Tree of life for flowering plants reveals relationships among major groupsNovember 27, 2007AUSTIN, Texas-The evolutionary Tree of Life for flowering plants has been revealed using the largest collection of genomic data of these plants to date, report scientists from The University of Texas at Austin and University of Florida. The scientists, publishing two papers in Proceedings of the National Academy of Sciences this week online, found that the two largest groups of flowering plants, monocots (grasses and their relatives) and eudicots (including sunflowers and tomatoes), are more closely related to each other than to any of the other major lineages. The analyses also confirmed that a unique species of plant called Amborella, found only on the Pacific island of New Caledonia, represents the earliest diverging lineage of flowering plants.
Robert Jansen, professor of integrative biology at The University of Texas at Austin, said the work sets the stage for all future comparative studies of flowering plants. "If you are interested in understanding the evolution of flowering plants, you can't do that unless you understand their relationships," said Jansen. The University of Florida team, led by Doug and Pam Soltis, also showed that the major diversification of flowering plants, so stunning that the researchers are calling it the "Big Bang," took place in the comparatively short period of less than five million years. This resulted in all five major lineages of flowering plants present today. "Flowering plants today comprise around 400,000 species," said Pam Soltis, curator at the university's Florida Museum of Natural History. "To think that the burst that gave rise to almost all of these plants occurred in less than five million years is pretty amazing-especially when you consider that flowering plants as a group have been around for at least 130 million years." The details of the flowering plants' rapid diversification have remained a mystery since Charles Darwin first suggested their evolutionary history is an "abominable mystery." "One of the reasons why it has been hard to understand evolutionary relationships among the major groups of flowering plants is because they diversified over such a short time frame," said Jansen. But by analyzing DNA sequences from completely sequenced chloroplast genomes, the scientists brought some clarity to the evolutionary picture. Jansen and his colleagues at The University of Texas at Austin analyzed DNA sequences of 81 genes from the chloroplast genome of 64 species of plants, while the Florida researchers analyzed 61 genes from 45 species. The two groups also performed a combined analysis, which produced evolutionary trees that included all of the major groups of flowering plants. As for the diversification's cause, it remains mysterious, Pam and Doug Soltis said. It's possible it was spurred by some major climatic event. It's also possible that a new evolutionary trait -a more efficient water-conducting cell that transfers water up plant stems-proved so effective that it spurred massive plant growth. This cell type is not present in the first three flowering plant lineages, said Doug Soltis, professor of botany at Florida. University of Texas at Austin | |||||||||||||||||||||
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Related Flowering Plants News Articles Microbes, by latitudes and altitudes, shed new light on life's diversity Microbial biologists, including the University of Oregon's Jessica L. Green, may not have Jimmy Buffett's music from 1977 in mind, but they are changing attitudes about evolutionary diversity on Earth, from oceanic latitudes to mountainous altitudes. Saving our bees Most of the world's plant species rely on animals to transfer their pollen to other plants. The undisputed queen of these animal pollinators is the bee, made up of about 30,000 species worldwide, whose daily flights aid in the reproduction of more than half of the world's flowering plants. UT Knoxville professor finds unexpected key to flowering plants' diversity What began with an off-the-cuff curiosity eventually led Joe Williams to hang from the limbs of a tree 80 feet above the soil of northeastern Australia. Duckweed genome sequencing has global implications Three plant biologists at Rutgers' Waksman Institute of Microbiology are obsessed with duckweed, a tiny aquatic plant with an unassuming name. Now they have convinced the federal government to focus its attention on duckweed's tremendous potential for cleaning up pollution, combating global warming and feeding the world. Newly Compiled Online Bee Checklist Allows Biologists To Link Important Information About All Bee Species n time for National Pollinator Week, June 22 through June 28, biologists have completed an online effort to compile a world checklist of bees. They have identified nearly 19,500 bee species worldwide, about 2,000 more than previously estimated. When Plants Think Alike Biologists have discovered that a fundamental building block in the cells of flowering plants evolved independently, yet almost identically, on a separate branch of the evolutionary tree--in an ancient plant group called lycophytes that originated at least 420 million years ago. Flowers' fragrance diminished by air pollution, University of Virginia study indicates Air pollution from power plants and automobiles is destroying the fragrance of flowers and thereby inhibiting the ability of pollinating insects to follow scent trails to their source, a new University of Virginia study indicates. A common genetic mechanism discovered in nitrogen-fixing plants Some soil microorganisms are capable of forging associations with plant roots in the form of symbioses. Certain of these relationships play a highly important ecological and agronomic role. Insect attack may have finished off dinosaurs Asteroid impacts or massive volcanic flows might have occurred around the time dinosaurs became extinct, but a new book argues that the mightiest creatures the world has ever known may have been brought down by a tiny, much less dramatic force - biting, disease-carrying insects. UF botanists: Flowering plants evolved very quickly into 5 groups University of Florida and University of Texas at Austin scientists have shed light on what Charles Darwin called the "abominable mystery" of early plant evolution. More Flowering Plants News Articles |
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