Botany’s answer to Darwin’s finches shows evolution in real time
A new study reveals how a remarkable group of plants on the Galápagos Islands developed their diverse leaf shapes – offering unique insight into evolution at the genetic level.
The Galápagos Islands hold an iconic place in the history of evolutionary biology. When Charles Darwin landed there in 1835 during his voyage on the HMS Beagle, he collected birds that he later brought back to England. Darwin believed he had gathered sparrows, woodpeckers, finches – and a single tit. But he soon learned that all of them were, in fact, closely related finches. Their different appearances were the result of beaks adapted to different diets.
This provides a clear example of parallel evolution: nature arriving at the same solution multiple times, but through different genetic pathways.
These finches became a key argument for Darwin’s theory of evolution by natural selection – that species can change in ways shaped by the environments they inhabit.
Michael D. Martin. Photo: NTNU
“More than 150 years after Darwin’s work on the Galápagos transformed our understanding of life on Earth, these islands continue to reveal new biology,” says Professor Michael D. Martin at the NTNU University Museum.
He is part of a large international team of researchers from the Royal Botanic Gardens, Kew; the University of California, Davis; the University of Copenhagen; the Charles Darwin Foundation, Galápagos; the University of Georgia, Athens; the University of British Columbia; and several other institutions. Together, they have studied evolution in the plant group Scalesia, also known as the Galápagos giant daisies. The research was recently published in Nature Communications.
Unusually rapid evolution
“Just like Darwin’s famous finches, these plants evolved rapidly after arriving on the Galápagos from mainland South America,” explains Vanessa Bieker, a researcher at the Royal Botanic Gardens, Kew, and the first author of the new publication.
The genus Scalesia is evolutionarily young. All species living today emerged within the last one million years. Yet they have managed to adapt to the wide range of environments found across the islands – from dense, humid highland forests to dry, open lowlands.
Serrated leaves of Scalesia affinis (radiate-headed scalesia). Photo: Michael Martin, NTNU University Museum
“The appearance of different species varies dramatically, from low shrubs to tall trees. Most striking are the leaves, which range from large and entire to small and deeply lobed,” says Martin.
Lobed leaves, with their sometimes complex and serrated edges, are thought to help the plants survive in hot, dry environments by reducing water loss and dissipating heat. Until now, however, researchers have not understood how this important adaptation evolved at the genetic level in these plants.
Multiple evolutionary paths to the same leaf shape
By analyzing the complete genomes of all known Scalesia species, the researchers discovered that lobed leaves evolved several times – each time in different parts of the Scalesia family tree.
Close-up of serrated leaves of Scalesia affinis (radiate-headed scalesia). Photo: Michael Martin, NTNU University Museum
New species may be in the process of forming. Many Scalesia populations may represent distinct evolutionary lineages that have not yet been formally described.
“Even more surprising was that each time this trait evolved, it did so through different genes – even though all of them belong to the same biological system controlling leaf development,” says Bieker.
“This provides a clear example of parallel evolution: nature arriving at the same solution multiple times, but through different genetic pathways. Instead of being controlled by a single ‘master gene’, evolution appears to draw on an entire network of interacting genes, tweaking different components to produce similar outcomes.”
This gives researchers important insight into how complex traits can arise again and again in nature.
Evolution still in progress
In addition to uncovering how these plants evolved, the researchers found that evolution is still ongoing.
Herbarium sheet with Scalesia incisa collected by Charles Darwin during the voyage of the Beagle in the Galápagos Islands from 1831-1836. Photo: GBIF, Cambridge University Herbarium (CGE) collection, CC BY-NC 4.0
“Populations within the same species show large genetic differences and have been isolated from one another for long periods. This means new species may be in the process of forming. Many Scalesia populations may represent distinct evolutionary lineages that have not yet been formally described,” says Martin.
The researchers therefore argue that each isolated population should be treated as its own conservation unit – a shift that could influence how the unique nature of the Galápagos is protected in the future. The study also offers a rare, detailed look at the process by which one species rapidly diversifies into many different forms.
“Our findings highlight the flexibility and creativity of evolution,” says Bieker.
She added that Darwin also collected many plants on the Galápagos. Seventy‑eight of them were later used to describe species entirely new to science – including four species of Scalesia.
Reference:
Bieker, V.C., Li, S., Cerca, J. et al. The genomic basis of adaptive leaf variation in the Galápagos giant daisies. Nat Commun (2026). https://doi.org/10.1038/s41467-026-71865-3
