What Did The First Flower Look Like? New Study Gives Scientists Insight
With around 300,000 species, flowers are the most diverse group of plants on the planet– a whopping nine out of 10 plants are flowering plants. So it’s hard to imagine a time that there was just one. But botanists have long known that all flowers alive today are “monophyletic,” meaning they evolved from a single common ancestor. What this flower would have looked like when it first appeared (sometime around 140 million years ago!) has long been a mystery– or “a big biologic enigma,” as botany experts put it.
Until now, that is.
Scientists involved in the “eFLOWER project” worked for more than six years to amass the largest database of the traits of modern flowers, including their sexual organs and the layouts of their petals and leaves. The team combined that information with a DNA-based family tree to test millions of configurations of how flowers may have changed throughout time, in order to determine the most likely structure and shape of the earliest flower. Their findings were recently published in the journal Nature Communications.
So what did the first flower look like? Though it would be natural to expect that a prehistoric flower would be unlike any bloom you’ve ever seen, it turns out that it closely resembles a modern water lily or magnolia.
It’s no surprise that the ancient flower looks like a fairly close relative of flowers of today, says study co-author Jürg Schönenberger, PhD, deputy head of the Department of Botany and Biodiversity Research at the University of Vienna. “It is made up of the same basic organs and has the same basic organization,” he points out. Similarly, like many flowers today, researchers discovered that the ancestral flower was bisexual, with both female and male parts– information that cleared up a long-standing ambiguity.
Despite its likeness to modern flowers and to certain ones in particular, Schönenberger is careful not to point out a particular lineage for the ancestral flower. “Even if some of today’s flowers are similar, there are none that match it exactly,” he says. Indeed, the study– which also reconstructed what the two largest groups of flowering plants looked like at all the key divergences in the evolutionary tree– makes clear that starting from the ancestral flower, different lineages have explored different evolutionary pathways. (Editor’s note: The two largest groups of flowering plants are the monocots (which include orchids and lilies) and eudicots (which include poppies, roses, and sunflowers).)
“These results call into question much of what has been thought and taught previously about floral evolution,” says Schönenberger.
Another key takeaway for researchers– in fact, what Schönenberger deems the most important finding of the study– is that the original bloom was arranged in multiple “whorls,” or concentric circles of petal-like organs, of sets of three. Since it has long been assumed that the ancestral flower had all organs arranged in a spiral pattern– rather than whorls– “these results call into question much of what has been thought and taught previously about floral evolution,” says Schönenberger.
While much has been learned from this study, there’s still more to discover– so the eFlower project will continue. Going forward, the team plans to include more species and additional floral traits, and possibly even fossil flowers, to reconstruct a more-detailed model of the ancestral bloom and its early descendants. In the meanwhile, let’s count ourselves lucky that the original flower from 140 million years ago bloomed at all– how it came to be in the first place is another evolutionary mystery still waiting to be solved.
