Biology
Class Notes
Lesson 30: Classification Systems
Objective: 3.5.1, 3.5.2
Classification
 Grouping of 2 million+ organisms based on shared characteristics.
Taxonomy: The science of identifying, classifying and naming living
things.
The Beginning of Classification
• Aristotle (382-322 B.C.): Greek philosopher who created the first
classification system.
Ex: Plant vs. animal, and whether they flew, walked or swam.
• Carolus Linnaeus (1701-1778): A Swedish botanist who developed a
new classification system based on hierarchy (i.e. levels). *This is the
system used today
Linnaean Taxonomy
• Divided into hierarchical levels:
Domain (largest/most general: eukaryotes, prokaryotes, archaea)
Kingdom
Phylum
(plural=phyla)
Class
Order
Family
Genus (plural=genera)
Species (smallest and most specific group)
Mnemonic: Do Kings Play Chess On Fine Green Silk
Classification of Common Animals
Ex: Domestic Dog Canis lupus familiaris
• Domain:
Eukarya
• Kingdom:
Animalia
• Phylum:
Chordata
• Class:
Mammalia
• Order:
Carnivora
• Family:
Canidae
• Genus:
Canis
• Species:
Canis lupus
• Subspecies:
Canis lupus familiaris
Binomial Nomenclature: A two part naming system developed by Carolus
Linnaeus with the first word being the genus and the second word being a
unique identifier called a specific epithet.
 Three ways to write it are: italics, underlined or in (parentheses) with
only the genus capitalized.
Ex: Homo sapiens, Homo sapiens, or (Homo sapiens).
Kingdoms of the Domain Eukarya (4)
Protista
Protists: Eukaryotic organisms that cannot be classified as fungi, plants or
animals.
• They can be unicellular and multicellular, as well as heterotrophic
and autotrophic.
Fungi (singular = fungus)
• Obtain nutrition by feeding on dead or decaying organic matter.
• Their cell walls contain chitin.
• Mushrooms = Multicellular fungi and yeast = Unicellular fungi.
Plantae
Plants: Multicellular organisms that are photosynthetic autotrophs.
• Their cell walls contain cellulose.
Animalia
Animals: Multicellular and heterotrophic organisms that obtain nutrition
by eating plants or other animals.
• Their cells lack cell walls and chloroplasts.
Classification Chart for Domain Eukarya
(*Copy and memorize this chart.)
Domain Eukarya Summary
Kingdom Protista
Fungi
Plantae
Animalia
Cell
Type
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Cell
Structur
e
Mixed
Cell Wall,
chitin
Cell Wall,
cellulose
No cell wall
Body
Form
Uni and
Multicellular
Uni and
Multicellular
Multicellula
r
Multicellular
Nutrition Auto and
Heterotrophi
c
Heterotrophi
c
Autotrophic
Heterotrophi
c
Phylogeny
 The evolutionary history of a group of organisms.
Phylogenetic Tree: A diagrams that depict relatedness or common
ancestors of a group of organisms.
Dichotomous Key: A tool that can be used to determine the identity of
something by matching characteristics to a series of pair statements or
questions.
Classify Candies Lab
Key Words:
Taxonomy
Species
Domain
Kingdom
Prokaryote
Eukaryote
Autotroph
Heterotroph
Binomial nomenclature
Genus
Phylogeny
Phylogenetic Tree
Dichotomous key