Transcript Classification Lecture

Classification
Chapter 18
2006-2007
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 Cougar
ex: Starfish, dragonfly
ex:“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:
Taxons
Kingdom
Phylum
Class
Order
Family
Genus
Species
general
specific
(Kings play chess on fine gold squares)
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
Eukaryote
Classification
 6 Kingdom system

Prokaryote
Prokaryotes
 No separate organelles in their cells
 Bacteria
 Archaebacteria

Eukaryotes
 Separate organelles




in their cells
Protists
Plants
Fungi
Animals
Regents Biology
Bacteria
&
Archaebacteria
Figure 18-12 Key Characteristics of
Kingdoms and Domains
Taxon Characteristics
Section 18-3
Classification of Living Things
DOMAIN
Bacteria
Archaea
KINGDOM
Eubacteria
Archaebacteria
CELL TYPE
Eukarya
Protista
Fungi
Plantae
Animalia
Prokaryote
Prokaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Cell walls with
peptidoglycan
Cell walls
without
peptidoglycan
Cell walls of
cellulose in
some; some
have
chloroplasts
Cell walls of
chitin
Cell walls of
cellulose;
chloroplasts
No cell walls
or chloroplasts
Unicellular
Unicellular
Most unicellular;
some colonial;
some
multicellular
Most
multicellular;
some
unicellular
Multicellular
Multicellular
MODE OF
NUTRITION
Autotroph or
heterotroph
Autotroph or
heterotroph
Autotroph or
heterotroph
Heterotroph
Autotroph
Heterotroph
EXAMPLES
Streptococcus,
Escherichia coli
Methanogens,
halophiles
Amoeba,
Paramecium,
slime molds,
giant kelp
Mushrooms,
yeasts
Mosses, ferns,
flowering
plants
Sponges,
worms,
insects, fishes,
mammals
CELL
STRUCTURES
NUMBER OF
CELLS
Organizing systems
 Making sense out of the differences
Eastern gray squirrel
Regents
Sciurus
Biology
carolinensis
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
Regents Biology
Modern Classification
• Just using appearance is not enough.
• New system uses:
1. Fossils
2. Dissections/comparative anatomy
3. Molecular similarities/DNA/enzymes
4. Evolutionary similarities or
developmental milestones
Ex: 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
What are the Derived
Traits in this cladogram?
What could the ancestral
trait be?
Which organisms share the trait of claws/nails?
Which organism doesn’t have any of the traits?
Which organisms are more closely related?
- Perch and pigeon
- Pigeon and chimp