Animal Classification, Phylogeny, and Organization Cladistics & Taxonomy

Animal Systematics  The goal of animal systematics is to arrange animals into groups that reflect evolutionary relationships.  How might you group the animals in the picture?  One way to group them is by using phylogenetic systematics, otherwise known as cladistics.  Phylogeny refers to the evolutionary ancestry of animals; how they are related to a common ancestor.  Cladistics uses the phylogeny of animals to group them according to homologous characters.  Character – anything with a genetic basis that can be measured, i.e., anatomy, morphology, or DNA itself.

Cladistics  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  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

7 Construct a Cladogram

8 GorillaChimpanzee Tiger Lizard Fish Four Limbs Fur Tail Lost

Cladogram Showing Vertebrate Phylogeny

Classification  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  KingdomKing  PhylumPhilip  ClassCame  OrderOver  FamilyFor  GenusGrape  SpeciesSoda

Example: Human  Kingdom  Phylum  Class  Order  Family  Genus  Species  Animalia  Chordata  Mammalia  Primates  Hominidae  Homo  sapiens

Binomial Nomenclature  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  Kingdom  Phylum  Class  Order  Family  Genus  Species  Subspecies  Animalia  Chordata  Mammalia  Carnivora  Canidae  Canis  lupus  familiaris

The 5 Kingdoms  Kingdom:  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