Animal Classification, Phylogeny,
and Organization
Cladistics & Taxonomy
Animal Systematics
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The goal of animal systematics is to arrange animals into groups that reflect evolutionary
relationships.
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How might you group the animals in
the picture?
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One way to group them is by using
phylogenetic systematics, otherwise
known as cladistics.
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Phylogeny refers to the evolutionary
ancestry of animals; how they are
related to a common ancestor.
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Cladistics uses the phylogeny of animals
to group them according to homologous
characters.
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Character – anything with a genetic basis that can
be measured, i.e., anatomy, morphology, or DNA
itself.
Cladistics
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Cladistics focuses on monophyletic groups.
A monophyletic group refers to a single ancestor species
and all of its descendants.
Diagrams called cladograms are used to represent the
phylogeny of organisms.
Characters
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Symplesiomorphy – a homologous character shared by
all members of a monophyletic group.
Synapomorphy – a derived character that has arisen
after a symplesiomorphy visible in a given outgroup.
Groups that share a certain synapomorphy are called a
clade.
Cats are more similar to dogs than they
are to frogs, because they share a more
recent common ancestor with dogs
Practice Cladogram
Construct a Cladogram
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Gorilla
Chimpanzee
Tiger
Lizard
Fish
Tail Lost
Fur
Four Limbs
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Cladogram Showing Vertebrate Phylogeny
Classification
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Organisms can be classified according to their
relatedness to other organisms.
The accepted classifications among scientists are called
taxonomy.
Taxonomy is a hierarchical system. This means that you
start very general and get more specific as you proceed
down the list. Example - The grocery store is set up the
same way!
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Current Biological Classifications
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Kingdom
Phylum
Class
Order
Family
Genus
Species
King
Philip
Came
Over
For
Grape
Soda
Example: Human
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Kingdom
Phylum
Class
Order
Family
Genus
Species
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Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
Binomial Nomenclature
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Bi – 2
Nomen – name
The first name is always the GENUS
The second name is always the SPECIES
Thus, our binomial nomenclature is homo sapiens.
The binomial nomenclature of a house cat is felis catus.
The binomial nomenclature of a killer whale is orcinus
orca.
Example: Dog
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Kingdom
Phylum
Class
Order
Family
Genus
Species
Subspecies
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Animalia
Chordata
Mammalia
Carnivora
Canidae
Canis
lupus
familiaris
The 5 Kingdoms
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Kingdom:
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Monera – true bacteria and cyanobacteria
Protista – eukaryotic, unicellular or colonial, usually motile,
microscopic in size (amoeba, paramecium, etc.)
Plantae – eukaryotic, multicellular, photosynthetic, have cell
walls, nonmotile
Fungi – eukaryotic, multicellular, decomposer, have cell walls,
usually nonmotile
Animalia – eukaryotic, multicellular, heterotrophic, no cell
walls, motile, specialized tissues