaebacteria • Eubacteria • Protists • Fungus • Plant • Animal • Vertebrates • Invertebrates
Organism are placed into kingdoms… Organism are placed into kingdoms… • Divided by the following characteristics: • Presence of nucleus • Single or multi celled • Ability to make own food • Ability to move
Kingdom1. Arachaebacteria: : • Unicellular • Some movement • Some make own food = • Some obtain food • from environment = • No nucleus present • Live in hostile environment like Heat, pH
Kingdom: 2. Eubacteria: • Unicellular • Some movement • Some make own food = • Some obtain from environment = • No nucleus present Bacilli (rod), cocci (spherical), spirilla (spiral)
3. Protista: • Unicellular or multi-cellular • some move • some make own food • some obtain food from environment • contain a nucleus
4. Fungi • Some are Unicellular • Most are multi-cellular • Do not move • All fungus obtain food from environment =
5. Plants • Multi-cellular • Do not move • Make own food = • 2 types: • Tracheophytes • Bryophyte
Bryophytes • No true roots, • No true leaves • No true stems • No vascular tissue • ex. mosses
Tracheophytes • true roots, • True leaves, • True stems • have vascular tissue
6. Animal • Multi-cellular • Move • Obtain food • from environment-
Organisms in each kingdom are then classified into the remaining 6 Levels: Kingdom, phylum, class, order, family, genus, specie
Dichotomous Keys: • Also called a field guide, & taxonomic key • Use descriptions about external features to help identify the name of the organism • Arranged with 2 statements describing the organism
Dichotomous Keys Cont: • Using the key gives you the binomial nomenclature (2 word name): genus and specie of the organism • Identifies specific organisms