Transcript Tracing Phylogeny

Systematics
The study of
biological
diversity in an
evolutionary
context
Systematic
Tools

Molecular Comparisons
– usually (rRNA or
mtDNA)
 DNA-DNA
Hybridization
 Restriction maps
 DNA Sequence
analysis
Taxonomy
The science
concerned with
naming and
classifying the
diverse forms of life
Taxonomic Groups
Domain
Kingdom
Phylum (Division)
Class
Order
Family
Genus
Species
Domains (Table 27.2)
Bacteria Archaea Eukarya
Cell type
Prokaryote
Prokaryote
Eukaryote
Introns
Absent
Present
Present
RNA Poly
One
Several
Several
P. S.
Formylmethionine
Methionine
Methionine
Binomial Nomenclature
Panthera leo
(African Lion)
Binomial Nomenclature
Ardea herodias
(Great Blue Heron)
Classification and Phylogeny
Phylogenetic Groupings

Monophyletic
– ancestor and all its descendants
Phylogenetic Groupings

Paraphyletic
– ancestor with some but not all its
descendants
Phylogenetic Groupings

Polyphyletic
– two different ancestors
Phylogenetic Groupings
Similarities

Homology
– likeness attributed
to shared
ancestry
Similarities

Analogy
– likeness due to
similar ecological
roles and natural
selection due to
convergent
evolution
Molecular Homoplasy

Analogous species that have similar
DNA sequences that evolved
independently in two species
Ontogeny Recapitulates
Phylogeny (Ernst Haeckel)
Ontogeny – individual
development
 Recapitulates –
repeats
 Phylogeny –
evolutionary descent

The Science of Systematics

Phenetics
– based on a number of similarities and
differences
– does not take into account homology
or analogy
– all groupings
Classical Evolutionary
Systematics

George Gaylord Simpson
The Science of Phylogenetic
Systematics

Classical Evolutionary Systematics
– most commonly used up until recently
– based on shared homologous
structures
– takes into account the amount of
adaptive evolutionary change
(novelties)
– Monophyletic and paraphyletic
groupings
The Science of Systematics

Cladistics
(Phylogenetic
Systematics)
– based on shared
homologous
structures
– only monophyletic
groupings
Will Hennig
The Science of Phylogenetic
Systematics

Cladistic Assumptions
1. Monophyletic
2. Descent follows a bifurcating
pattern
3. Changes in characteristics occur
in lineages over time
Cladistics


Shared primitive
characters
– Outgroupings
– Plesiomorphies
Ancestral
characteristics
Shared derived
characters
– Synapomorphies
Phylograms
Ultrametric
Trees
Cladistics
Cladistics
Cladistics
Pitfalls
Reptiles?????
Molecular
Clock
Tree of Life
Phylogenetic Fuse