The Galápagos giant daisies did something that sounds impossible: they evolved the same heat-tolerant leaf shape over and over again, but each time used a completely different set of genetic tools. This discovery, published in Nature Communications, adds a new layer to the story of evolution on the islands that helped inspire Charles Darwin’s theory of natural selection.
A plant version of Darwin’s finches
More than 150 years after Darwin studied finches with differently shaped beaks on the Galápagos, a team of researchers turned their attention to a group of plants called Scalesia, or Galápagos giant daisies. These plants arrived from mainland South America and, within the past one million years, exploded into multiple species. Some grow as low shrubs, others as tall trees. Their leaves range from large and smooth to small and serrated. The team found that different lineages of Scalesia independently evolved similar leaf shapes suited to hot, dry conditions. But when they looked at the genes behind those shapes, each lineage had taken a different genetic path to get there. This is a clear example of parallel evolution: the same solution to an environmental problem, built with different genetic blueprints.
Hidden species forming right now
The researchers also discovered major genetic differences among isolated populations of Scalesia living on different islands. These populations are separated by ocean and have not been exchanging genes for a long time. The genetic gaps are so large that the scientists suspect new species may be forming in the present day. Local conservationists on the Galápagos care deeply about these plants because they are found nowhere else on Earth. The daisies are a living laboratory for how life adapts to new environments, and the islands themselves are a UNESCO World Heritage site. The study involved scientists from the Norwegian University of Science and Technology, the Royal Botanic Gardens at Kew, the University of California Davis, the University of Copenhagen, the Charles Darwin Foundation in the Galápagos, and several other institutions.
What this means for understanding evolution
The findings show that evolution does not always follow the same genetic script. When environments demand a certain trait, like leaves that can handle heat and drought, nature can find multiple genetic ways to produce it. This flexibility may help explain how life adapts so quickly to new conditions. The Galápagos giant daisies, like the finches before them, remind us that the islands are still yielding surprises about how species change over time.
