Classification
Why Do Scientists
Classify?
KEY CONCEPT: Biologists use
classification to organize living things
into groups so that the organisms are
easier to study.
 Classification is grouping things together
based on their similarities.
 Taxonomy is the study of classification, or
how living things are grouped.
The Naming System of
Linnaeus
KEY CONCEPT: Carolus Linnaeus devised
a system of naming organisms in which
each organism has a unique, 2 part
scientific name.
 The first part of the name is the Genus. It
is always capitalized.
 The second part of the name is the Species.
It is always in lower case letters.
 Ex.- Felis domesticus
Levels of Classification
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KEY CONCEPT: The more classification
levels that two organisms share, the more
characteristics they have in common.
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A series of 8 levels of classification are used.
The largest group of the most varied organisms is the
Domain.
The smallest, and most specific group is a Species.
Only two of the same species may mate and produce
fertile offspring.
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Domains and Kingdoms
KEY CONCEPT: Organisms are placed into
Domains and Kingdoms based on their cell
type, ability to make food, and the number of
cells in their bodies.
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The 3 Domains are Bacteria, Archae, and Eukarya.
Bacteria are Prokaryotes, have no nucleus, and are
unicellular, some are autotrophs, some are heterotrophs.
Archae are unicellular, are found in hot springs, are
prokaryotes, and either autotrophs or heterotrophs.
Bacteria and Archae differ in their chemical make-up.
Domain Eukarya
KEY CONCEPT: The domain Eukarya can be
further divided into 4 Kingdoms; Protista,
Fungi, Plant, Animal.
 All members of Eukarya have cells that contain
nuclei.
 Protists are unicellular.
 Fungi are multicellular, heterotrophic
(decomposers). Ex.- molds, yeast, fungus,
mushrooms.
 Plants are multicellular, autotrophic.
 Animals are multicellular, heterotrophic.
5 Major Kingdoms:
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Monera
Protista
Fungi
Planta
Animalia
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Unicellular, prokaryotes,
Bacteria
Unicellular, eukaryotes &
algae
Multicellular, absorptive
feeders, decomposers
Muticellular, autotrophs
Muticellular, heterotrophs
Scientific Name:
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Latin
Italics or underlined
Genus species
Homo sapien
Family or Genus Relations?
Family:
 Less closely related
 Larger group
Genus:
 More closely related
 Precedes species=
interbreeding
Family:Felidae
 Lions, tigers,
leopards
 house cats,cheetahs,
ocelots
Genus: Panthera
 Leopards (pardus)
 Lion (leo)
 Tigers (tigris)
Feline Family Members:
Genus: Panthera (Lions &Tigers)
Classification by characteristics:
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Fossil Skulls
DNA Most Useful
Sequences
Hair Samples
Least
Pictures
The Five Kingdoms
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Smaller Sub-Groups
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