1. In island radiations we often see the following pattern: similar forms found in different species living in similar habitats on different islands. This pattern raises the question: did the form...

1. In island radiations we often see the following pattern: similar forms found in different species living in similar habitats on different islands. This pattern raises the question: did the form evolve once on a single island in a single species and then spread to multiple islands by dispersal (let’s call this the “dispersal model”)? Or did a single species first disperse to different islands, then ecologically adapt to the many different environments on each (let’s call this the “convergence model”)? A phylogeny can help us identify which of these processes is at play. Considering the three traits shown on this tree, which model appears to have more support: the dispersal model or the convergence model? Explain how you arrived at this conclusion.

Extracted text: Habit Oshrub tree Leaf margin unlobed Capitula O homogamous slightly lobed distinctly lobed partially heterogamous O fully heterogamous S. villosa S. stewartii S. atractyloides S. affinis S. cordata S. microcephala S. crockeri S. aspera S. retroflexa S. helleri S. pedunculata S. baurii S. gordilloi S. divisa S. incisa h d. d a ·bcghD bc g g dghkI aef k k 0.6 0.5 0.4 0.3 0.2 0.1 O Ma 0000 00 00●00 00000 D00