2006-2007
Classification
Chapter 18
What is Classification?
• System to organize ALL living things into groups with biological meaning.
•Taxonomy: The study of classification.
Assigning a Name
Problem: Common names can vary among languages. Common name is misleading. Descriptions are too long to be a name.
ex: Mountain Lion or Puma or Cougarex: Starfish, dragonflyex:“Oak with deeply divided leaves that have no
hairs on their undersides and no teeth around their edges.”
Solution: Latinized and Greek words are commonly used to avoid any language issues. Reduce the number of words to a two part name.
Carolus Linnaeus• The Linnean system where each
species has a 2 part (scientific) name:
BIONOMIAL NOMENCLATURE• genus• Species
(Genus is 1st word, species is 2nd)
Homo sapiens• means “wise man”• perhaps in a show of hope &
optimism
Genus groupings
• Classify organisms into broader groups• Species that are closely related are
grouped into the same genus– Leopard Panthera pardus– African lion Panthera leo– Tiger Panthera tigris
Classification System
• Linnaeus’ hierarchical system:Kingdom
general
Phylum
Class
Order
Family
Genus
Species specific
((KKings ings pplay lay cchess hess oon n ffine ine ggold old ssquares)quares)
Taxons
Kingdoms and Domains
Modern groups are six kingdoms: Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia
Domains – newest, largest inclusive category developed from comparing r-RNA subunits. Bacteria, Archaea, Eukarya
So…, classification sequence is now:D, K, P, C, O, F, G, S
Cladogram comparing Domains
Regents Biology
Bacteria&
Archaebacteria
Classification 6 Kingdom system
Prokaryotes No separate organelles in their cells Bacteria Archaebacteria
Eukaryotes Separate organelles
in their cells Protists Plants Fungi Animals
Prokaryote
Eukaryote
DOMAIN
KINGDOM
CELL TYPE
CELL STRUCTURES
NUMBER OF CELLS
MODE OF NUTRITION
EXAMPLES
Bacteria
Eubacteria
Prokaryote
Cell walls with peptidoglycan
Unicellular
Autotroph or heterotroph
Streptococcus, Escherichia coli
Archaea
Archaebacteria
Prokaryote
Cell walls without peptidoglycan
Unicellular
Autotroph or heterotroph
Methanogens, halophiles
Protista
Eukaryote
Cell walls of cellulose in some; some have chloroplasts
Most unicellular; some colonial; some multicellular
Autotroph or heterotroph
Amoeba, Paramecium, slime molds, giant kelp
Fungi
Eukaryote
Cell walls of chitin
Most multicellular; some unicellular
Heterotroph
Mushrooms, yeasts
Plantae
Eukaryote
Cell walls of cellulose; chloroplasts
Multicellular
Autotroph
Mosses, ferns, flowering plants
Animalia
Eukaryote
No cell walls or chloroplasts
Multicellular
Heterotroph
Sponges, worms, insects, fishes, mammals
Eukarya
Classification of Living Things
Section 18-3
Figure 18-12 Key Characteristics of Kingdoms and DomainsTaxon Characteristics
Regents Biology
Organizing systems Making sense out of the differences
Eastern gray squirrelSciurus carolinensis
Regents Biology
Organizing the world of organsims The Tree of Life
organize creatures by structure & function how they are built how they live
organize them into groups of closely related creatures
Modern Classification
• Just using appearance is not enough.• New system uses:
1. Fossils 2. Dissections/comparative anatomy3. Molecular similarities/DNA/enzymes4. Evolutionary similarities or developmental milestonesEx: amniotic sac, jaws, endothermic
Cladistics
• Classifying organisms according to the order that they diverged from a common ancestor.1. Ancestral characters – found in all groups
2. Derived characters – found in some groups
ex: backbone is an ancestral trait found in all birds and mammals
ex: hair is a derived trait found in only mammals
Vertebrate Cladogram
Which organisms are more closely related? -Perch and pigeon-Pigeon and chimp
Which organisms share the trait of claws/nails?
Which organism doesn’t have any of the traits?
What are the Derived Traits in this cladogram?
What could the ancestral trait be?