CPB : David Collar

Identifying ecological constraint on morph and function using phylogenies. 

2007 CPB grad, losos post doc, now postdoc w Rita.

Indep origin of ‘bass’ cranial morph.  Also unique patterns-  stonefish.  Phylo comparative methods to address why and how.  Three types of factors on morphology:  ecological, time!, intrinsic (genetic, behavior) constraints. 


I. determinants of morph diversification.

  1. Complex traits.

  2. Diversification rate vary by habitat?  (Dragon lizards- diverse morph, diverse habitat).  Reconstruct history of habitat use (4 types), (assign discrete traits) then stoch character maps to reconstruct  (paint) tree.  Looks at PC trait by habitat before correcting.  Now adds trait model:   


Then use painted trees (500) for character evo models: Brownie.  (Explains w example sim).  4 rate, also looks at several 3 and 2 & 1 rate models.  Compare by AIC choose 4 rate for first three PC.

So which have faster rates? Ground dwelling.  Bc less constrained than climber morphs?

II.  Complex biomechanics in fish suction feeding.   

(Videos of suction feeding) “in the first attak the bluegill aims poorly, probably bc there is a sheet of laaser light shining in its face.”  Hehe. 

Looks at force of flow at mouth, but also reach of flow-  a tradeoff!  Smaller gape, stronger lever/muscle, increase protrusion/ram speed.  Gape has tradeoff in reach and force, other traits don’t.  Can compensate?  Centrachids ex. 

Phylo indep contrasts on performance & diet.  @cboettig:  Did you do any model choice (phylo signal) first? 

So does this mitigate a trade-off?  Compare to simple system (simulated where only gape size determines force – strong tradeoff).   Yes, complexity mitigates, may promote morph, funct & eco diversity! 

  Also uses posterior dist of trees.