Taxonomy and Cladistics

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Taxonomy and Cladistics

• How are organisms grouped and organized?

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Taxonomy

• Identifying, naming, and classifying species
• Why does everything need a scientific name?
• Catfish Crayfish Silverfish

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Linnaean System

• Two-part Latin name for each species
• Species categorized into broader and broader
  groups
• According to similar characteristics

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Salamander Classification
Kingdom Anamalia Eukaryotic, multicellular, heterotrophic, motile
Phylum Chordata Having a backbone or nerve cord
Class Amphibia Both kinds of life (water and land)
Order Caudata Salamander characteristics (absence of middle ear, large footplate, presence of ribs and teeth, etc)
Family Plethodontidae (1 of 10) Lungless
Genus Ensatina Sword-shaped (teeth)
Species Eschscholtzii Named for Johann Eschscholtz
(subspecies) Oregonensis Belonging in state of Oregon
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Taxonomy
Humans Red-th. Loon No.
Cardinal
Carl Linnaeus 1735 - 1758
Domain Eukarya Eukarya Eukarya Kingdom Animali
a Animalia Animalia Phylum Chordata
Chordata Chordata Class Mammalia Aves
Aves Order Primates Gaviiformes
Passeriformes Family Hominidae
Gaviidae Cardinalidae Genus Homo
Gavia Cardinalis Species sapiens
stellata cardinalis
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Classification and Evolution

• Species can be shown as groups within groups in a
  phylogenetic tree
• phylogeny means evolutionary history
• Each branching point represents a common ancestor
  of the species above the point

May be slanted or bracket style
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Understanding Phylogenetic Trees
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Clades and Cladograms (aka phylogenetic trees)

• A clade is a grouping that includes a common
  ancestor and all the descendents of that ancestor

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All organisms in a clade share homologous
characters (traits) that unite the organisms as a
group.
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Create a Cladogram

• You will create a cladogram by
• Organizing shared traits
• Creating a venn diagram
• Creating a cladogram

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Misconceptions Addressed

• Evolutionary relationships are like trees, not
  ladders

• At the first speciation event in this cladogram,
  one lineage led to mosses, the other to the fern,
  pine, and rose
• Living moss species are not ancestral to other
  land plants--they are cousins!

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• For any speciation event, it does not matter
  which lineage goes to the right and which to the
  left
• Biologists often put the clade they are most
  interested in on the right side

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Did Humans Come from Chimps?

• Humans did not evolve from chimpanzees.
• Humans and chimpanzees share a common ancestor
  that was neither human nor chimpanzee