Saturday, October 14, 2006
Warsaw, Poland (AFP) - Poland's deputy education minister called for the influential evolutionary theories of Charles Darwin not to be taught in the country's schools, branding them 'lies.'
'The theory of evolution is a lie, an error that we have legalised as a common truth,' Miroslaw Orzechowski, the deputy minister in the country's right-wing coalition government, was quoted as saying by the Gazeta Wyborcza daily Saturday.
Orzechowski said the theory was 'a feeble idea of an aged non-believer,' who had come up with it 'perhaps because he was a vegetarian and lacked fire inside him.'
The evolution theory of the 19th-century British naturalist holds that existing animals and plants are the result of natural selection which eliminated inferior species gradually over time. This conflicts with the 'creationist' theory that God created all life on the planet in a finite number. [Science, Creationism]
Continued at "Keep Darwin's 'lies' out of Polish schools: education official"
Also carried by India's Daily News and Analysis (DNA): "Keep Darwin's 'lies' out of schools: Polish official"
Technorati: warsaw, poland, deputy, education, minister, evolutionary, charles, darwin, country, schools, theory, evolution, error, truth, right-wing, coalition, government, non-believer, british, naturalist, animals, plants, natural selection, species, creationist, god, life, planet, science, creationism, india, daily, news, analysis, dna
Dozens of structures on Saturn's moon Titan that appear to be collapsed slush volcanoes have been revealed by NASA's Cassini spacecraft. The heat and chemicals associated with these possible volcanoes could provide a niche for life on the frigid moon.
Figuring out whether Titan is volcanically active is important because volcanoes could be a source of the methane found in relatively large amounts in the moon's atmosphere. The methane is constantly being broken down by sunlight, so it must be replenished somehow.
In a flyby of the moon on 22 July, radar observations revealed dozens of rounded depressions that look like volcanic structures on Earth called calderas. These depressions form on Earth when the ground collapses after lava has drained out from under it in volcanic eruptions. [Science, Astronomy, Space, Volcano, Evolution, Caldera]
Continued at "Exobiology: Slushy volcanoes might support life on Titan"
Technorati: saturn, moon, titan, slush, volcanoes, nasa, cassini, spacecraft, active, niche, life, frigid, methane, atmosphere, flyby, radar, observations, volcanic, structures, earth, calderas, lava, eruptions, science, astronomy, space, volcano, evolution, caldera, exobiology, life, support, heat, chemicals
From the Discovery Channel: Nine Neolithic-era buildings have been excavated in the Stonehenge world heritage site, according to a report in the journal British Archaeology (paper not yet available online).
The structures, which appear to have been homes, date to 2,600-2,500 B.C. and were contemporary with the earliest stone settings at the site's famous megalith. They are the first house-like structures discovered there.
Julian Thomas (homepage), who worked on the project and is chair of the archaeology department at Manchester University in England, said Stonehenge could have been a key gathering place at the Neolithic era's version of a housing development.
The buildings all had plaster floors and timber frames, and most had a central hearth. Two, including a house possibly inhabited by a community chief or priest, were enclosed by ringed ditches, the largest measuring 131 feet across.
Continued at "Ancient Stonehenge Houses Unearthed"
Technorati: discovery, channel, neolithic, buildings, excavated, stonehenge, world, heritage, site, report, journal, archaeology, structures, stone, megalith, house, julian, thomas, chair, manchester, university, england, era, plaster, timberframes, hearth, chief, priest, ringed, ditches, ancient, unearthed
Keeping track of one set of keys is difficult enough, but imagine having to remember the locations of thousands of sets of keys. Do you use landmarks to remember where you put them? Do you have a mental map of their locations?
Scientists at the University of New Hampshire hope to learn more about memory and its evolution by studying the Clark's nutcracker, a bird with a particularly challenging task: remembering where it buried its supply of food for winter in a 15-mile area. Like many animals preparing for the winter, every fall the Clark's nutcracker spends several weeks gathering food stores. What makes it unique is that it harvests more than 30,000 pine nuts, buries them in up to 5,000 caches, and then relies almost solely on its memory of where those caches are located to survive through winter.
Brett Gibson (homepage), a scientist studying animal behavior, began studying Clark's nutcrackers in graduate school and is continuing his research into memory and the behavior of nutcrackers as an assistant professor in UNH's psychology department.
Continued at "Researcher Uncovering Mysteries Of Memory By Studying Clever Bird"
[Science, Birds, Ornithology, Behaviour]
Technorati: track, location, landmarks, mental, map, university, new hampshire, memory, evolution, clark, nutcracker, buried, food, supply, animals, winter, stores, unique, harvests, pine, nuts, caches, survive, brett, gibson, animal, behavior, research, psychology, unh, department, bird, birds, clever, ornithology, science, behaviour
Friday, October 13, 2006
The latest 'Intelligent Design The Future' Webcast:
On this episode of ID The Future, CSC's Robert Crowther interviews Dr. Jonathan Wells about the continued use of faked drawings as evidence for Darwinian evolution in textbooks in use in schools today.
In his groundbreaking book, 'Icons of Evolution,' (Amazon UK | US) Wells reported on the continued use as an example of evolution of Ernst Haeckel's 19th century drawings of embryos, even though scientists have known for decades that the drawings were fraudulent. While some textbooks have begun to remove the drawings, many textbooks in science classrooms today still have the drawings and teachers still refer to them as proof of Darwin's evolutionary theory.
For more on this read Wells' article 'Setting the Record Straight' from The American Biology Teacher journal."
Listen to "Textbooks Persist in Using Discredited Drawings as Evidence for Evolution" here (and view the archives).
