Biology2: Phylogeny

The Study of biological diversity in an evolutionary context.

• - Molecular Comparisons
• - usually (rRNA or mtDNA)
• - DNA-DNA Hybridization
• - restriction maps (restriction enzymes)
• - DNA Sequence analysis

The science concerned with naming and classifying the divers forms of life.

The number can always change but for now there are 8: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

He was the first to suggest a 3-domain system for Taxonomy.

• - Bacteria: Prokaryote
• - Archaea: Prokaryote
• - Eukarya: Eukaryote

• - Archaea are prokaryotic cells but they make DNA and proteins more like Eukaryotes.
• - Archaea have about 44% different DNA than Bacteria and Eukarya.

• The two name identification for individual organisims on the species level.
• Ex:
• Genus Species
• Panthera Leo
• (African Lion)

• Monophyletic: Ancestor and ALL descendants.
• Paraphyletic: Ancestor with some of its descendants.
• Polyphyletic: Somewhat Random. Descendant from 2 ancestors.

Monophyletic

Paraphyletic

Polyphyletic

• What organisms have the same structures for different functions or purposes.
• - likeness attributed to shared ancestry

• When organisms have different evolutionary backgrounds but function the same.
• - likeness due to similar ecological roles and natural selection due to convergent evolution
• - not due to similar ancestry.

- Analogoeus species that have similar DNA sequences that evolved independantly in 2 species.

• 1. Embryos Leave Evidence for Evolutionary Background
• - Ontogeny- individual development
• - Recapitulates- repeats
• - Phylogeny- evolutionary descent
• 2. Nope, its all Bullshit!
• 3. Ernst Haeckel

• A type of Systematics:
• - based on a number of similarities and differences
• - not taking into account homology or analogy
• - using all phylogenetic groupings.

• - George Gaylord Simpson
• - 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.

• A phylogenetic Systematics:
• - based on shared homologous structures
• - only monophyletic groupings
• - began by Will Henrig?

• 1. Must use Monophyletic Groupings
• 2. Descent must follow a Biforcating Pattern
• 3. Changes in characteristics occur in lineages over time

• - shared derived characteristics
• - A shared taxa from a common ancestor with the same taxa.

• - Ancesteral characteristics
• - Shared primitive characteristics
• - Outgroupings

Phylogram

Ultrametric Tree

When there are multiple possiblities the simplest is probably correct.

Maximum Liklihood

A pitfall