Scientists have uncovered an unexpected feature of cacti
Cacti are commonly thought of as slow and almost unchanging plants. But a new study has shown that their "leisurely" appearance hides an unexpected ability - they can evolve rapidly.
Scientists at the University of Reading have studied more than 750 species of cacti and found that the speed at which new species emerge is not related to flower size or pollinators, as previously thought.
The key factor turned out to be how quickly the shape of the flower changes.
"People think of cacti as slow plants, but our study shows that they are one of the fastest evolving groups," says paper author Jamie Thompson.
Details
In their analysis, the researchers compared flowers ranging from tiny (about 2mm) to giant (up to 37cm). However, size had almost no effect on the emergence of new species.
But the dependence on the rate of change turned out to be direct:
What matters is not how big or complex a flower is, but how quickly it changes.
It is those species whose flower shape changes faster that are more likely to give rise to new species.
Why it matters
The results challenge ideas going back to the time of Charles Darwin that flower and pollination characteristics play a key role in the emergence of new species.
It's also important for conservation. Currently, about a third of cactus species are threatened with extinction.
Scientists believe that when assessing the risk, it is necessary to take into account not only the appearance of plants, but also the speed of their evolution.
Background
The cactus family has about 1,850 species and has been actively evolving over the last 20-35 million years, spreading across the Americas.
This shows that even harsh desert ecosystems remain dynamic and constantly changing.
Cacti can grow slowly, yet evolve rapidly. And it's not the size of the flower that plays a decisive role in this, but the speed of change.
Source
Thestudy is published in Biology Letters, University of Reading