Reconstructing the “First Flower”

If there is anything I love as much as birds, butterflies, and bees, it must be flowers. They are everywhere, and they are beautiful. (They are, after all, all about s*x.)

Flowers and flowering plants emerged over 130 millions years ago, during the Cretaceous period. Flowers emerged during the height of dinosaur times, though it isn’t certain how dinosaurs and flowers may have co-evolved. I like to think that dinosaur predation shaped the evolution of flowering plants, but who knows?

One of the great mysteries of evolution is how flowers began. There are so many flowers, with so many diverse features and designs. There must have been a “first flower”, but what was it like?

This summer the eFLOWER project (A framework for understanding the evolution and diversification of flowers) has published a new study that examines this question [2] .This large group of collaborators augment studies of fossil remains and genetic patterns among living plants with a mathematical model of the evolution of flowers.

The study is based on a large dataset of current and fossil flowers, which has over 13,000 traits. Using information about molecular dating and fossils, they examine possible evolutionary tress. Many, many possible trees.

If I understand the method correctly, the analysis generated possible ‘ancestors’ based on the relationships among current and fossil flowers, and then tested candidates by running thousands and millions of simulated generations of evolution. (I don’t fully understand these computations

This is a large computation!

The result of this heroic effort is a reconstruction of the ‘first flower’, which is bisexual and spirally whirled.

herve.sauquet@u-psud.fr, juerg.schoenenberger@univ Image caption 3D model of the ancestral flower reconstructed by the new study, showing multiple whorls of petal-like organs, in sets of threes.

This finding is interesting because the fossil record shows a radiation of different flowers that share some, but not all these features. In other words, the adaptations would amount to losing features of the ancestral flower.

Our results suggest two different evolutionary pathways for the reduction in number of whorls in early angiosperm evolution.

The authors speculate on possible advantages in such reductions, perhaps supporting increased specialization.

This idea would answer questions about how one kind of flower could evolve into a radically different structure (they all evolve from a common ‘super’ flower). Of course, we now want to know how this first flower might have evolved from ‘pre flower’ plants.

I’m sure this will be a controversial conclusion.

For one thing, it’s a gigantic amount of math, based on data and assumptions that must be examined carefully. I imagine that it will be difficult to independently replicate this computation.

This result calls into question generally held theories based on other methods. Reexamination of the earlier work may or may not yield a new consensus.

It will be interesting to see if additional fossil evidence can be found that documents more of the actual flowers of that period.

It is worth pointing out that this study has generated a visualization of a completely hypothetical flower, which has never existed as far as we know. The wonders of computational science!


  1. eFLOWER. eFLOWER: A framework for understanding the evolution and diversification of flowers. 2017, http://eflower.myspecies.info/.
  2. Hervé Sauquet, Maria von Balthazar, Susana Magallón, James A. Doyle, Peter K. Endress, Emily J. Bailes, Erica Barroso de Morais, Kester Bull-Hereñu, Laetitia Carrive, Marion Chartier, Guillaume Chomicki, Mario Coiro, Raphaël Cornette, Juliana H. L. El Ottra, Cyril Epicoco, Charles S. P. Foster, Florian Jabbour, Agathe Haevermans, Thomas Haevermans, Rebeca Hernández, Stefan A. Little, Stefan Löfstrand, Javier A. Luna, Julien Massoni, Sophie Nadot, Susanne Pamperl, Charlotte Prieu, Elisabeth Reyes, Patrícia dos Santos, Kristel M. Schoonderwoerd, Susanne Sontag, Anaëlle Soulebeau, Yannick Staedler, Georg F. Tschan, Amy Wing-Sze Leung, and Jürg Schönenberger, The ancestral flower of angiosperms and its early diversification. Nature Communications, August 1 2017. https://www.nature.com/articles/ncomms16047

 

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