Taxonomy

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TaxonomyThe Study of Classification
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What do you think?

• What does classification mean?
• Why is classification important?
• When do we use classification systems in our
  everyday lives?

Books at the library, iPods and movies, even
people!
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Objectives

• Learn about the history of classification
  systems
• Recognize Linnaeus contribution
• Discuss classification keys and their usefulness
• Study Phylogenic trees and Cladograms
• Outline the 6 Kingdom system

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What exactly is classification?

• Classification is a branch of Biology called
  Taxonomy.
• Taxonomy classifies based on similarities
• but it wasnt always this way!

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Meet Aristotle (350 BC)

Aristotle classified all living organisms as
either a plant or an animal. He further
classified animals by where they lived, and
plants by their size.
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Aristotles Classification Scheme

• ALL LIVING ORGANISMS

PLANTS
ANIMALS
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PLANTS
SHORT (Herbs) MEDIUM
(Shrubs) TALL (Trees)
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ANIMALS
LAND
WATER
AIR
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What are some problems with this classification
system?

• Some animals live in more than one habitat during
  their lives.
• Most plants start small and grow larger.

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These problems were recognized by Carolus
Linnaeus
The Father of Modern Taxonomy
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Carolus Linnaeus

• Linnaeus was a Swedish botanist who lived in the
  18th century.
• He decided to classify organisms based on their
  visible similarities and differences in structure.

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Carolus Linnaeus

• Linnaeus made three huge contributions to modern
  taxonomy
• Using structural criteria for classification
• Establishing the 7 taxa currently used.
• Created the Binomial Nomenclature

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The 7 Taxa
Pneumonic Device King Phillip Came Over For Gin
ger Snaps

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Used in Scientific Names
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7 Taxa
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Did you notice?

• As you go down through the 7 taxa, you get more
  and more details about the organism you are
  looking at.
• Organisms get more and more similar from top to
  bottom.

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Lets Classify Us!

• Lets classify a human
• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Primates
• Family Hominidae
• Genus Homo
• Species Sapiens

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Binomial Nomenclature

• Binomial nomenclature is a two word naming
  system.
• The first term describes the organisms genus
  while the second term describes the species.

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Genus and Species

• Organisms placed in the same genus have similar
  structures (look the same).
• Organisms with the same species name are so
  similar they would be able to reproduce under
  normal circumstances to produce fertile offspring.

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Binomial Nomenclature

• Scientific names are written in Latin and have
  something to do with the organisms
  characteristics or where they live. (Castor
  canadensis) (Ursus horribilus)
• Scientific names are written in italics or
  underlined.
• The first term is always capitalized while the
  second isnt
• Example Homo sapiens ? humans
• Homo sapiens
• H. sapiens

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Examples of Scientific Names

• Canis lupus ? Wolf
• Canis familiaris ? Dog
• These organisms are structurally similar (same
  genus) but different species (cannot reproduce
  under normal circumstances to produce fertile
  offspring)

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Scientific Names

• Equus caballus - horse
• Equus asinus donkey
• When a donkey and a horse reproduce, their
  offspring is a mule, which is sterile. (1 in 100
  000 will have an offspring)

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Check out the Scientific Names
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KEY TERMS

• SYSTEMATICS
• Scientific study of the diversity of organisms
  and their natural (evolutionary) relationships
• A systematist seeks to reconstruct phylogeny

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KEY TERMS

• PHYLOGENY
• Evolutionary history of a species or other
  taxonomic group
• MONOPHYLETIC
• Said of a group consisting of organisms that
  evolved from a common ancestor

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KEY TERMS

• CLADISTICS
• Classification of organisms based on recency of
  common ancestry rather than degree of structural
  similarity

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Cladistics

• Cladists emphasize phylogeny by focusing on when
  evolutionary lineages (lines of descent) divide
  into two branches
• Cladists develop cladograms

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KEY TERMS

• CLADOGRAM
• A diagram that illustrates evolutionary
  relationships based on the principles of
  cladistics

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Building a Cladogram
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Characters
TAXON
VASCULAR TISSUES
SEEDS
FLOWERS
Moss
A
A
A
Fern
P
A
A
Pine
P
P
A
P
P
P
Daisy
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Pine
Daisy
Moss
Fern
Common ancestor with vascular tissues
Node 1
Common plant ancestor
(a) All of the plant groups shown here except
mosses have vascular
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Pine
Daisy
Moss
Fern
Node 2
Common ancestor with vascular tissues
Node 1
Common plant ancestor
(b) Seeds are a shared character for all plant
groups shown here except mosses and ferns.
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Pine
Daisy
Moss
Fern
Node 3
Common seed- producing ancestor
Node 2
Common ancestor with vascular tissues
Node 1
Common plant ancestor
(c) Of the plant groups shown here, only the
daisy produces flowers.