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Modern Classification sorts organisms into groups shows relationships among them. Phylogeny Systematics Cladistics. Classification and Diversity. Classification - tries to organize all living things into groups - show how they evolved from earlier life forms
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Modern Classificationsorts organisms into groupsshows relationships among them Phylogeny Systematics Cladistics
Classification and Diversity Classification - tries to organize all living things into groups - show how they evolved from earlier life forms - show relationships to other present forms - changes with new information Early Systems Aristotle - by environment: land, water, air John Ray (1600s) - in related groups - short description for each species
Linnaeus Carolus Linnaeus – Swedish botanist, 1700s used physical appearance and structure • 7 taxa: from broad to specific • Kingdom – Phylum – Class – Order • - Family – Genus – Species Binomial Nomenclature - two names for each Genus: group to which it belongs species: 1-2 word description Ex. Homo sapiens
Evidence for Classification Many forms: - physical appearance and structure (morphology) - other present organisms - fossils - molecules, especially DNA, RNA, proteins - embryology patterns Various organizing diagrams
Evidence for Evolutionary Relationships • Physical appearance and structure • Resemblance to other organisms
Phylogeny and Systematics Taxonomy – sort and name organisms Phylogeny - Evolutionary history of a group of organisms - shows common ancestry Systematics - combines taxonomy with evolution - organized way to study diversity and relationships
Taxonomy – sorting and naming Species – individual type of organism Genus – group of related species Scientific Name = Genus & species Family – related genera Order – related families Class – related orders Phylum – related classes Kingdom – related phyla Domain – Three Domain System
Simplest relationships make the most likely phylogenetic trees
Phylogeny -compares structure Homologous – similar structure, with adaptations - shows common ancestry
Analogous structures • Evolved in similar environments • NOT shared ancestry
Cladistics Tries to show evolutionary relationships based on physical traits shared by different groups of organisms
Cladograms More shared traits = more closely related Derived character – more recent branch from evolutionary line Primitive character - older, shared by more groups
Molecular Systematics • Compares molecules to find relationships
Student Mushroom Tulip Common ancestor Figure 15.9B • Ribosomal RNA • Have shown that fungi are more closely related to humans than to green plants
DNA – Compare genes and DNA sequences • - many similar sequences = closely related
Human Chimpanzee Gorilla Orangutan Common ancestor Figure 15.9C • More shared genes = closer relationship
Molecular Clocks • Some regions of DNA or proteins • Change at a fairly consistent rate • Can date evolutionary events
Five- Kingdoms System (Classification is a work in progress!) • Prokaryotes are in one Kingdom – Monera • Eukaryotes are grouped in separate kingdoms • Animals, Plants, Fungi, Protists
Six-Kingdom System • Bacteria are divided into two kingdoms, based on their chemical nature
Three Domain System • One domain for all eukaryotes • One domain for each of the two kinds of bacteria