CHAPTER 18 CLASSIFICATION (Taxonomy) THE SIX KINGDOMS

HISTORY OF TAXONOMY  TAXONOMY –BRANCH OF BIOLOGY THAT NAMES AND GROUPS ORGANISMS ACCORDING TO THEIR CHARACTERISTICS AND EVOLUTIONARY HISTORY

ARISTOTLE  TWO KINGDOMS HE KNEW WERE PLANT AND ANIMAL  WHY?  USED COMMON NAMES TO DESCRIBE ORGANISMS;  PROBLEM – COMMON NAMES NOT THE SAME WORLDWIDE OR EVEN REGION WIDE

ARISTOTLE  LATIN THE LANGUAGE USED TO NAME ORGANISMS  LATIN – LANGUAGE OF SCHOLARS

LINNAEUS The Father of Taxonomy  CAROLOS LINNAEUS –SWEDISH BOTANIST/NATURALIST –  DEVISED A SYSTEM OF GROUPING ORGANISMS INTO HIERARCHIAL CATEGORIES  USED ORGANISM’S MORPHOLOGY TO CATEGORIZE IT

Three Domain System  Domain Archaea  Domain Bacteria  Domain Eukarya  A domain is a broad group that living things are classified into on the basis of mRNA analysis.

LEVELS OF CLASSIFICATION  KINGDOM – LARGEST CATEGORY  PHYLUM – SUBSET OF KINGDOM  CLASS – SUBSET OF PHYLUM  ORDER – SUBSET OF CLASS  FAMILY – SUBSET OF ORDER  GENUS – SUBSET OF FAMILY  SPECIES – SINGLE ORGANISM TYPE

BINOMIAL NOMENCLATURE  TWO-NAME NAMING SYSTEM  LATIN  SCIENTIFIC NAME – GENUS AND SPECIES NAME  EX: Drosopholus melongaster  CAPITALIZE GENUS NAME, SPECIES NAME IS LOWER CAPS;  UNDERLINE OR PUT IN ITALICS;

MODERN CLASSIFICATION  MODERN TAXONOMISTS AGREE THAT THE PHYLOGENY OR EVOLUTIONARY HISTORY OF AN ORGANISM BE USED TO CLASSIFY AN ORGANISM.  SYSTEMATICS – ORGANIZES THE TREMENDOUS DIVERSITY OF LIVING THINGS IN THE CONTEXT OF EVOLUTION

PHYLOGENETIC TREE  A FAMILY TREE THAT SHOWS THE EVOLUTIONARY RELATIONSHIPS THOUGHT TO EXIST AMONG GROUPS OF ORGANISMS.  REPRESENT A HYPOTHESIS  BASED ON SEVERAL LINES OF EVIDENCE

Phylogenetic Tree

PHYLOGENETIC TREE  EVALUATE AN ORGANISMS MORPHOLOGY BASED ON:  SIMILAR LIVING ORGANISMS  POSSIBLE ANCESTRAL ORGANISMS IN FOSSIL RECORD  DNA  EMBRYOLOGICAL DEVELOPMENT

CHROMOSOMES & MACROMOLECULES  MOLECULAR CLOCK – THE NUMBER OF AMINO ACID DIFFERENCES IS A CLUE TO HOW LONG AGO TWO SPECIES DIVERGED FROM A SHARED EVOLUTIONARY ANCESTOR;

Molecular Clock

KARYOTYPE COMPARISON  REGIONS OF CHROMOSOMES THAT HAVE THE SAME PATTERN OF BANDING ARE CLUES TO THE DEGREE OF RELATEDNESS OF ORGANISMS;

CLADISTICS USES SHARED DERIVED CHARACTERISTICS TO ESTABLISH EVOLUTIONARY RELATIONSHIPS; DERIVED CHARACTER – FEATURE THAT APPARENTLY EVOLVED IN THE GROUP UNDER CONSIDERATION; EX. BIRD FEATHERS EVOLVED WITHIN BIRDS AND NO OTHER GROUP;

