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Classification
Chapter 18
18.1 Finding Order In Diversity
Why do you think we would need to classify?
To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner.
Why Classify?
Taxonomy:A discipline where scientists classify
organisms and assign each organism a universally accepted name
Why Classify?
Depending on where you are this animal could be called a mountain lion, puma, cougar or a panther– all of which are common names
However the scientific name is Felis concolor
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Assigning Scientific Names
Using scientific names made it easier to give one name to one animal because common names have very different meanings in different areas or they are just different all around.
Binomial Nomenclature
Carolus Linnaeus A Swedish botanist During the early 18th Century (1707-1778), he
created a 2 word naming system
Binomial Nomenclature
Each species is assigned a 2-part scientific nameAlways written in italicFirst word is capitalizedSecond word is lower cased
Ex: Grizzly Bear is called Ursus arcotos
Binomial Nomenclature
First part of the name is the genus the animal belongs to
Genus:Group of closely related species
Second part of name is unique to each species within a genus
Linnaeus’ System of Classification
Linnaeus’ hierarchical system of classification includes 7 levels
From largest to smallest:Kingdom, Phylum, Class, Order, Family,
Genus, Species
Linnaeus’ System of Classification
Taxon:Each level or group of organization into which
organisms are classified.
Kingdom:Largest taxonomic group. Most inclusive of
closely related phyla
Linnaeus’ System of Classification
Phylum:Several different classes make up a phylum:
they are closely related
Class:Composed of similar orders, larger categories
Linnaeus’ System of Classification
Order:Broad taxonomic categories composed of
similar families
Family:Group of genera that share the same
characteristics
18.2 Evolutionary Classification
Phylogeny: Evolutionary relationship among organisms
Biologists now group organisms into categories that represent lines of evolutionary descent, or phylogeny not just physical similarities.
Evolutionary Classification
Evolutionary ClassificationStrategy of grouping organism together based
on their evolutionary history
The higher the level of taxon, the farther back in time is the common ancestor of all the organisms in the taxon
Classification Using Cladograms Derived characters
Characteristics that appear in recent parts of a lineage but not in its order members
CladogramDiagram that shows the evolutionary
relationships among a group of organisms
Characteristics/ Traits
Organisms Crab
Barnacle
Molted External Skeleton
Segmentation
Limpet
Tiny free flowing Larvae
Items to the left: organisms has it
Items to the right: organism does not have it
Similarities in DNA and RNA
The gene of many organisms show important similarities at the molecular level.
Similarities in DNA can be used to help determine classification and evolutionary relationships.
18.3 Kingdom and Domains
5 KingdomsMonera, Protista, Fungi, Plantae and Animalia
6 KingdomsBiologists came to recognize that the Monera
were composed of 2 distinct groups
Kingdoms and Domains
As a result, Monera have been separated into 2 kingdoms: Eubacteria and Archeabacteria
Eubacteria, Archeabacteria, Monera, Protista, Fungi, Plantae and Animalia
The 3 Domain System
Domain: A more inclusive category than any other larger than
a kingdom
Domain Eukarya is composed of Protista, Fungi, Plantae, and Animalia
Domain Bacteria is composed of Eubacteria Domain Archaea is composed of Archaebacteria
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
Domain Bacteria
Unicellular and prokaryotic Cell walls with peptidogylcan
Domain Archaea
Unicellular and Prokaryotic
Cell walls with out peptidogylcan
Live in some of the most extreme environments you can imagine
Domain Eukarya
Consists of all organisms that have a nucleus Protista:
Composed of eukaryotic
organisms that cannot be
classified as animals,
plants or fungi Members share great
variety
Domain Eukarya
Fungi: Heterotrophs: most
feed on dead or decaying matter
They secrete digestive enzymes on food and absorb food molecules
Domain Eukarya
Plante:Multicellular, photosynthetic autotrophsCone-bearing and flowering plants, mosses
and fernsCells have cell walls
Domain Eukarya
Animalia:Multicellular heterotrophsCell walls have no cell wallsThey move for part of their lives