Classification

Linnaeus’s System of Classification Kingdom Phylum Class Order Family Genus Species Linnaeus was the scientist who developed scientific naming system. Taxonomy – identifying, classifying organisms,and assigning scientific names. Classification is a way to organize living things into groups according to characteristics. Why use a scientific name? Because many organisms have several common names that vary due to region or cultures and it becomes confusing… Ex. Puma, cougar, panther, mountain lion, ghost cat – all the same animal… …But the scientific name stays the same no matter where you go Ex. Felis concolor is the scientific name for a mountain lion. How to write a scientific name: Genus species Notice only the first letter is capitalized while everything else is lowercase. Both words must be underlined unless written in cursive or italics, then no underline is used. Comprise scientific name aka binomial nomenclature Domain comes before Kingdom!

Grizzly bearBlack bearGiant panda Red fox Abert squirrel Coral snake Sea star KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER Carnivora FAMILY Ursidae GENUS Ursus SPECIES Ursus arctos Classification of Ursus Arctos All encompassing – many organisms at Kingdom level Only ONE organism at Species level As you move down the levels, the animals become more and more specific to the level King Philip Came Over For Good Soup

Classification and Phylogeny The goal is to have classification evolutionary relationships Biologists use phylogenetic trees to depict hypotheses about the evolutionary history of a species and reflect the hierarchal classification of groups

Classification and Phylogeny How are phylogenetic trees made? Look at homologous structures (structures that may vary in form and function, but have similarities because they evolved from the same structure in a common ancestor – ie, whale flipper, bat wing, etc – bones develop from same tissues and have the same bones in those limbs) The greater the number of homologous structures between two species, the more closely related they are. Can now also use DNA to compare amino acid sequences

Panthera pardus (leopard) Species Genus Felidae Order Carnivora Family Canis Lutra Panthera Mephitis Canidae Mustelidae Canis lupus (wolf) Canis latrans (coyote) Lutra lutra (European otter) Mephitis mephitis (striped skunk)

Classification and Cladistics In cladistics, organisms are grouped by common ancestry. Being able to look at DNA changed how we classified organisms A clade consists of an ancestral species and all its evolutionary descendants and forms a distinct branch in the tree of life

Hair, mammary glands Long gestation Gestation Duck-billed platypus Iguana Outgroup (reptile) Ingroup (mammals) Beaver Kangaroo

Classification and Cladistics Cladistics has changed the traditional classification of some organisms, including the relationships between dinosaurs, birds, crocodiles, lizards and snakes

Lizards and snakes Crocodilians Saurischian dinosaurs Ornithischian dinosaurs Pterosaurs Birds Common ancestor of crocodilians, dinosaurs, and birds

PHYLOGENETIC TREES CLADOGRAM AppendagesConical Shells Crab Barnacle Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton Segmentation Tiny free-swimming larva Phylogenetic Trees vs. Cladograms Incorrect ! Based on “looks” of organisms Ancestor

Phylogenetic Trees vs. Cladograms PHYLOGENETIC TREES CLADOGRAM AppendagesConical Shells Crab Barnacle Limpet Crab Barnacle Limpet CrustaceansGastropod Molted exoskeleton Segmentation Tiny free-swimming larva Ancestor Correct! Sessile Based on Evolutionary Path and DNA = derived character – characteristics that appear in recent lineage, but not in older members.

Classification: A Work in Progress Phylogenetic trees are hypotheses about evolutionary history. They are revised, and in some cases rejected, as new evidence is found. Being able to compare DNA has really enabled us to challenge traditional classifications and remodel phylogenetic trees.

Classification: A Work in Progress In the late 1900s, DNA and cladistics led to the development of a three- doman system, recognizing two domains of prokaryotes (Bacteria and Archaea) one domain of eukaryotes (Eukarya)

Kingdom Animalia Domain Archaea Earliest organisms Domain Bacteria Domain Eukarya Kingdom Fungi Kingdom Plantae The protists (multiple kingdoms)

Key Characteristics of Kingdoms DOMAIN KINGDOM CELL TYPE CELL STRUCTURES NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals Eukarya Classification of Living Things Both Bacterial Kingdoms

are characterized by such as and differing which place them in which coincides with which place them in which is subdivided into Living Things * Kingdom Eubacteria * Kingdom Archaebacteria Eukaryotic cells Prokaryotic cells Important characteristics Cell wall structures Domain Eukarya Domain Bacteria Domain Archaea * Kingdom Plantae * Kingdom Protista * Kingdom Fungi * Kingdom Animalia Bacteria! NO nucleus Nucleus 6 Kingdoms!

Cladograms of Six Kingdoms Kingdoms Eubacteria Archaebacteria Protista Plantae Fungi Animalia DOMAIN EUKARYA DOMAIN ARCHAEA DOMAIN BACTERIA Bacteria Protista Plantae FungiAnimalia