Date post: | 20-Jun-2015 |
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But was it adaptive?Drift and adaptation in the radiation of the white proteas
Adaptive radiations• “the most common
syndrome in the origin of taxa” (Schluter 2000, p. 1)
Adaptive radiations• Adaptive (Schluter 2000; Gavrilets & Losos
2009)
• Divergent selection – among species
• Stabilizing selection – within species
Adaptive radiations• Adaptive (Schluter 2000; Gavrilets & Losos
2009)
• Divergent selection – among species
• Stabilizing selection – within species
• Explosive (Gavrilets & Vose 2005; Puebla et al. 2008)
Protea
Valente et al. (2009)
5 – 18 mya
Protea
Valente et al. (2009)
White protea0.34 – 1.2 mya
White protea
White proteaWinter rainfall Summer rainfall
White protea
Was it adaptive?
Was it adaptive?• Is variation correlated
with environment?
Sampling•35 populations•11-40 adults per population
Was it adaptive?• Is variation correlated
with environment? YES!•Is it genetic?
Sampling•35 populations•11-40 adults per population• 8 maternal lines per
population• Up to 15 seeds per
maternal line
Was it adaptive?• Is variation correlated
with environment? YES!•Is it genetic? YES!
Was it adaptive?• Is variation correlated
with environment? YES!•Is it genetic? YES!•Is it related to performance?
Logistic regression• “Selection” gradients
on garden survivorship• Convert logistic
regression coefficients to selection gradients
Kirstenbosch
Jonaskop
SLA -0.024 -0.017LWR -0.058 0.024Leaf area 0.389 -0.007Stomatal density
-0.061 -0.006
Growth rate 0.097 0.180
“Selection” gradients
Kirstenbosch
Jonaskop
SLA -0.024 -0.017LWR -0.058 0.024Leaf area 0.389 -0.007Stomatal density
-0.061 -0.006
Growth rate 0.097 0.180
“Selection” gradients
Large leaves favored in warm, moist garden
Kirstenbosch
Jonaskop
SLA -0.024 -0.017LWR -0.058 0.024Leaf area 0.389 -0.007Stomatal density
-0.061 -0.006
Growth rate 0.097 0.180
“Selection” gradients
Thick leaves favored in cold, dry garden
Was it adaptive?•Yes
Was it adaptive?•YesWas it explosive?
Microsatellites•36 populations•20 individuals per population•10 loci
FSC = among pops within speciesFCT = among species
FS
C
FCT
FSC = among pops within speciesFCT = among species
FS
C
FCT~50% of history associated with species divergence
Was it adaptive?•YesWas it explosive?•No
Structural equation model•Integrated response
Trait-environment associations•Among populations•Among species
Trait-environment associations•Among populations•Among speciesDo populations and species differ in the same ways?
Association differs among species•56 of 60 signs differ (P < 0.001)
Association differs among species•56 of 60 signs differ (P < 0.001)
Association differs among species•56 of 60 signs differ (P < 0.001)
Population divergence – adaptive
Population divergence – adaptiveSpeciation – non-adaptive?
Adaptive radiations• Not uniform• Adaptation and drift
Acknowledgments
Collaborators• John Silander• Guy Midgley
(SANBI)• Tony Rebelo
(SANBI)Post-doc• Jane CarlsonGraduate student• Rachel PrunierField assistants• Christopher Adams• Ann Marie Gawel
Undergraduates• Charles Berdan• David Fryxell• Sirenga Iyer• Susan Kim• Bronwen TombFacilities• Kirstenbosch National
Botanic GardenFunding• NSF
Acknowledgments
Collaborators• John Silander• Guy Midgley
(SANBI)• Tony Rebelo
(SANBI)Post-doc• Jane CarlsonGraduate student• Rachel PrunierField assistants• Christopher Adams• Ann Marie Gawel
Undergraduates• Charles Berdan• David Fryxell• Sirenga Iyer• Susan Kim• Bronwen TombFacilities• Kirstenbosch National
Botanic GardenFunding• NSF
Thank you!