Get access

Variability in thermal and UV-B energy fluxes through time and their influence on plant diversity and speciation

Authors

  • K. J. Willis,

    Corresponding author
    1. Long-term Ecology Laboratory, Biodiversity Research Group, Oxford University Centre for the Environment, Oxford, UK
    2. Department of Biology, University of Bergen, Bergen, Norway
      *Kathy J. Willis, Oxford University Centre for the Environment, South Parks Road, Oxford OX1 3QY, UK. E-mail: kathy.willis@ouce.ox.ac.uk
    Search for more papers by this author
  • K. D. Bennett,

    1. School of Geography, Palaeoecology and Archaeology, Queen’s University, Belfast, UK
    Search for more papers by this author
  • H. J. B. Birks

    1. Department of Biology, University of Bergen, Bergen, Norway
    2. Bjerknes Centre for Climate Research, University of Bergen, Bergen, Norway
    3. Environmental Change Research Centre, University College London, London, UK
    Search for more papers by this author

*Kathy J. Willis, Oxford University Centre for the Environment, South Parks Road, Oxford OX1 3QY, UK. E-mail: kathy.willis@ouce.ox.ac.uk

Abstract

Throughout Earth’s history there have been temporal and spatial variations in the amount of visible and ultraviolet radiation received by ecosystems. This paper examines if temporal changes in these forms of energy receipt could have influenced the tempo and mode of plant diversity and speciation, focusing in particular upon Cenozoic time-scales. Evidence for changing patterns of plant diversity and speciation apparent in various fossil records and molecular phylogenies are considered alongside calculated changes in thermal and solar ultraviolet energy (specifically UV-B) over the past 50 Myr. We suggest that changes in thermal energy influx (amount and variability) affected the tempo of evolution through its influence upon community dynamics (e.g. population size, diversity, turnover, extinctions). It was not only the amount of thermal energy but also variability in its flux that may have influenced these processes, and ultimately the rate of diversification. We suggest that variations in UV-B would have influenced the mode and tempo of speciation through changes to genome stability during intervals of elevated UV-B. We argue, therefore, that although variability in thermal energy and UV-B fluxes through time may lead to the same end-point (changing the rate of diversification), the processes responsible are very different and both need to be considered when linking evolutionary processes to energy flux.

Get access to the full text of this article

Ancillary