Evolution and Phylogeny

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Evolution and Phylogeny

• General Mycology
• PlP 421/521

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From Whittaker, 1969
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Thallophyta (Fitzpatrick 1930)

• Myxothallophyta (slime thallophytes)
• Acrasieae
• Labyrinthuleae
• Myxomycetes (Mycetozoa, slime moulds)
• Euthallophyta
• Bacteria (Schizomycetes, fission fungi)
• Fungi (Eumycetes)
• Phycomycetes
• Ascomycetes
• Basidiomycetes
• Fungi Imperfecti
• Lichens
• Algae

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Science 163 150-160 (1969)
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Relationship between fungi and animals

• Ultrastructural evidence
• Fungi and animals have flattened mitochondrial
  cristae lower fungi and protozoa have tubular
  mitochondrial cristae
• Biochemical evidence
• Fungi and animals synthesize lysine by the alpha
  amino adipic acid (AAA) pathway lower fungi,
  green algae and vascular plants synthesize lysine
  by the diaminopimelic acid (DAP) pathyway
• Fungi and animals produce chitin lower fungi
  have cellulose in their walls, like plants

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Science 260 340-342 (1993)
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Wainright et al. 1993
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alpha-tubulin, beta-tubulin, actin, elongation
factor 1-alpha
Science 290 972-977 (2000)
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Science 290 973. 2000
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From Baldauf (2003) Science 300 1703--1706
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Science vol. 289
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Increasing diversity of angiosperms, mammals,
birds mass extinction at end of period
Gymnosperms dominant, evolution of angiosperms
first birds
Gymnosperms become dominant, first dinosaurs,
first mammals
Extensive forests of early vascular plants, esp.
lycopsids, sphenopsids and ferns
Origin of insects, ferns, seed plants
Earliest terrestrial vascular plants
Diversification of invertebrates
marine animals diversify first appearance of
most animal phyla diverse algae
Modified from Blackwell, 2001
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Glomalean fungi from the Ordovician

• Redecker et al (2000). Science 289 1920-21
• Fossil-bearing rocks from a roadcut near Madison,
  Wisconsin
• From mid-Ordovician dolomite deposited 460-455
  mya
• Consists of branching, nonseptate hyphae and
  terminal spores not associated with plants

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Increasing diversity of angiosperms, mammals,
birds mass extinction at end of period
Gymnosperms dominant, evolution of angiosperms
first birds
Gymnosperms become dominant, first dinosaurs,
first mammals
Extensive forests of early vascular plants, esp.
lycopsids, sphenopsids and ferns
Origin of insects, ferns, seed plants
Earliest terrestrial vascular plants
Diversification of invertebrates
marine animals diversify first appearance of
most animal phyla diverse algae
Modified from Blackwell, 2001
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Rhynie Chert fossil beds

• Rhynie -- village in Scotland
• Chert -- finely crystalline quartz
• Early Devonian, 408-360 million years ago
• Formed when mineral sediments settled on top of
  and compressed organic matter
• Fossils formed through silica replacement of
  organic matter
• Studied using thin sections made through the rock
  

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http//www.scotese.com/newpage3.htm
By the Devonian the early Paleozoic oceans were
closing, forming a "pre-Pangea".  Freshwater fish
were able to migrate from the southern hemisphere
continents to North America and Europe.  Forests
grew for the first time in the equatorial regions
of Arctic Canada.
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Aglaophyton from Rhynie Chert

• Several groups of plants had developed
• These plants were small (lt 0.5 m), and simply
  structured, lacking leaves and roots
• One of the most structurally simple of these
  plants was Aglaophyton

16 cm tall max., stem diam 1.5-6 mm
http//www.xs4all.nl/steurh/engrhyn/erhynie.html
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Glomites rhyniensis

• Fungal hyphae (f) and arbuscules penetrating the
  outer cortex of an Aglaophyton major stem (scale
  bar 100µm)

http//www.abdn.ac.uk/rhynie/fungi.htm
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This is a fungus of the genus Glomites, which was
symbiotic with Aglaophyton, Rhynia and Nothia.
The fungus lived in the dark ring, visible in the
transverse section of the stems. It is related to
Glomus.
http//www.xs4all.nl/steurh/engrhyn/eglomit2.html
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Close-up of preceding slide
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Asteroxylon from Rhynie Chert