DERIVED CHARACTERISTICS  STRONG EVIDENCE OF COMMON ANCESTRY BETWEEN ORGANISMS THAT SHARE THEM;  CLADOGRAMS – DIAGRAMS MADE FROM CLADISTIC ANALYSIS THAT SHOW ANCESTRY

Cladogram

CLADISTICS CONCLUSIONS  LEAD TO NONTRADITIONAL CONCLUSIONS:  BIRDS, CROCODILES & ALLIGATORS ARE MORE CLOSELY RELATED TO EACH OTHER THAN TO SNAKES OR LIZARDS;  REPTILES ARE A COMPOSITE OF SEVERAL BRANCHES OF VERTEBRATES;

THE MODERN SYSTEM OF CLASSIFICATION  SIX KINGDOM SYSTEM:  ARCHAEBACTERIA  EUBACTERIA  PROTISTA  FUNGI  PLANTAE  ANIMALIA

ARCHAEBACTERIA  UNICELLULAR PROKARYOTES  DISTINCTIVE CELL MEMBRANES  UNIQUE BIOCHEMICAL & GENETIC PROPERTIES  AUTOTROPHIC (CHEMOSYNTHETIC)  LIVE IN HARSH ENVIRONMENTS  “ANCIENT” BACTERIA

ARCHAEBACTERIA  THERMOACIDOPHILES – HIGH HEAT AND LOW PH, LIVE IN HOT SPRINGS,  HALOPHILES – SALT-LOVERS, LIVE IN DEAD SEA, GREAT SALT LAKE  METHANOGENS – LIVE IN INTESTINAL TRACTS OF ANIMALS, SEWAGE TREATMENT PLANTS, PRODUCE METHANE CH4

EUBACTERIA  “TRUE” BACTERIA  UNICELLULAR PROKARYOTES  MOST AEROBIC  CAN BE: HARMLESS PATHOGENIC

ARCHAEBACTERIA & EUBACTERIA  REPRODUCE BY BINARY FISSION  RAPID EVOLUTIONARY RESPONSE TO ENVIRONMENTAL CHANGE  I.E., ANTIBIOTIC RESISTANCE

PROTISTA  EUKARYOTIC  MOSTLY SINGLE-CELLED ORGANISMS  REQUIRE WATER (MOISTURE) TO LIVE  EX. Euglena, Amoeba, Paramecium, Water molds, Slime molds, Algae  Catch-All Kingdom

Fungi  Eukaryotic  External Heterotrophs  Secrete enzymes to break down food source & absorb food into body of fungi  Unicellular (yeast)  Multicellular (mushrooms)  Cell walls made of chitin

Plantae  Eukaryotic  Autotrophic  Multicellular  Non motile  Cell walls with cellulose  Photosynthesis to obtain energy  Food stored as starch  Reproduce sexually

Plantae Non Vascular Plants  Lack vascular tissue  Lack true roots, stems, leaves  Low growing  Absorb water and nutrients  Mosses  Ferns

Plantae Vascular Plants  True roots, stems, leaves  Water moves upward from roots

Gymnosperms  Conifers  Seeds born on cones  Mostly wind pollinated  Evergreen  Pines, spruce, fir, cedar, cypress, sequoia

Angiosperms  Flowering plants  Seeds develop within enclosed ovaries  Leaves modified into flowers,  Flowers pollinated by wind or animals

Angiosperms – Flowering Plants  Two Divisions:  Monocotyledons (monocots) – single seed leaf  Lilies, corn  Dicotolyledons (dicots) – two seed leaves  Rose, maples,

Animalia  Eukaryotic  Heterotrophic  Multicellular  Movement  Organized into tissues and organs (most animals)

Animalia Invertebrates Porifera – sponges Cnidaria – jellyfish, corals Platyhelminthes – tapeworms Nematoda – roundworms Annelida – segmented worms earthworms Mollusca – oysters, snails, octupus Arthropoda – spiders, crabs, bugs Echinodermata – sea stars

Animalia Vertebrates  Phylum Chordata Urochordata – sea squirt Cephalochordata - lancelets Vertebrata – fish, sharks, amphibians, reptiles, birds, mammals

What is a Chordate?  In some stage of its life: Dorsal, hollow nerve cord Notochord Pharyngeal pouches Tail extending beyond anus