1. Accelerated diversification is related to life history and locomotion in a hyperdiverse lineage of microbial eukaryotes (Diatoms, Bacillariophyta)
- Author
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Jeremy M. Beaulieu, Andrew J. Alverson, and Teofil Nakov
- Subjects
0301 basic medicine ,life history ,diversification ,Physiology ,Plant Science ,Oogamy ,Life history theory ,anisogamy ,03 medical and health sciences ,Phylogenetics ,Clade ,Phylogeny ,Diatoms ,oogamy ,biology ,Phylogenetic tree ,Full Paper ,Ecology ,Fossils ,Research ,fungi ,Biodiversity ,15. Life on land ,Full Papers ,biology.organism_classification ,Biological Evolution ,030104 developmental biology ,Diatom ,Anisogamy ,motility ,Species richness - Abstract
Summary Patterns of species richness are commonly linked to life history strategies. In diatoms, an exceptionally diverse lineage of photosynthetic heterokonts important for global photosynthesis and burial of atmospheric carbon, lineages with different locomotory and reproductive traits differ dramatically in species richness, but any potential association between life history strategy and diversification has not been tested in a phylogenetic framework.We constructed a time‐calibrated, 11‐gene, 1151‐taxon phylogeny of diatoms – the most inclusive diatom species tree to date. We used this phylogeny, together with a comprehensive inventory of first–last occurrences of Cenozoic fossil diatoms, to estimate ranges of expected species richness, diversification and its variation through time and across lineages.Diversification rates varied with life history traits. Although anisogamous lineages diversified faster than oogamous ones, this increase was restricted to a nested clade with active motility in the vegetative cells.We propose that the evolution of motility in vegetative cells, following an earlier transition from oogamy to anisogamy, facilitated outcrossing and improved utilization of habitat complexity, ultimately leading to enhanced opportunity for adaptive divergence across a variety of novel habitats. Together, these contributed to a species radiation that gave rise to the majority of present‐day diatom diversity.
- Published
- 2018