Grasses, which make up 20% of the Earth’s surface, are only 65 million years old and were thought to be 55 million years old until grass fossils were found in dinosaur feces. Grasses are important for food, industry, and grassland, with grains providing half of human calories and 70% of plant crops.
Herbs might be thought to be among the simplest of plants and to have evolved around the same time as the first vascular (water-carrying tissues) land plants, about 410 million years ago. However, grasses – the Poaceae family in flowering plants – only evolved much more recently, during the Late Cretaceous, just 65 million years ago, just before the extinction that wiped out the dinosaurs. Until recently, grasses were thought to be only 55 million years old, until grass fossils were discovered in fossilized dinosaur feces, known as coprolites. Some of these fossils were ancient ancestors of today’s rice and bamboo.
More specifically, paleontologists have found grass phytoliths in the coprolites. Phytoliths (meaning “plant stone”) are tiny beads of silicon found in many plants, but especially herbs. Phytoliths add structural integrity to the plant, as well as making it grainier and therefore less palatable to animals. The inability to process phytoliths is one reason humans cannot consume herbs. Grass-consuming mammals have special stomachs that let the brew ferment before it is fully digested.
Because grasses are so abundant today, covering 20 percent of the earth’s surface, filling areas called grasslands, it’s hard to imagine a time when it didn’t exist. Although land plants have been around for 410 million years, grasses are only 65 million years old, less than 16% of the total. Before there was grass, its niche was filled by smaller vascular plants that lacked the characteristic blades or siliceous tissue of grasses. Because grass is unique to the Cenozoic (recent) period, it is sometimes referred to as the “Age of Grasses.” The Cenozoic was a period of relatively low temperatures and constant glacial cycles, which contributed to making the world’s vegetation less luxuriant. Prior to this, a typical scenario on Earth would be the Earth covered in forests, often extending from pole to pole.
Today, humans are intimately dependent on grasses for food, industry and grassland. Grains, such as wheat, rice and corn, provide half of all human calories, and 70% of all plant crops are grasses. The grass sugar cane is used to make sugar. Bamboo is commonly used for construction in Asia, while other grasses are made into pulp for paper production.
Protect your devices with Threat Protection by NordVPN
