classification. why classify? –to study the great diversity of organisms, biologists must give...
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ClassificationClassification
Why Classify?Why Classify?
– To study the great diversity of organisms, biologists must give each organism a name.
– Biologists must also attempt to organize living things into groups that have biological meaning.
Assigning Scientific NamesAssigning Scientific Names
– History• 18th century scientists recognized problem with
naming organisms by their common names– cougar, puma, panther, mountain lion– UK: buzzard hawk, US: buzzard vulture
Why all the weird names?Why all the weird names?
• 18th century scientists understood Latin and Greek
Early efforts at naming organismsEarly efforts at naming organisms
• 1st attempts at naming organisms often described physical characteristics– PROBLEMS
• some names were 20 words long• Different scientists described different
characteristics
Binomial NomenclatureBinomial Nomenclature
– (Carolus Linnaeus ~ Swedish botanist)• Two word naming system
– 1st word is capitalized, 2nd is lowercased and italicized– 1st part GENUS / 2nd part special character or
location
Linnaeus’s System of Linnaeus’s System of ClassificationClassification
– Taxonomy taxonomic levels or taxon (taxa: plural)
• Seven levels: • Kingdom• Phylum• Class• Order• Family• Genus• Species
• Kingdom ~ King
• Phylum ~ Phillip
• Class ~ Came
• Order ~ Over
• Family ~ For
• Genus ~ Great
• Species ~ Soup
Grizzly bear (Ursus Grizzly bear (Ursus arctosarctos))
• Genus: Ursus group of closely related species• Contains 5 other kinds of bear including Ursus
maritimus.• 2nd part: arctos / maritimus is unique to species
within genus (important trait or indication of where the organism lives ~ maritimus: sea)
– Giant Panda differs enough to be placed in its own genus• Ailuropoda
Grizzly bear (Ursus Grizzly bear (Ursus arctosarctos))
• Genera that share many characteristics, such as Ursus & Ailuropoda, are grouped into families ~ (Ursidae)
• These bears together with 6 other families of meat-eating animals, (dogs: canidae and cats: felidae are in order Carnivora.
• Carnivora is grouped into class mammalian (worm-blooded, body hair, milk) which also includes order primates (humans, apes, monkeys, prosimians)
• Class mammalian is grouped with birds (aves), reptiles, amphibians, and all fish into a phylum: Chordata.
TaxonomyTaxonomy
Linnaeus only named two kingdoms Linnaeus only named two kingdoms (plants & animals)(plants & animals)
Modern Evolutionary ClassificationModern Evolutionary Classification
– Problems with traditional classification• Dolphins fish or mammals• Barnacle, limpet, crab
– Because of convergent evolution, sometimes organisms that are very different evolve similar body structures
Evolutionary ClassificationEvolutionary Classification
• Darwin’s theory of evolution changed the entire way that biologist thought about classification
• scientists began to understand that organisms share certain traits because of their evolutionary history
• Biologists group organisms into categories that represent lines of evolutionary descent, not just physical similarities.