ADAPTIVE RADIATIONS: INTERFACING ECOLOGY AND SYSTEMATICS

Lecture Schedule

Lecture

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Introduction to 'Adaptive Radiation'

Concept of Darwin, Osborn, Huxley, Simpson, Lack

Interplay of ecology (adaptation) and systematics (speciation)

Classic examples of 'Adaptive Radiation'

Darwin's finches
Australian marsupials
Hawaiian silverswords
African rift lake cichlids

Recent definitions of 'Adaptive Radiation'

Inherent problems in the study of 'Adaptive Radiations'

Morphological studies

Circularity in studying character evolution in these examples
Widespread convergence in morphological characters under intense selection

Molecular systematic studies

Independence of characters used in phylogenetic reconstruction from that studied in the group undergoing adaptive radiation
Lower homoplasy in molecular data sets

Questions now being asked in molecular systematic studies of adaptive radiations

Do phenotypic similarities among species in a lineage reflect ecological similarities, genealogical relationships, or both?

How reliable a guide to phylogeny are traditional morphological characters?

Have key ecological innovations arisen once or repeatedly within a radiating lineage?

What is the relationship between phylogeny and geographic distribution?

Two plant examples

Brocchinia (Bromeliaceae - pineapple family) from the Guayana Shield

Species composition, distribution, and position in Bromeliaceae

Adaptive radiation in mechanisms of nutrient capture

carnivory
myrmecophytism
Nitrogen fixation
tank epiphytism
non-impounding terrestrial rooting

Phylogeny based on restriction-site mapping & sequencing

Patterns of adaptive radiation and geographic diversification

Hawaiian Lobeliaceae

Genera, distribution, and previous phylogenetic ideas of relationships

Adaptive radiation in habit, fruit, corolla, leaves, and spines

Molecular phylogenetics

all Hawaiian lobelioids
Cyanea in detail

Patterns of adaptive radiation and geographic diversification