Flowering plants aren’t just pretty to look at; if they had never evolved, the human species probably wouldn’t have either. The brains of our primate ancestors grew large on a diet of fruit and flowers provided by a group of plants known as ‘angiosperms’. But over 140 million years ago there was no such thing as a flower – plants such as conifers and ferns used other methods other than flowers to reproduce. A few million years after the last dinosaur walked the planet, flowering plants took over conifers as the most common type of tree. Today there are thought to be between 250 000 and 400 000 species of flowering plant. What caused them to be so successful? According to a botanist from the University of Tasmania, it could have something to do with the plant’s pipes. In nature, it’s a race to make as many babies as quickly as you can. This takes resources, like food and water, so it makes sense that organisms that can make the best use of the materials on hand will do a better job of reproducing. To get energy, plants need water and sunlight. Bigger leaves allow plants to use more sunlight, but they can also provide more surface area for water to escape from the plant. Researchers wondered if angiosperms were better suited to getting both more water and more sunlight than other plants. To test this, they investigated the density of the plumbing called ‘xylem’ in the leaves of over 500 types of plant. By comparing angiosperms that had evolved very little with those that had changed a great deal, they discovered that flowering plants developed a better way to carry water up to their leaves when they first evolved. Learning how flowering plants grow and reproduce most efficiently is vital for future ecologists and farmers. After all, we rely heavily on the fruits of their labours to survive.
However, Paleontologists from Bradford University now think that the evidence points to humans evolving away from a tree-living fruit diet to a ground living nuts and tubers diet.