Phylogenetics and Phylogenetics and the Tree of Lifethe Tree of Life
Level 1 Biological DiversityLevel 1 Biological Diversity
Jim ProvanJim Provan
Campbell: Chapters 25 & 26Campbell: Chapters 25 & 26
Key events in the evolution of Key events in the evolution of lifelife
The major lineages of lifeThe major lineages of lifeLinnaeusLinnaeus originally originally divided all known forms divided all known forms of life betweenof life between animalanimal andand plantplant kingdomskingdomsThe discovery of bacteria The discovery of bacteria did not change thisdid not change this::
BacteriaBacteria classed with classed with plantsplantsFungiFungi classed with plantsclassed with plantsUnicellular creatures:Unicellular creatures:
– Ingest food: animals Ingest food: animals (protozoa)(protozoa)
– Photosynthetic: plantsPhotosynthetic: plants
Taxonomy employs a Taxonomy employs a hierarchical system of hierarchical system of
classificationclassificationDeveloped by LinnaeusDeveloped by LinnaeusHas two main features:Has two main features:
BinomialBinomial (latin name) unique to each species(latin name) unique to each species– First word isFirst word is genusgenus; second word is; second word is specific epithetspecific epithet– Each genus can include many related speciesEach genus can include many related species– Defines organism and removes ambiguityDefines organism and removes ambiguity
A hierarchical “filing system”:A hierarchical “filing system”:– Begins with binomial nomenclatureBegins with binomial nomenclature– Progresses upwards, becoming more inclusiveProgresses upwards, becoming more inclusive– Range ofRange of taxonomic levelstaxonomic levels
Hierarchical classificationHierarchical classificationDomain
EukaryaEukarya
Classification and phylogenyClassification and phylogeny
Determining monophyletic taxaDetermining monophyletic taxa
In order to truly reflect evolutionary history, all In order to truly reflect evolutionary history, all taxonomic levels should betaxonomic levels should be monophyleticmonophyleticNot always the case:Not always the case:
Kingdom Plantae isKingdom Plantae is polyphyleticpolyphyleticClass Reptilia isClass Reptilia is paraphyleticparaphyletic, since it does not include , since it does not include AvesAves
Discriminating between Discriminating between homology and analogyhomology and analogy
HomologyHomology: : likeness due likeness due to shared ancestryto shared ancestryAnalogyAnalogy: : likeness due tolikeness due to convergent evolutionconvergent evolution::
Forelimbs of mammals Forelimbs of mammals are homologousare homologousWings of birds and bats Wings of birds and bats are analogous since they are analogous since they originated independently originated independently from forelimbs of different from forelimbs of different ancestorsancestors
Phylogenetic systematicsPhylogenetic systematics
The traditional five-kingdom The traditional five-kingdom systemsystem
Proposed byProposed by Robert Robert WhittakerWhittaker in 1969in 1969Recognises Recognises prokaryotesprokaryotes and and eukaryoteseukaryotesAll prokaryotes placed in All prokaryotes placed in KingdomKingdom MoneraMoneraRecognises three Recognises three kingdoms of kingdoms of multicellular eukaryotesmulticellular eukaryotesProtistsProtists are largely are largely unicellular eukaryotesunicellular eukaryotes
Domain Eukarya (Eukaryotes)
Alternative classification Alternative classification systemssystems
Monera Protista Plantae Fungi Animalia
Plantae Fungi AnimaliaC
hrom
ista
Prot
ista
Arc
haez
oa
ArchaeaBacteria
Plantae Fungi Animalia
Rho
doph
ya
Stra
men
opila
Arc
haez
oa
DomainArchaea
DomainBacteria
Eugl
enoz
oa
Alv
eola
ta
Plants - where do they (and we) Plants - where do they (and we) fit in?fit in?
BacteriaBacteria ArchaeaArchaea EukaryaEukaryaAnimals
FungiFungiPlantsPlants
