Even Charles Darwin was stumped by this: the origin and extensive diversification of flowering plant species (known as angiosperms) over 130 million years ago. Flowering plants dominate terrestrial environments and provide most of our food, such as rice, wheat, and maize. They are now a necessary part of nearly every ecosystem – without flowering plants, our world literally would not look the same. Knowing how flowering plants evolved and why they are such a diverse group of species gives us one piece of the puzzle as to how our present world came to be, and how some groups of organisms contribute so much more to biodiversity than other groups.
In the current issue of Science (Amborella Genome Project, 2013, Science 342), members of the Amborella Genome Project sought to find the origin of flowering plants and why they rushed onto the scene, diversifying into over 350,000 species. They did this by sequencing the genome (i.e. the biological equivalent [DNA] of a software program) of Amborella trichopoda, a species at the base of the flowering plant family tree – this allowed the scientists to determine what all flowering plants have in common. In the case of flowering plants, it appears as though they originated from a whole-genome duplication event, which effectively doubles the information contained in the organism’s DNA. This results in a lot of redundancy in the system – since with two copies of everything, losing one copy of something is not as catastrophic as if there was only one copy. In flowering plants, some of this extra information was co-opted for the production of flowers, plant-animal interactions, and environmental stress responses. And likely because of all this extra information, flowering plants were able to diversify rapidly to live in diverse habitats around the world.
So now we are much closer to solving the puzzle that Darwin struggled with – it only took modern biological techniques, massive computing power, and a large team of scientists. This is but one part of the story of the tree of life, but we are learning to tell it, one species at a time.
Stay safe and stay informed,