The Major Lineages of LifeMolecular data challenges 5 Kingdoms
Monera was too diverse2 distinct lineages of prokaryotes
Protists are still too diversenot yet sorted out
Chapter 26
• Phylogeny is the evolutionary history of a species or group of related species
• The discipline of systematics classifies organisms and determines their evolutionary relationships
• Systematists use fossil, molecular, and genetic data to infer evolutionary relationships
• Taxonomy is the ordered division and naming of organisms
Phylogeny and the Tree of Life
3 Domain system• Domains = “Super” Kingdoms– Bacteria– Archaea• extremophiles = live in extreme environments
– methanogens– halogens– thermophiles
– Eukarya• eukaryotes
– protists– fungi– plants– animals
Archaebacteria&Bacteria
Classification• Old 5 Kingdom system
• Monera, Protists, Plants, Fungi, Animals
• New 3 Domain system– reflects a greater
understanding of evolution & molecular evidence• Prokaryote: Bacteria• Prokaryote: Archaebacteria• Eukaryotes
– Protists– Plants– Fungi– Animals
Prokaryote
Eukaryote
KingdomProtista
KingdomFungi
KingdomPlantae
KingdomAnimalia
KingdomArchaebacteria
KingdomBacteria
Kingdoms
Single-celled ancestor
prokaryotes eukaryotes
Eubacteria Archaebacteria
Protista
multicellularuni- tomulticellular
autotrophs heterotrophs
Plantae
Fungi Animalia
absorptivenutrition
ingestivenutrition
• Organisms classified from most general group, domain, down to most specific, species– domain, kingdom,
phylum, class, order, family, genus, species
Finding commonality in variety
use the mnemonic!
The Evolutionary Perspective
Phylogenies are inferred from morphological and molecular data
• To infer phylogenies, systematists gather information about morphologies, genes, and biochemistry of living organisms
• Organisms with similar morphologies or DNA sequences are likely to be more closely related than organisms with different structures or sequences
Cladistics
• Cladistics groups organisms by common descent• A clade is a group of species that includes an
ancestral species and all its descendants• Clades can be nested in larger clades, but not all
groupings of organisms qualify as clades