Biology 2900 Evolution and Systematics

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Biology 2900Evolution and Systematics
Cladistics applications Review
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USES OF PHYLOGENIES

• To resolve the Tree of Life
• Determine origins of lineages
• Reveal origins of novelties
• Establish basis for classification
• Explain distributional patterns
• Explain coevolutionary patterns
• Character transformations, losses
• Determine patterns of change in traits
• Directions rates of change in traits
• Reveal trends e.g., convergence

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Example 1 Resolve the Tree of Life
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Example 2 Bear names and classification
Polar bear U. maritimus
Brown bear Ursus arctos
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Distribution of brown bear samples from Alaska
and Siberia
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1) Why is the taxon Ursus arctos
paraphyletic? 2) What are some taxonomic and
classificatory solutions?
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Does chameleon distribution reflect land-mass
splitting or dispersal? (text Fig. 14.13)
Seychelles
Mascarene Islands
Example 3 Distributional patterns of chameleons
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Land-mass splitting and chameleon relationships
are discordant Chameleon biogeography is
explained best by dispersal
Splitting pattern of land masses
Relationships among chameleons
(text Fig. 14.13)
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Character mapping General term for
placing characters on independently obtained
phylogeny
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Fungi (left) ants (right) Symbiotic forms in
bold (text Fig. 13.11)
Example 4 Evolution of ant-fungus symbiosis
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Example 5 distributional patterns
and behavioural evolution of Australasian wolf
spiders
AUSTRALIA/NEW ZEALAND
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T suspended tubular hideout W web-building B-P
permanent burrow
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Example 6 Median eye of ostracods
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8 photoreceptive 4 lens cells per unit (like
other arthropods)
6 photoreceptive 2 lens cells per unit
The compound eye of myodocopid ostracods evolved
independently