Vascular plants are the most conspicuous organisms on Earth, accounting for some 97 % of our planet's standing biomass. The nearly 300,000 extant vascular plant species exhibit tremendous morphological and ecological diversity. Along with the 20,000 or more species of bryophytes, algae, lichens, and cyanobacteria that also live on land, they fuel a complex terrestrial ecosystem containing animals, fungi, protozoans, and bacteria. The richness of terrestrial life has evolved during the last 10 % of Earth history; there is no evidence for non-microbial land plants or animals in rocks older than the mid-Ordovician.