Linnaeus’ System of Taxonomy Used a hierarchical system Kingdom, Phylum, Class, Order, Family, Genus, Species (later Domain was added) Based on molecular evidence (DNA and protein sequences) its accepted to have 6 Kingdoms and have added 3 Domains

Latinized descriptive names of organisms - Binomial Nomenclature: 2 word scientific naming system First part of binomial – Genus – Always capitalized Second part – species - always lower case. Latin scientific names are always italicized (if word processing) or underlined (if hand written) Ex. Homo sapiens, “wise man” species – specific group of 1 type of organism that may interbreed and produce viable, fertile offspring.

Binomial Nomenclature – Who cares? What do you call this? Crawdad? Crawfish? Crayfish? Prairie crayfish-Procambarus gracilis

Why use Binomial Nomenclature? Problems with common names Varies from area to area, therefore, no commonality. Does not specify a particular species. Each animal has an unique binomial name. Required for all animals by International Code of Zoological Nomenclature.

Domain Archaea Domain Eubacteria Prokaryotic microbes, tiny Live in extreme environments: high temps, salts, & acids (tough) Anaerobic Most primitive Prokaryotic microbes Often called the “true bacteria” Live in most environments Anaerobic or aerobic

Domain Eukarya Eukaryotic Mainly aerobic but can be anaerobic Includes all other kingdoms (Protista, Plant, Fungi, Animal)

6 Kingdoms

Common Animal Phylum

What is this?

Most recently described Phylum - Cycliophora 36th found Phylum in 1995 In the Animal Kingdom Symbion pandora Found in mouthparts of Norwegian lobsters 0.3 mm long = 300 µm

Currently we use Morphological, biochemical, fossil, and molecular comparisons to infer evolutionary relationships

Though sedimentary fossils are the most common Paleontologists study a wide variety of fossils (a) Dinosaur bones being excavated from sandstone (g) Tusks of a 23,000-year-old mammoth, frozen whole in Siberian ice (e) Boy standing in a 150-million-year-old dinosaur track in Colorado (d) Casts of ammonites, about 375 million years old (f) Insects preserved whole in amber (b) Petrified tree in Arizona, about 190 million years old (c) Leaf fossil, about 40 million years old

Morphological and Molecular Homologies In general, organisms that share very similar morphologies or similar DNA sequences Are likely to be more closely related than organisms with vastly different structures or sequences. Not always true! Analogy vs. Homology

Homology Homologous Structures – structures in different species that are similar because of commons ancestry.

Analogy Analogous Structures – similarity in structures due to adaptations and not a common ancestor.

Cladograms

Cladistics a method that applies the scientific method to the construction of evolutionary relationships.

Cladogram Diagram showing how organisms are related based on shared, derived characteristics such as: vertebrae jaw bones four legs amniotic eggs hair

Cladogram Vocabulary Branch point Ingroup Outgroup 2 species differ in shared derived characters Ingroup monophyletic group we are interested in Outgroup species or group of species that is most closely related to an ingroup

Primate Cladogram

Each branch point Represents the divergence (separation) of two species

What shared derived character is common to: salmon lizard rabbit but not the lamprey?

Constructing a cladogram Choose species Choose characters Each character has different character states (example: tail or no tail) Determine order of character states primitive or derived? Use the fossil record Many simple parts came before fewer, more specialized parts Vestigial organs –not functioning but present) Mutation rate of DNA nucleotides Group species (or higher taxa) based on shared derived characteristics

Constructing a cladogram Build a cladogram based on All species are placed on tips in the phylogenetic tree, not at branch points Each cladogram branch point should have a list of one or more shared derived characters that are common to all species above the branch point unless the character is later modified All shared derived characters appear together only once in a cladogram unless they arose independently during evolution more than once Choose the most likely cladogram among possible options

Construct a Cladogram for Us Construct a Cladogram for Us! Let’s use the characters of tail, fur, and # of limbs

Gorilla Four limbs Fur No tail

Tiger Four limbs Fur Tail

Lizard Four limbs Tail

Fish Tail

Chimpanzee Four limbs Fur No tail

Clade With 4 Limbs

Clade With Fur

Clade With No Tail

Characteristics (Traits) for Constructing this Cladogram Tail is the most ancestral Four limbs is the oldest derived trait Fur is a later derived trait Loss of tail is the most derived trait

One Possible Cladogram Gorilla Chimpanzee Tiger Lizard Fish Tail Lost Fur Four Limbs

A Vertebrate Cladogram Birds Mammals Reptile Amphibian Fish Four Limbs Amniotic Egg Endothermic Fur Feathers Vertebrae Lancelet Outgroup

The outgroup comparison Enables us to focus on just those characters that were derived at the various branch points in the evolution of a clade. Salamander TAXA Turtle Leopard Tuna Lamprey Lancelet (outgroup) 1 Hair Amniotic (shelled) egg Four walking legs Hinged jaws Vertebral column (backbone) Amniotic egg Vertebral column (a) Character table. A 0 indicates that a character is absent; a 1 indicates that a character is present. (b) Cladogram. Analyzing the distribution of these derived characters can provide insight into vertebrate phylogeny. CHARACTERS