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

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Construct a Cladogram

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Gorilla Chimpanzee

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 Kingdom King Phylum Philip Class Came Order Over Family For Genus Grape Species Soda

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