Taxonomy Organizing and naming organisms according to biological

Taxonomy • Organizing and naming organisms according to biological similarities – Based on • Evolutionary history • Developmental similarities • RNA and DNA similarities

Carolus Linnaeus • Composed the system of binomial nomenclature used to name organisms today

Binomial Nomenclature • Two name classification system –Ex. Human –Homo sapiens –Genus Species

Classification System • Kingdom- Broad grouping • Phylum- Few similar characteristics • Class- More similar characteristics • Order- Many shared characteristics • Family- Very closely related • Genus- Almost alike- Wolf - Coyote • Species- Identical organisms

Cladograms • Taxonomic classification based on evolutionary history –Organisms with similar evolutionary advancements are grouped together irregardless of their appearance • See page 452

Cladograms • Ex. A dog and a fox both have similar tooth structure, DNA, body plan, and developmental characteristics

Quick Lab p. 453 • Construct the cladogram at the bottom of the page.

Similarities in DNA • Sometimes similar organisms are not as closely related as one might think • Ex. Two types of bird, both vultures, look very similar but one urinates on their legs to cool their blood and the other does not. Even though they look similar an analysis of their DNA shows a very distant relationship

Similarities in DNA • One vulture lives in the Americas while the other lives in Africa. • An American stork displays the same behavior and DNA analysis shows that they are more closely related than the two vultures

Molecular Clocks • Mutations occur at a relatively constant rate among all species for the same gene. • In comparison of species the more mutations that differ the longer ago two species diverged from one another

New Classification System • Instead of the older 5 classification system most biologists now accept a 6 classification system. • This is due to differences in bacteria that have been studied in greater detail

New Classification System • The kingdom Monera has been divided into Eubacteria and Archaebacteria due to differences in metabolism and evolutionary differences.

Domains • More broad classification than kingdoms • 3 domains – Bacteria – Archaea – Eukarya

Bacteria • Unicellular • No nucleus • Have cell walls surrounding a cell membrane • Cell walls contain peptidoglycan

Archaea • Unicellular • No nucleus • No peptidoglycan in cell wall • Live in extreme environments • Contain unusual lipids that other bacteria do not contain

Eukarya • Composed of –Protista –Fungi –Plantae –Animalia

Protista • Most single celled except for multicellular algae • Can be autotrophic or heterotrophic • Can have plant, fungi, and animal like characteristics

Fungi • All heterotrophic • Digest food outside of the organism • Most are multicellular • Yeasts are unicellular

Plantae • Multicellular • Photosynthetic autotrophs • Non motile • Contain cell walls

Animalia • Heterotrophic • No cell walls • Most are motile • Very diverse group