Abstract Detail



Macroevolution

Rydin, Catarina [1], Thureborn, Olle [2], Blokzijl, Ruben [2], Bolinder, Kristina [1], Wikström, Niklas [3].

The Gnetales – diversity, evolution, form, and function from the Early Cretaceous to the present.

The Gnetales are a small group of gymnosperms with only about a hundred species, but it has nevertheless been intensely studied for many decades. Among foci of interest is their relationship to other seed plants, which has proven difficult to resolve. The group is, however, also interesting in itself with a partly unique form and function, some of which have existed for more than a hundred million years. Furthermore, unexpected, even baffling, scientific results on the group have emerged over and over again. Here I will place some of the discoveries on the Gnetales into context, and describe how they have inspired new projects. One aspect is the understanding of species delimitations, infrageneric relationships, and node ages in the Gnetales, and how understanding of these questions has been affected by phylogenomic investigations. Recent results have overturned those of previous studies, showing that relationships are not always as well resolved as may have been assumed. Another aspect is historical diversity of the group. Gnetalean diversity has apparently fluctuated enormously over geological time, temporally as well as spatially. Through time, sudden and substantial diversity peaks have repeatedly appeared followed by equally sudden diversity collapse. What caused these fluctuations? Preliminary results indicate that the patterns cannot be readily explained by global climate change.


1 - Stockholm University, Department Of Ecology, Environment And Plant Sciences, Stockholm, SE-106 91, Sweden
2 - Stockholm University, Department of Ecology, Environment and Plant Sciences, Stockholm, SE-10691, Sweden
3 - The Royal Academy of Sciences, The Bergius Foundation, Box 50005, Stockholm, SE-10405, Sweden

Keywords:
Gnetales
Ephedra
Gnetum
phylogeny
diversity
Genomics.

Presentation Type: Oral Paper
Number:
Abstract ID:605
Candidate for Awards:None


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