Scientists found evolution repeating itself in the Galápagos Islands

More than 150 years after Darwin's finches changed biology, plants in the Galápagos are revealing another evolutionary surprise. Giant daisies repeatedly developed similar heat-tolerant leaf shapes. However, each plant group used a different combination of genes.

Researchers also found big genetic differences among isolated plant populations. This suggests new species might be forming right now.

Evolution on Darwin's Islands

The Galápagos Islands are crucial for studying evolution. Charles Darwin visited in 1835. He collected birds, initially thinking they were different species like sparrows and woodpeckers. Later, scientists realized they were all closely related finches. Their beaks had evolved differently to suit various foods.

These finches became strong evidence for Darwin's theory of natural selection. This theory explains how populations change over time. Individuals with traits that fit their environment are more likely to survive and reproduce.

The birds also show parallel evolution. This is when organisms independently develop similar ways to handle environmental challenges. The genetic changes behind these solutions can be different.

Professor Michael D. Martin from the Norwegian University of Science and Technology (NTNU) University Museum noted that the islands continue to reveal new biology. He is part of a large international research team. This team includes scientists from the Royal Botanic Gardens, Kew, and the University of California, Davis, among others.

The team studied Scalesia, a group of plants known as Galápagos giant daisies. Their findings were published in Nature Communications.

Rapid Evolution in Galápagos Giant Daisies

Vanessa Bieker, a researcher at the Royal Botanic Gardens, Kew, and lead author, explained that these plants evolved quickly. They arrived on the Galápagos from mainland South America.

Scalesia is a young plant group. All current species appeared in the last one million years. Despite this short history, they have adapted to very different island habitats. These include humid highland forests and hot, dry lowlands.

Martin said the species vary greatly in appearance. They range from small shrubs to tall trees. Their leaves are especially striking, from large and whole to small and deeply lobed.

These lobed leaves often have jagged edges. Scientists believe this shape helps plants survive dry, hot conditions. It may limit water loss and release heat better. Until now, the genetic changes causing this adaptation were unclear.

Same Leaf Shape, Different Genes

Researchers analyzed the complete genomes of every known Scalesia species. Their results showed that deeply lobed leaves evolved independently multiple times. This happened in separate branches of the Scalesia family tree.

The findings also suggest new species might be developing now. Many Scalesia populations could be separate evolutionary groups not yet officially recognized.

Bieker found it surprising that each time this trait evolved, it used different genes. All these genes belong to the same biological system that controls leaf development.

This is a clear example of parallel evolution. Nature finds the same solution multiple times but through different genetic paths. Evolution seems to use an entire network of interacting genes, tweaking different parts to get similar results.

Instead of one "master gene" for leaf shape, evolution modifies different parts of a larger genetic network. These separate genetic changes can lead to similar physical traits. This discovery helps scientists understand how complex features can appear repeatedly in unrelated groups or different parts of the same evolutionary family.

New Species May Still Be Forming

Genetic evidence shows the Scalesia evolutionary story is ongoing. Martin noted that populations within the same species show large genetic differences. They have been isolated for long periods. This means new species might be forming. Many Scalesia populations could be distinct evolutionary groups not yet formally described.

Because these isolated populations may be on separate evolutionary paths, researchers suggest each should be managed as its own conservation unit. This could change how conservationists protect the unique plants and ecosystems of the Galápagos.

The study also offers a detailed look at adaptive radiation. This is when one ancestral species quickly develops into many forms suited to different habitats. Bieker said their findings highlight evolution's flexibility and creativity.

Darwin's famous bird collections were not his only important discoveries. He also collected many plants. Seventy-eight of these specimens helped identify species new to science, including four Scalesia species.

Deep Dive & References

• The genomic basis of adaptive leaf variation in the Galápagos giant daisies - Nature Communications, 2026