20 Phylogeny

Phylogeny - evolutionary history of a species or group systematics classifies organisms and determines evolutionary relationships Taxonomy is the ordered division and naming of organisms 2

Kingdom: Animalia Domain: Bacteria Domain: Archaea Domain: Eukarya Figure 20.3 Species: Panthera pardus Genus: Panthera Family: Felidae Order: Carnivora Class: Mammalia Figure 20.3 Linnaean classification Phylum: Chordata Kingdom: Animalia Domain: Bacteria Domain: Archaea Domain: Eukarya 3

Linking Classification and Phylogeny Systematists depict evolutionary relationships in branching phylogenetic trees 4

Cladistics Cladistics classifies organisms by common descent A clade is a group of species that includes an ancestral species and all its descendants 5

Order Family Genus Species Felidae Panthera pardus (leopard) Panthera Figure 20.4 Order Family Genus Species Felidae Panthera pardus (leopard) Panthera Taxidea taxus (American badger) Taxidea Carnivora Mustelidae Lutra lutra (European otter) Lutra 1 Figure 20.4 The connection between classification and phylogeny Canis latrans (coyote) Canidae Canis 2 Canis lupus (gray wolf) 6

Each branch point (node) represents the divergence of two taxa Sister taxa (Sister clades) are groups that share an immediate common ancestor 7

where lineages diverge Taxon A Figure 20.5 Branch point: where lineages diverge Taxon A 3 Taxon B Sister taxa 4 Taxon C 2 Taxon D 5 Taxon E ANCESTRAL LINEAGE 1 Taxon F Figure 20.5 How to read a phylogenetic tree Basal taxon Taxon G This branch point represents the common ancestor of taxa A−G. This branch point forms a polytomy: an unresolved pattern of divergence. 8

Figure 20.10a A valid clade is monophyletic, signifying that it consists of the ancestor species and all its descendants (a) Monophyletic group (clade) A 1 B C D Figure 20.10a Monophyletic, paraphyletic, and polyphyletic groups (part 1: monophyletic) E F G 9

Figure 20.10b A paraphyletic grouping consists of an ancestral species and some, but not all, of the descendants (b) Paraphyletic group A B C D Figure 20.10b Monophyletic, paraphyletic, and polyphyletic groups (part 2: paraphyletic) E F G 10

Figure 20.10c A polyphyletic grouping consists of various taxa with different ancestors (c) Polyphyletic group A B C D Figure 20.10c Monophyletic, paraphyletic, and polyphyletic groups (part 3: polyphyletic) E F G 11

A shared ancestral character is a character that originated in an ancestor of the taxon A shared derived character is an evolutionary novelty unique to a particular clade 12

Lancelet (outgroup) Lamprey Bass Vertebral column Frog Hinged jaws Figure 20.11b Lancelet (outgroup) Lamprey Bass Vertebral column Frog Hinged jaws Turtle Four walking legs Figure 20.11b Constructing a phylogenetic tree (part 2: phylogenetic tree) Amnion Leopard Hair (b) Phylogenetic tree 13

Euglenozoans Forams Diatoms Ciliates Domain Eukarya Red algae Figure 20.20 Euglenozoans Forams Diatoms Ciliates Red algae Domain Eukarya Green algae Land plants Amoebas Fungi Animals Nanoarchaeotes Archaea Domain Methanogens COMMON ANCESTOR OF ALL LIFE Thermophiles Figure 20.20 The three domains of life Proteobacteria (Mitochondria)* Chlamydias Spirochetes Domain Bacteria Gram-positive bacteria Cyanobacteria (Chloroplasts)* 14

No limbs Eastern glass lizard Monitor lizard Iguanas ANCESTRAL Snakes Figure 20.2 No limbs Eastern glass lizard Monitor lizard Iguanas ANCESTRAL LIZARD (with limbs) Snakes Figure 20.2 Convergent evolution of limbless bodies No limbs Geckos 15

Figure 20.1 Figure 20.1 What kind of organism is this? 16