Classification of Living Things

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Classification of Living Things
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CHAPTER 17

• CLASSIFICATION
• Grouping organisms based on their characteristics

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Taxonomy - the branch of biology that names and
groups organisms according to their
characteristics and evolutionary history
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The Greek philosopher Aristotle is known to
have grouped living things as either plants or
animals over 2,000 years ago.
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In the mid 1700's Carolus Linnaeus a Swedish
naturalist devised a system of grouping
organisms into hierarchical categories.
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Major Classification Levels Kingdom -
Kings Phylum play Class - cards Order -
on Family - fat Genus - green Species - stools
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Classification of Modern Humans Kingdom
Animalia Phylum Chordata Class Mammalia
Order Primates Family Hominidae Genus Homo
Species Homo sapiens
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Kingdom Animalia
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Phylum Chordata
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Class Mammalia
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Order Primates
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Family Homidinae
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Genus Homo
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Species Homo sapiens
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Scientific Names unique two-word name given to
each kind of organism on Earth
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The first word of the scientific name is the
genusThe second word of the scientific name is
the species
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Felis jacobita
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Felis margarita scheffeli
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Felis rufus
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Felis nigripes
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Felis domesticus
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Rules when writing scientific names.1. Always
capitalize the genus name and use a lower case
letter for the species.2. Both parts of the
scientific name are written in italics or
underlined. Rhea darwinii Rhea
darwinii
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Scientific names vs common names You probably
understand what I mean when I say, "I'm going to
the creek to sit under a post oak tree and catch
some perch". A biologist would want me to say,
"I'm going to the creek to sit under a Quercus
stellata and catch some Lepomis macrochirus".
Why? Because not everyone attaches the same
common names to the same organism. Actually, a
perch is not a perch at all. It is a "sunfish".
And many people call a post oak tree a
"blackjack".
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Binomial nomenclature a two name system for
writing scientific names. The genus name is
written first (always Capitalized). The
species name is written second (never
capitalized). Both words are italicized or
underlined.
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"Formally written" scientific names almost always
have a third part, known as the authority. The
authority is written as an abbreviation of the
last name of the person responsible for naming
the organism. Since Carolus Linnaeus was the
first person to name so many plants, the L. for
Linnaeus is very common in plant scientific
names. An example is Quercus alba L.
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• Some examples of scientific names
• Canis familiaris - dog
• Felis domesticus - cat
• Canis lupus - wolf
• Vulpes vulpes - fox
• Ichthyomyzon gagi - brook lamprey
• (the species ending ( i ) indicates that this
  animal is named for its discoverer)
• Populus deltoides - cottonwood
• Diospyros virginiana - persimmon

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Phylogeny the evolutionary history of an
organism, is the cornerstone of a branch of
biology called systematic taxonomy.
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Systematics as systematic taxonomy is commonly
called, organizes the diversity of living things
into the context of evolution. A phylogenetic
tree is a family tree that shows a hypothesis
about the evolutionary relationships thought to
exist among groups of organisms.
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CHAPTER 18

• Cladogram
• Cladistic analysis identifies and considers
  only those characteristics of organisms that are
  evolve or arise over time
• Used to construct a cladogram
• Used as a tool to understand how one lineage of
  organism branched from another in the course of
  evolution

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CHAPTER 18
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CHAPTER 18

• MAKE A CLADOGRAM
• backbone legs hair
• absent absent absent
  earthworm
• present absent absent
  trout
• present present absent
  lizard
• present present present
  human

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CHAPTER 18
LIZARD
TROUT
HUMAN
EARTHWORM
HAIR
LEGS
BACKBONE
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CHAPTER 18

• CLASSIFICATION DATA
• BASED ON
• DNA AND RNA SIMILARITIES
• MOLECULAR CLOCK DNA CAN MARK THE PASSAGE OF
  TIME BY LOOKING AT MUTATIONS

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CHAPTER 18

• KINGDOMS AND DOMAINS
• THREE DOMAINS
• EUKARYOTA PROTISTS, FUNGI, PLANTS, AND ANIMALS
• BACTERIA KINGDOM EUBACTERIA
• ARCHAEA KINGDOM ARCHAEBACTERIA

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CHAPTER 18

• BACTERIA ARCHAEA EUKARYOTA
• prokaryote prokaryote eukaryote
• peptidoglycan no pept. No pept.
• unicellular unicellular both
• auto/hetero auto/hetero auto/hetero