This is The Guardian.

The evolutionary innovations that wait millions of years to come good by Andreas Wagner.

What are the most successful organisms on the planet?

Some people might think of apex predators like lions and great white sharks,

for others, insects or bacteria might come to mind.

But few would mention a family of plants that we see around us every day.

Grasses. Grasses meet at least two criteria for spectacular success.

The first is abundance. Grasses cover the North American prairies, the African savannas,

and the Eurasian steps which span 5,000 miles from the Caucasus to the Pacific Ocean.

A second criterion is the number and diversity of species.

Since the time grasses originated, they have evolved into more than 10,000 species

within astonishing variety of forms. From centimed to high tufts of hair grass adapted to the

freezing cold of Antarctica, to the towering grasses of northern India that can hide entire

elephant heads, and to Asian bamboo forests, with trees that grow up to 30 meters tall.

But grasses weren't always so spectacularly successful.

For tens of millions of years, most of their evolutionary history, in fact,

grasses barely eaked out of living. Their origin dates back to the age of dinosaurs more than 65

million years ago. But for many millions of years, the fossil record suggests they were not abundant.

In fact, it wasn't until less than 25 million years ago that they became the dominant species

that we recognize today. Why did grasses have to wait 40 million years for their proverbial spot

in the sun? This mystery deepens once you know that early on, evolution endowed grasses

with multiple survival-enhancing innovations. Among them are chemical defences like

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