What are the different techniques used by scientists to determine the timing of flowers’ evolution?

Flowers May Be More Ancient Than Dinosaurs, Say Scientists

Flowers may look delicate – but flowering plants, what scientists call angiosperms, are one of the most successful evolutionary organisms on the planet. Including more than 350,000 known species, they dominate the ecological system, shape food webs and play a vital role in oxygen production. Plus, many of them are valuable commercial crops – think of roses, grains and tomatoes.

Jurassic or Cretaceous?

The timing of flowers’ evolution is still a matter of debate between scientists, but most scientists are in one of two camps: Jurassic or Cretaceous.

Analyses using molecular data (DNA or protein sequences) suggest flowers could be much older than the fossil record shows – a Jurassic (145 million years ago) or even Triassic origin (201 million years ago).

Scientists also examine fossil plants and observe the gradual changes in structures such as leaves, flowers and seeds over time. Comparing their anatomy allows researchers to identify similarities and differences between extinct and still-living species, or species in different clades.

Deciphering the Past by Molecular Data

One technique scientists use to determine the timing of evolutionary events is the “molecular clock”. This concept originated from the understanding that genetic mutations tend to accumulate at a constant rate across both time and species. The rate of mutation can be likened to the steady ticking of a clock.

Variations in gene sequences between different species can help tell scientists when they diverged from a common ancestor. To construct a molecular clock, researchers analyse gene segments that have been conserved throughout a species’ evolution.

Mathematical Approach Can Also Help

There is also a mathematical approach to estimating the age of angiosperms – for instance, using the Bayesian Brownian Bridge (BBB) method. This statistical model is a scientific formula that uses the distribution of fossils through time to estimate the age of a group.

By using the BBB method, an international research team found that the origin of angiosperms supports a pre-Cretaceous hypothesis. This means flowers may have evolved alongside, and outlived, the dinosaurs.

Understanding the origins of angiosperms gives scientists valuable insights into the intricate web of life on our planet. It can also guide efforts in agriculture and conservation. So, the next time you marvel at a vibrant flower or enjoy a juicy fruit, remember that the story of angiosperms is a tale of resilience, adaptation and beauty – much of which is still waiting to be discovered.