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Classification. Chapter 18. 18-1 Finding Order in Diversity. Living things must be described 1.5 million identified and named species Identification and naming requires organization Classification systems provide this organization Taxonomy – study and assign scientifically accepted names.
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Classification Chapter 18
18-1 Finding Order in Diversity • Living things must be described • 1.5 million identified and named species • Identification and naming requires organization • Classification systems provide this organization • Taxonomy – study and assign scientifically accepted names
18-1 Finding Order in Diversity • Common names vary too much • First attempts described physical characteristics • What are the flaws of this method? • Too long of descriptions • Too many varying observations
18-1 Finding Order in Diversity • Carolus Linnaeus – Father of taxonomy • Developed two word naming system • Always written in italics or underlined • Musca domestica or Musca domestica • First word is the genus, second is the species
18-1 Finding Order in Diversity • Linnaeus’s system consisted of 7 levels • Domain (Largest) • Kingdom • Phylum • Class • Order • Family • Species (Smallest) • Each level is called a taxon (taxa)
18-1 Finding Order in Diversity • Levels up always group more organisms together • Families are grouped into orders • Classes are composed of similar orders • Classes make up phylums
18-2 Modern Evolutionary Classification • Anything above species has been “invented” • How would Linnaeus classify these: • Dolphin • Hermit crab • Sparrow • Cow • Snake • Monkey • Bull Shark
18-2 Modern Evolutionary Classification • Phylogeny – evolutionary relationships among organisms • Used now instead of physical similarities • Evolutionary classification • Species in the same genus are more related than species from another genus
18-2 Modern Evolutionary Classification • All members of genus share a common ancestor • This can be traced through a phylogenic tree • The higher the level, the farther back the ancestor • The more recent the common ancestor, the more related
18-2 Modern Evolutionary Classification • Derived Characters – characters in recent members, but not older members • Result of evolution • Demands force new innovations • Cladogram – using derived characters to determine evolutionary relationships
18-2 Modern Evolutionary Classification • A lot of classification methods are based on appearance • USUALLY, this works…why? • DNA/RNA are similar in related species • These substances are used to make comparisons
18-2 Modern Evolutionary Classification • Evolutionary time can also be measured with DNA • Molecular Clock – use DNA to estimate the length of time species have been evolving • Relies on mutations to repeat • Not just one clock running at a time
18-3 Kingdoms and Domains • Linnaeus started with two kingdoms: • Plantae • Animalia • Scientists realized they needed more • This lead to six kingdoms
18-3 Kingdoms and Domains • Domains – larger and includes the kingdoms • Three kingdoms • Eukarya • Archaea • Archaebacteria • As more discoveries are made, more kingdoms may be made
18-3 Kingdoms and Domains • Domain Bacteria • Unicellular • Prokaryotic • Thick, rigid cell walls around a cell membrane • Cell wall made of peptidoglycan
18-3 Kingdoms and Domains • Domain Archaea • Unicellular • Prokaryotic • Live in extreme environments • Volcanic hot springs • Brine pools • Black mud devoid of oxygen • Lack peptidoglycan
18-3 Kingdoms and Domains • Domain Eukarya • All organisms have a nucleus • Consists of four kingdoms • Protista • Fungi • Plantae • Anamalia
18-3 Kingdoms and Domains • Kingdom Protista • Members have the greatest diversity • Cannot be classified as animals, plants, or fungi • Most single celled organisms • Some are multi-celled algae • Some are photosynthetic
18-3 Kingdoms and Domains • Kingdom Fungi • All are heterotrophs • Feed on dead or decaying organic matter • Most recognizable is the mushroom • Most are multicellular, others (Yeast) are unicellular
18-3 Kingdoms and Domains • Kingdom Plantae • Multicellular • All are photosynthetic autotrophs • Non-mobile
18-3 Kingdoms and Domains • Kingdom Anamalia • Multicellular • Heterotrophs • Mobile • Incredible diversity