• Asteroxylon is another common plant in the fossil
  beds, and is an early member of the club mosses
  the wood vessels of this plant were reinforced by
  annular and spiral thickenings

Up to 50 cm tall, 1 cm diam
http//www.xs4all.nl/steurh/engrhyn/erhynie.html
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Ascocarp in Asteroxylon
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Paleopyrenomycites devonicus, Lower Devonian
ascomycete. From Taylor and Berbee (2006,
Mycologia 98 840)
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Increasing diversity of angiosperms, mammals,
birds mass extinction at end of period
Gymnosperms dominant, evolution of angiosperms
first birds
Gymnosperms become dominant, first dinosaurs,
first mammals
Extensive forests of early vascular plants, esp.
lycopsids, sphenopsids and ferns
Origin of insects, ferns, seed plants
Earliest terrestrial vascular plants
Diversification of invertebrates
marine animals diversify first appearance of
most animal phyla diverse algae
Modified from Blackwell, 2001
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http//www.scotese.com/cretaceo.htm
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Archaeomarasmius Hibbett et al. 1997 Amer. J.
Bot. 84 981-991

• Two mushrooms embedded in New Jersey amber from
  mid- Cretaceous (90-94 mya) morphologically
  similar to extant genus Marasmius
• Three times older than previously reported gilled
  mushroom from Dominican amber (25-30 mya)

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Archaeomarasmius
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• Mycena-like mushroom embedded in Dominican
  Republic amber from Miocene (23.8 to 5.3 mya)

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Protomycena Hibbett et al.1997 Amer. J. Botany
84 981-991
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Aureofungus in Dominican amber
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Dating the evolutionary radiations of the true
fungi

• Mary Berbee and John Taylor (1993 Can. J. Bot
  71 1114-27) used SSU rRNA data calibrated with
  fossil data to show the relative time scale for
  the origin and radiation of the major lineages of
  true fungi
• Based on a rate of 1 nucleotide substitution per
  100 million years
• Berbee Taylor (2001) revised substitution rate
  to 1.26 per million years based on Doolittle et
  al. (1996) divergence of animals and fungi (965
  mya)

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Berbee and Taylor 2001

• Conclusions
• Terrestrial fungi diverged from chytrids 650 mya
  (vs. 550 mya using 1)
• Glomales diverged from Ascomycota and
  Basidiomycota 600 mya (vs. 500 mya)
• Ascomycota split from Basidiomycota 600 mya (vs.
  400 mya)

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Tree showing variation in rates of nucleotide
substitution from Taylor Berbee (2006)
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Taylor and Berbee 2006
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Molecular Evidence for the Early Colonization of
Land by Fungi and Plants Heckman et al. (2001).
Science 293 1129-33

• Molecular clock estimates based on protein
  sequence analyses suggest colonization 600 mya
• Green algae and major lineages of fungi were
  present 1000 mya
• Land plants appeared 700 mya
• First fossil land plants and fungi dated to
  480-460 mya

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Rocks or clocks?

• Conflict between fossil- and molecular-based
  evolutionary time scaleswhy?
• Fossil record is incomplete, difficult to
  interpret, provides a minimum date
• Molecular clock assumes changes in a protein or
  DNA sequence occur linearly with time

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Did fungi facilitate the establishment of
terrestrial life?

• Harsh conditions existed in early terrestrial
  environments
• Water was rare or lacking
• Nutrients were scarce
• No shading, so UV-rays not filtered
• Strong fluctuations in temperature

http//www.humboldt.edu/natmus/lifeThroughTime/Pr
eCam.web/gap26.JPG
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How did colonization of land occur?

• Formation of a lichen symbiosis (Heckman et al.,
  2001) perhaps through endosymbiosis between
  fungus and cyanobacterium (gt 900 mya)
• Long-reaching effects on the environment,
  including global climate change, leading to the
  Neoproterozoic rise in oxygenpossibly leading to
  the Cambrian explosion of animals.

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Fungi?
Science vol. 289
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