Putting the algal tree of life to useEvolutionary dynamics of ecological niches, physiology

and species’ diagnostic traits

Heroen Verbruggen School of Botany, University of Melbourne

Algal Diversity

• architecture

• functional traits

• life history

• physiology

Algal Tree of Life• systematics: species delimitation

and higher-level relationships

• phylogenies in evolutionary enquiry

• endosymbiosis events: patchwork of genes → accumulation of genomic features

• examples of phylogenetics applied in evolutionary questions

Talk contents

Systematics

Thermal Niche

Trace Elements

Thermal niche

van den Hoek. 1982. Biol. J. Linn. Soc. 18: 81-144 — Cambridge et al. 1984. Helgol. Meeresunt. 38: 349-363 — Eggert. 2012. In: Wiencke, C., Bischof, K. [Eds.] Seaweed Biology

Thermal niche

Map: T. Schils

Species diversity map

Codium

How does the thermal niche evolve?

How fast?

Which direction?

Pulsed or gradual?

Effect on biodiversity?

Are there covariates?

Exploration

Which direction?

Codium Dictyotales

Tropics

Temperate0.011

0.027Tropics

Temperate0.028

0.032

Are there covariates?sheltered exposed

HalimedaMarcelino et al. 2014. submitted

Pulsed or gradual?

Dictyota

Thermal niche & diversification

DictyotaTyberghein et al. unpublished

Thermal niche evolution• thermal niches evolve over geological timescales

• microhabitat preferences affect evolvability

• diversification relates to SST and its evolvability

• results are taxon-specific

• scale up to bigger datasets: more species

• harder questions: adaptation, interactions, timescales

Talk contents

Systematics

Thermal Niche

Trace Elements

Trace element utilization

Raven. 1999. Photosynthesis Research 60: 111-149

Thylakoid membrane with photosystems

Trace element utilization

Quigg et al. 2003. Nature 425: 291-294

Hypothesis

ExplorationCya

Eug

Cha

Stra

Din

Din

Gla

HapCry

Rho

Chltime(Ga) 00.511.5

Feutilization

low high

Hypothesis ⇒ Model

Cya

EugCha

Stra

Din

GlaHapCry

Rho

Chl

Cya

Eug

Cha

Stra

Din

Din

Gla

HapCry

Rho

Chl

Host phylogeny Plastid phylogeny

Parfrey, L.W., Grant, J., et al. 2010. Syst. Biol. 59: 518-533 — Baurain, D., Brinkmann, H., et al. 2010. Mol. Biol. Evol. 27: 1698-1709.

Results for Fe/P ratioPulsed Gradual

0 10.25

Nuclear Tree0.40 Plastid Tree

Relative rates

σ 2ENDO = 73.5

σ 2OTHER = 447.3

Nuclear tree

p = 0.09Relative rates

σ 2ENDO = 103.2

σ 2OTHER = 382.9

Plastid tree

Simulation study5.05!7.55!3.64!7.94!3.54!4.23!2.42!5.92!6.55!9.78!3.93!4.95!5.17!5.14!6.04!5.10!5.53!4.29!3.76!5.05!2.98!9.28!3.49!2.07!5.67!7.11!6.07!6.05!7.95!3.36!3.95!0.12!3.80!4.02!5.63!4.57!5.22!7.35!5.55

non-ES rate ES rate

1

100

0.01

1

100

0.01

Power analysis

Trace element utilization

• results are inconclusive

• support for existing hypotheses is limited

• power to detect differential evolution of continuous traits is low

• limited effect of increase in taxon sampling

• metalloproteomics approaches

Talk contents

Systematics

Thermal Niche

Trace Elements

Role of ToL in Systematics

Simulation: extrapolate what we know about trait evolution

A

B

C

Problem: Cryptic Diversity

Zuccarello, G.C., West, J.A. 2003. J. Phycol. 39: 948-959. — Photo: J. West

How big is the problem?

Pseudochlorodesmis

Verbruggen, H. et al. 2009. J. Phycol. 45: 726-731 — Photo: H. Verbruggen

Is it more of a problem in simple organisms?

Complexity and diagnosability

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

Simulation: extrapolate what we know about trait evolution

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Complexity and diagnosability

20 characters theoretical maximum = 1,048,576

10 characters theoretical maximum = 1,024

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

• higher complexity ⇒ more unique morphologies • # unique morphologies << # species in clade

total # species

# un

ique

mor

phol

ogie

s

Habitat selection

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

A

B

C

D

E

➙ 1

➙ 3

➙ 5

➙ 7

➙ 9

Habitat selection

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

Plasticity

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

A

B

C

D

E

➙ 1

➙ 3

➙ 5

➙ 7

➙ 9

Plasticity

Verbruggen, H. 2014. J. Phycol. 50: 26-31.

Morphological evolution

• # unique morphologies << number of species

• null hypothesis: cryptic diversity abounds

• fundamental inability to distinguish some species (possibly many) morphologically

• problem more pronounced in simple organisms

• plasticity blurs species boundaries

Talk contents

Systematics

Thermal Niche

Trace Elements

Conclusions• test evolutionary hypotheses

• insights from parameters

• measure uncertainty

• simulation to study behavior of methods

• simulation to improve expectations

• perspectives: genome dynamics, life histories, etc.

Verbruggen, Marcelino, Costa (2014) Evolutionary dynamics of algal traits and diversity. Perspectives in Phycology 1: in press [available from www.phycoweb.net]

Acknowledgements

• Collectors

• Collaborators

• Previous workers