Abstract Detail

Biogeography

Clark, John R. [1].

What came first, the island or the species? Exploring the role of key innovations and ecological opportunity in insular lineage diversification.

A central question in island biogeography is why certain lineages are better adapted to island dispersal and diversification than others. Several hypotheses have been proposed for these lineages, including “key innovations” – physical or physiological traits that increase the probability of dispersal, colonization and lineage divergence. Alternatively, newly formed areas with unrealized ecological opportunities (e.g., the formation of volcanic, oceanic islands) may stimulate an increase in lineage divergence rates. Weighing the relative influences of factors that affect lineage divergence rates is now possible as a result of advancements in methodology. The flowering plant family Gesneriaceae (African violets and their relatives) provides an opportunity to examine island colonization in relation to disparities in diversification rates as affected by key innovations and/or ecological opportunity: although gesneriads are found distributed throughout all of the world’s tropical forests, only one genus, Cyrtandra J.R. & G.Forster, has colonized the remote Pacific Islands. The monophyletic Pacific clade of Cyrtandra evolved rapidly within the last 20 MYBP suggesting that a “key innovation” occurred in this clade. Alternatively, or perhaps in conjunction with key innovation, new, unexploited habitat among volcanic Pacific islands facilitated this rapid diversification. The current study builds on the extensive sampling and molecular phylogenetic/ancestral range history hypothesis for Cyrtandra to further interpret how both morphological traits and ecological opportunities have lead to the largest diversification of a single gesneriad genus. Recently developed methods for analyzing lineage diversification rates, coupled with phylogenetic dating, ancestral area and ancestral state reconstruction are here used to interpret correlations in diversification rates in the context of both key innovations and geological events. Future studies and methods application are considered and discussed.

Broader Impacts:

1 - Marie Selby Botanical Gardens, Gesneriad Research Center, 811 S. Palm Ave., Sarasota, Florida, 34236, USA

Keywords:
ancestral range reconstruction
dispersal-mediated allopatry
diversification rates
phylogenetics
island biogeography
Gesneriaceae
Cyrtandra
key innovation
ecological opportunity.

Presentation Type: Oral Paper:Papers for Topics
Session: 3
Location: 551A/Convention Center
Date: Monday, August 2nd, 2010
Time: 11:30 AM
Number: 3014
Abstract ID:578