modern classification sorts organisms into groups shows relationships among them
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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 - PowerPoint PPT PresentationTRANSCRIPT
Modern Classificationsorts organisms into groups
shows relationships among them
PhylogenySystematics
Cladistics
Classification and DiversityClassification
- 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
LinnaeusCarolus Linnaeus – Swedish botanist, 1700s used physical appearance and structure
Binomial Nomenclature - two names for each Genus: group to which it belongs species: 1-2 word description
Ex. Homo sapiens
7 taxa: from broad to specific Kingdom – Phylum – Class – Order - Family – Genus – Species
Evidence for ClassificationMany 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
Fossils Embryo Development
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 namingSpecies – 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
Phylogeny – evolution history
Simplest relationships make the most likely phylogenetic trees
Phylogeny -compares structureHomologous – similar structure, with adaptations
- shows common ancestry
Analogous structures– Evolved in similar environments– NOT shared ancestry
CladisticsTries to show evolutionary relationships based on physical traits shared by different groups of organisms
CladogramsMore 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
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
• Ribosomal RNA
– Have shown that fungi are more closely related to humans than to green plants
Student Mushroom Tulip
Common ancestorFigure 15.9B
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
DNA – Compare genes and DNA sequences
- many similar sequences = closely related
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
More shared genes = closer relationship
Human Chimpanzee Gorilla Orangutan
Common ancestorFigure 15.9C
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
Molecular Clocks• Some regions of DNA or proteins
– Change at a fairly consistent rate
– Can date evolutionary events
Five- Kingdoms System
• Prokaryotes are in one Kingdom – Monera• Eukaryotes are grouped in separate kingdoms
– Animals, Plants, Fungi, Protists
(Classification is a work in progress!)
Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings
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