Most complete tree of life

A five-year effort to reconstruct the evolutionary relationships among all of Earth’s green plants has resulted in the most complete “tree of life” of any group of living things on the planet. The team has revealed that the group traditionally thought of as “plants” is really four separate lineages or “kingdoms,” with one group – fungi – being more related to animals than to plants. The team has overturned the traditional belief that the so-called “land-plant invasion” was led by seawater plants. Instead, the research team has found that primitive fresh-water plants provided the ancestral stock from which all green plants now on land are descended and that this ancestor spawned every green plant now alive on earth.

The team of 200 scientists from 12 countries are all part of the “Green Plant Phylogeny Research Coordination Group,” funded in the United States by the National Science Foundation, the U.S. Department of Agriculture, and the U.S. Department of Energy. “Better understanding this ‘tree of life’will allow scientists to better predict the biological properties of plants,” said Brent D. Mishler, a co-principal investigator for the team and Professor of Integrative Biology at the University of California, Berkeley, who spoke at a media briefing. “When you find a new plant, the first thing you want to know is how it is related to other plants. This is very impor-tant in predicting its traits. Green plant species are of particular economic value because they provide most of our food, shelter and medicines.”

The team has clarified the plant “kingdoms” and their relationships to animals. There are five main trunks, or lineages, of complex, "nucleated" organisms on the Earth's genealogical tree, four of which are classified as plants. They include the green plants, the brown plants, the red plants, the fungi, and the animals. The green plant lineage is the largest of the four plant groups, comprising about 500,000 species, including all of the Earth's land plants (trees, shrubs, grasses, flowers, ferns, mosses) and some of the aquatic plants, such as green algae.