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

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 – spongesCnidaria – jellyfish, coralsPlatyhelminthes – tapewormsNematoda – roundwormsAnnelida – segmented worms earthwormsMollusca – oysters, snails, octupusArthropoda – spiders, crabs, bugsEchinodermata – 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