Biological Classification
Group the following in any way
you would like,
but justify your grouping!
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Frogs
Bears
Ants
Spiders
Bacteria
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Humans
Dolphins
Sharks
Mushrooms
Pine Trees
Why do we Classify?
• To group organisms according to
similarities
• Taxonomy is the science of classifying
organisms.
Binomial Nomenclature
• Binomial Nomenclature - the formal system of naming
species. (Bi = two, nomial = names)
– Latin is the language in which scientific names are written.
• Carolus Linnaeus (1707 – 1778) a Swedish botanist ,
came up with the b.n. system.
• Aristotle was the first scientist to group organisms based
on physical characteristics.
The 3 Domains
Archaea
The Five
The Three Domains
Kingdoms
Eubacteria
Eukaryota
The 5 Kingdoms
Monera
Fungi
Protista
The Five
Kingdoms
Animalia
Plantae
7 Levels of Classification
1 is Largest- 7 is Smallest
1. Kingdom
2.Phylum
7. Species
7 Levels of
Classification
6. Genus
5. Family
3. Class
4. Order
Examples of Classification
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Common Pond Amoeba
KINGDOM: Protista
PHYLUM: Sarcomastigophora
CLASS: Sarcodina
ORDER: Granulopodea
FAMILY: Amoebidae
GENUS: Amoeba
SPECIES: Amoeba proteus
Examples of Classification
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Humans
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Primata
FAMILY: Hominidae
GENUS: Homo
SPECIES: Homo sapiens
Scientific Names
• The GENUS is the 1st word in the scientific
name. Always capitalized
Example : Amoeba proteus
Homo sapiens
• The SPECIES is the 2nd word in the
scientific name. Always lowercase
Example: Amoeba proteus
Homo sapiens
Phylogenetic Tree
• A Phylogenetic Tree is a way to organize living things
and show how they are related.
Cladograms
• Cladograms are a way to show shared or lost
traits between related organisms
How do we know how to
classify?
• Similar Structures
• Similarities in
genes (DNA
– The bones in a
bat’s wing are
sequence or
almost the same as
proteins)
the bones in a
human hand
• Similar Behaviors
– All mammals nurse
their young
– Human and
Primate DNA is
99% similar
Evidence for
Classification/Evolution
• Homologous
structures: similar
bone structures in
different organisms
• Fossil Record: Past
organisms can be
studied through
fossils
• Gene similarities:
matching DNA
sequences
• Embryology: similar
development patterns
in unborn species of
different species
• Hybridization: ability
to successfully
interbreed different
species.
Homologous Structures
Embryology
Hybridization