Phylogenetics

Chapter 26

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Ontogeny recapitulates Phylogeny

Ontogeny – development from embryo to adult

Phylogeny – evolutionary history of a species or group of species

Taxonomy – ordered classification of organisms based on a set of characteristics

Systematics – classification of organisms by their evolutionary relationships Basis of phylogeny

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Binomial Nomenclature

Each species is assigned a 2-word name Developed by C. Linnaeus

First word is the genus & second word is species Example: Canis familiaris Escherichia Coli (E. Coli)

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Phylogenetic Trees

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Homologous Structures

How do we determine phylogenetic relationships? Morphological similarities due to common ancestry Insert diagram of homologous structures

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Analogous Structures

Similarities that are NOT due to common ancestry

Indicate similar solutions to a common problem

Usually due to convergent evolution When 2 organisms develop similarities as they adapted

to similar environmental challenges

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Molecular Systematics

DNA or other molecular characteristics are used to determine evolutionary relationships

More similar DNA sequences, closer their evolutionary relationship

Ribosomal RNA is used for investigating distant relationships (hundreds of millions of years ago)

Mitochondrial DNA evolves rapidly Used for investigating recent evolutionary trends

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Cladograms

Visually depicts a phylogenetic tree between groups

Highlights the patterns of shared characteristics

Homologous characteristics or molecular similarities

Clade Group of species that include an ancestral species and

all of its descendents

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7 Levels of Order

Kingdom

Phylum

Class

Order

Family

Genus

Species

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Kingdoms or Domains

Old taxonomy

Kingdoms – **Monera – Bacteria Protista Fungi Animalia Plantae

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Domains (Kingdoms)

In this model, K. Monera is split into 2 kingdoms

K. Monera is separated into: Domain Archaebacteria Domain Eubacteria

Other Domain: Eukarya Consists of K. Fungi, K. Plantae, K. Animalia

Also, much of K. Protista has been classified into 1 of the other 3 kingdoms What are the other 3 kingdoms called?

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Prokaryotic Domains

1. Archea Extremeophiles Halophiles Thermophiles Methanogens

2. Bacteria (Eubacteria) Proteobacteria Gram-Positive Chlamydia Cyanobacteria Spirochetes

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Domain Eukarya

Eukaryotes

Superkingdom - incorporates 4 of the kingdoms from the kingdom model Protista Fungi Plantae Animalia

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3 Domains Compared

Feature Archae Bacteria Eukarya

Membrane-bound organelles

Peptidoglycan in Cell Walls

Introns

Antibiotic Sensitivity

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Questions

In the Kingdom classification, how many kingdoms are there?

What are the names of the Kingdoms?

In the Domain classification, how many Domains are there and what are they?