Taxonomic classification: The ordering and naming of organisms Include images of dichotomous key Carolus Linnaeus (mid-1700s) “God makes them, I name them”
BINOMIAL NOMENCLATURE Genus name & specific epithet Genus begins with uppercase letter Genus & species underlined or in italics E.g., Passer domesticus, P. turkistanicus HIERARCHICAL ORGANIZATION Taxon = group of related organisms
Hierarchical analogies: TAXON ANALOGY DOMAIN Continent KINGDOM Country PHYLUM State CLASS City ORDER Street FAMILY House No. GENUS Family Name SPECIES First Name
SYSTEMATICS: Classification that reflects historical relationships PHYLOGENY: The evolutionary history of taxa Presented as a phylogenetic tree Similar species grouped on branches
Phylogenetic tree
Branches of trees based in fundamental similarities 1) Body symmetry Asymmetry Ancestral multicellular animal
Asymmetry No regular shape sponge
Radial symmetry Sponges Ancestral multicellular animal Radial symmetry Asymmetry Ancestral multicellular animal
Multiple pie-like cuts create similar parts Can also vase-shaped Radial Symmetry Multiple pie-like cuts create similar parts Can also vase-shaped Moon jelly
Longitudinal axis
Bilateral symmetry Jellies Sponges Ancestral multicellular animal Radial symmetry Asymmetry Bilateral symmetry Ancestral multicellular animal
Bilateral Symmetry Have left and right sides Only equally divisible along medial plane
ANTERIOR versus POSTERIOR Front end versus rear end Anterior Posterior
Clam
DORSAL versus VENTRAL Upper versus lower halves Dorsal Ventral
Body segmentation Like slices of bread 1) Unsegmented Roundworms Flatworms unsegmented Jellies Sponges Radial symmetry Asymmetry Bilateral symmetry Ancestral multicellular animal
External segmentation Roundworms Flatworms Jellies Sponges Radial symmetry unsegmented External segmentation Asymmetry Bilateral symmetry Ancestral multicellular animal
Obvious, like a loaf of bread Segmented worms Arthropods
External segmentation 3) Internal segmentation Roundworms Arthropods Segmented worms Flatworms Jellies Sponges Radial symmetry External segmentation Asymmetry Bilateral symmetry Internal segmentation Ancestral multicellular animal
Must look inside Endoskeleton, muscles, nerves
External segmentation Skeleton 1) Exoskeleton Roundworms Segmented worms Arthropods Flatworms Jellies Exoskeleton Sponges Radial symmetry External segmentation Asymmetry Bilateral symmetry Internal segmentation Ancestral multicellular animal
Exoskeleton Hard skeleton outside, muscles inside E.g., insects, crustaceans
External segmentation 2) Endoskeleton Roundworms Segmented worms Arthropods Flatworms Jellies Exoskeleton Sponges Radial symmetry External segmentation Asymmetry Bilateral symmetry Internal segmentation Endoskeleton Ancestral multicellular animal Chordates
Endoskeleton Hard skeleton inside, muscles outside
Snails and clams = shell Turtles and crustaceans= carapace Final word on “SHELLS” Snails and clams = shell Turtles and crustaceans= carapace Protists & sea urchins = test Chiton shells have 8 plates Dorsal view Ventral view