Scientific Classification
Why Classify? Biologists must organize living things into groups that have biological meaning. Use classification system to name organisms and group them in a logical manner.
Taxonomy Discipline in which scientists classify organisms and assign each organism a universally accepted name. Organize them into groups that have biological significance. Why might we need universally accepted name?
Write first bird that pops into your head
Write the first Hawk that comes into your head
Common Names Not good for biologists due to different languages and different regions containing the same animals. Shared common names leads to confusion – i.e. Buzzard
Describe this…
First attempts Scientists described the physical characteristics – Up to 20 words long! Very confusing, no template existed – Scientists describe different things
Binomial Nomenclature Developed by Carolus Linnaeus Each species is assigned two-part scientific name. Always written in italics – First word capitalized, second lowercased – First word= genus Second word= unique characteristic Escherichia coli (E. coli)
Linnaeus’s System of Classification Consists of levels (hierarchical) Seven levels Each level called a taxon (taxonomic category)
Kingdom Highest taxonomical rank made up of similar phylum – 6 present kingdoms Anamalia, Plantae, Fungi, Protista, Archaea, and Bacteria
Phylum Includes many different organisms that share important characteristics i.e. Chordata – Share features in their body plan and internal functions
Class Taxon containing similar orders i.e. Mammalia – Animals that are warm-blooded, have body hair, and produce milk for their young
Order Taxon containing similar families i.e. Carnivora – Ursidae, Canidae, Felidae, etc.
Family Taxon containing similar genera i.e. Ursidae – Ursus and Ailuropoda
Genus Group of closely related species i.e. Ursus – Ursus maritimus, Ursus arctos, Ursus americanus, Ursus thibetanus
Species Group of similar organisms that can breed and produce fertile offspring i.e. Ursus maritimus
A bit of an example for ya
Kingdom Communication Device
Phylum Communicates Voice
Class Telephone
Order Cell Phone
Family Smart Phone
Genus Droid
Species Razr
Kings Play Chess On Fiber Glass Stools
Make an anagram KPCOFGSKPCOFGS SGFOCPKSGFOCPK
Who selects the members of a species? – Nature depends who can mate Who selects members of other levels? – We do How do we select the characteristics on which to base grouping?
Phylogeny The study of evolutionary relationships among organisms. Groupings now represent lines of evolutionary descent—not just physical similarities! – Dolphins, whales versus sharks
OR?
Evolutionary relationships Species in a genus are more closely related to one another than in another genus. – Share a recent, common ancestor All genera in a family share a common ancestor.
Evolutionary Relationships The higher the level of the taxon, the further back in time the common ancestor of all the organisms in the taxon. Organisms may not appear similar, but are.
Similarities in DNA & RNA Even organisms with very different anatomies have common traits. Every organism uses DNA & RNA to – Pass information – Control growth and development Allow for comparison of organisms at most basic level
Similar Genes Starkly different organisms show surprising similarities – i.e. humans and yeast both code for myosin Similarities between genes prove common ancestor
Similar Genes Starkly different organisms show surprising similarities – i.e. humans and yeast both code for myosin Similarities between genes prove common ancestor