Used a hierarchical system

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Linnaeus System of Taxonomy

• Used a hierarchical system
• Kingdom, Phylum, Class, Order, Family, Genus,
  Species (later Domain was added)
• Based on molecular evidence (DNA and protein
  sequences) its accepted to have 6 Kingdoms and
  have added 3 Domains

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• Latinized descriptive names of organisms
  -Binomial Nomenclature 2 word scientific
  naming system
• First part of binomial Genus Always
  capitalized
• Second part species - always lower case.
• Latin scientific names are always italicized (if
  word processing) or underlined (if hand written)
• Ex. Homo sapiens, wise man
• species specific group of 1 type of organism
  that may interbreed and produce viable, fertile
  offspring.

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Binomial Nomenclature Who cares?

• What do you call this?
• Crawdad?
• Crawfish?
• Crayfish?
• Prairie crayfish-Procambarus gracilis

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Why use Binomial Nomenclature?

• Problems with common names
• Varies from area to area, therefore, no
  commonality.
• Does not specify a particular species.
• Each animal has an unique binomial name.
• Required for all animals by International Code of
  Zoological Nomenclature.

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Domain Archaea Domain Eubacteria

• Prokaryotic microbes, tiny
• Live in extreme environments high temps, salts,
  acids (tough)
• Anaerobic
• Most primitive

• Prokaryotic microbes
• Often called the true bacteria
• Live in most environments
• Anaerobic or aerobic

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Domain Eukarya

• Eukaryotic
• Mainly aerobic but can be anaerobic
• Includes all other kingdoms (Protista, Plant,
  Fungi, Animal)

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6 Kingdoms
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Common Animal Phylum
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What is this?
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Most recently described Phylum - Cycliophora

• 36th found Phylum in 1995
• In the Animal Kingdom
• Symbion pandora
• Found in mouthparts of Norwegian lobsters
• 0.3 mm long 300 µm

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• Currently we use
• Morphological, biochemical, fossil, and molecular
  comparisons to infer evolutionary relationships

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• Though sedimentary fossils are the most common
• Paleontologists study a wide variety of fossils

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Morphological and Molecular Homologies

• In general, organisms that share very similar
  morphologies or similar DNA sequences
• Are likely to be more closely related than
  organisms with vastly different structures or
  sequences.
• Not always true! Analogy vs. Homology

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Homology

• Homologous Structures structures in different
  species that are similar because of commons
  ancestry.

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Analogy

• Analogous Structures similarity in structures
  due to adaptations and not a common ancestor.

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Cladograms
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Cladistics

• a method that applies the scientific method to
  the construction of evolutionary relationships.

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Cladogram

• Diagram showing how organisms are related based
  on shared, derived characteristics
• such as
• vertebrae
• jaw bones
• four legs
• amniotic eggs
• hair

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Cladogram Vocabulary

• Branch point
• 2 species differ in shared derived characters
• Ingroup
• monophyletic group we are interested in
• Outgroup
• species or group of species that is most closely
  related to an ingroup

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Primate Cladogram
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• Each branch point
• Represents the divergence (separation) of two
  species

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• What shared derived character is common to
• salmon
• lizard
• rabbit
• but not the lamprey?

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Constructing a cladogram

• Choose species
• Choose characters
• Each character has different character states
  (example tail or no tail)
• Determine order of character states
• primitive or derived?
• Use the fossil record
• Many simple parts came before fewer, more
  specialized parts
• Vestigial organs not functioning but present)
• Mutation rate of DNA nucleotides
• Group species (or higher taxa) based on shared
  derived characteristics

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Constructing a cladogram

• Build a cladogram based on
• All species are placed on tips in the
  phylogenetic tree, not at branch points
• Each cladogram branch point should have a list of
  one or more shared derived characters that are
  common to all species above the branch point
  unless the character is later modified
• All shared derived characters appear together
  only once in a cladogram unless they arose
  independently during evolution more than once
• Choose the most likely cladogram among possible
  options

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Construct a Cladogram for Us! Lets use the
characters of tail, fur, and of limbs
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Gorilla

• Four limbs
• Fur
• No tail

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Tiger

• Four limbs
• Fur
• Tail

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Lizard

• Four limbs
• Tail

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Fish

• Tail

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Chimpanzee

• Four limbs
• Fur
• No tail

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Clade With 4 Limbs
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Clade With Fur
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Clade With No Tail
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Characteristics (Traits) for Constructing this
Cladogram

• Tail is the most ancestral
• Four limbs is the oldest derived trait
• Fur is a later derived trait
• Loss of tail is the most derived trait

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One Possible Cladogram
Gorilla
Chimpanzee
Tiger
Lizard
Fish
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A Vertebrate Cladogram
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• The outgroup comparison
• Enables us to focus on just those characters that
  were derived at the various branch points in the
  evolution of a clade.

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