Technorati: intelligent design, future, webcast, csc, jonathan, wells, darwinian, evolution, textbooks, schools, faked, drawings, book, icons, ernst, haeckel, embryos, science, classrooms, teachers, darwin, evolutionary, theory, american, biology, teacher, podcast
The remains of what has been described as a huge lost city may force historians and archaeologists to radically reconsider their view of ancient human history.
Marine scientists say archaeological remains discovered 36 metres (120 feet) underwater in the Gulf of Cambay off the western coast of India could be over 9,000 years old.
The vast city - which is five miles long and two miles wide - is believed to predate the oldest known remains in the subcontinent by more than 5,000 years.
The site was discovered by chance last year by oceanographers from India's National Institute of Ocean Technology conducting a survey of pollution.
Using sidescan sonar - which sends a beam of sound waves down to the bottom of the ocean they identified huge geometrical structures at a depth of 120ft.
Debris recovered from the site - including construction material, pottery, sections of walls, beads, sculpture and human bones and teeth has been carbon dated and found to be nearly 9,500 years old.
..."The whole model of the origins of civilisation will have to be remade from scratch" - Graham Hancock (website). [Science, Archaeology, Anthropology, Oceanography]
Continued at "Lost city 'could rewrite history'"
Technorati: remains, lost city, ancient, human, history, gulf, cambay, coast, india, city, oldest, subcontinent, oceanography, national, institute, ocean, technology, survey, pollution, sidescan, sonar, debris, pottery, walls, beads, sculpture, bones, teeth, origins, civilisation, graham, hancock, science, archaeology, anthropology, rewrite
The smallest collection of genes ever found for a cellular organism comes from tiny symbiotic bacteria that live inside special cells inside a small insect.
The bacteria Carsonella ruddii has the fewest genes of any cell. The bacteria's newly sequenced genome, the complete set of DNA for the organism, is only one-third the size of the previously reported "smallest" cellular genome.
"It's the smallest genome - not by a bit but by a long way," said co-author Nancy A. Moran, UA Regents' Professor of ecology and evolutionary biology and a member of the National Academy of Sciences. "It's very surprising. It's unbelievable, really. We would not have predicted such a small size. It's believed that more genes are required for a cell to work."
Carsonella ruddii has only 159,662 base-pairs of DNA, which translates to only 182 protein-coding genes, reports a team of scientists from The University of Arizona in Tucson and from Japan. [Evolution]
Continued at "Researchers Find Smallest Cellular Genome"
Based on the journal Science paper "The 160-Kilobase Genome of the Bacterial Endosymbiont Carsonella" (Abstract)
Technorati: genes, smallest, cellular, organism, symbiotic, bacteria, cells, small, insect, sequenced, genome, dna, nancy, moran, ecology, evolutionary, biology, national, academy, sciences, cell, base, pairs, university, arizona, tucson, japan, evolution, science, journal
Bloomington, Indiana - Fossilized embryos predating the Cambrian Explosion by 10 million years provide evidence that early animals had already begun to adopt some of the structures and processes seen in today's embryos, say researchers from Indiana University Bloomington and nine other institutions in this week's journal Science. James Hagadorn (homepage) of Amherst College led the multi-disciplinary international collaborative project.
The researchers from the U.S., U.K., China, Sweden, Switzerland and Australia report the first direct evidence that primitive animals 550 million years ago were capable of asynchronous cell division during embryonic development. Asynchronous cell division allows the formation of unique shapes.
'We're learning something about how the very earliest multicellular animals formed embryos and how the embryos developed,' said IU Bloomington biologist Rudolf Raff (homepage), a co-author of the report. 'This gives us an enormous and entirely surprising look at half-a-billion-year-old embryos in the act of cleaving. What a window on the past. We've had no prior idea what they might have done.' [Fossilised, Palaeontology, Paleontology, Biology]
Based on "Cellular and Subcellular Structure of Neoproterozoic Animal Embryos" (Abstract)
Technorati: bloomington, indiana, fossilized, cambrian, explosion, animals, embryos, university, journal, science, amherst, college, international, project, u.s., u.k., china, sweden, switzerland, australia, primitive, asynchronous, cell, division, development, multicellular, biologist, fossils, embryo, animal, complexity, palaeontology, paleontology, cellular, animal, fossilised, biology
Thursday, October 12, 2006
From the University of the Witwatersrand, South Africa: In 1997, Professor Ron Clarke, the renowned Wits University palaeo-anthropologist, made great strides in world palaeontology when he unearthed the first known complete Australopithecus skeleton, known as "Little Foot".
Clarke's historic find is unique because it is the only complete adult Australopithecus skeleton known. However, its importance stems also from the fact that many elements of the find are themselves unique. These are that the discovery has produced the only complete skull of an adult Australopithecus, the only complete hand, complete arm and complete leg. Each one of these reveals a wealth of information about our ancestry, and taken together, provides unparalleled insights into our past.
A long, painstaking process of careful excavation is releasing the skeleton from the concrete-like cave infill, and exciting information about our evolution has been revealed, as the bones are uncovered. Significant parts of "Little Foot" will soon be brought up to the sunlight into a world very different from that which it left, when it fell into the depths of the cavern 3.3 million years ago.
Clarke will highlight the importance of this unique discovery, as well as many others made at Sterkfontein and nearby sites in the past 70 years at the fourth keynote Standard Bank Palaeontological Scientific Trust (PAST), lecture: Out of the Lime Quarry into the Limelight: the Renaissance of Little Foot, to be held at the Wits Great Hall on 24 October 2006, at 6pm. [Continued at the above link] [Anthropology, Paleontology]
See Ron Clarke's "Origin of Species and Evolution" (pdf file)
Technorati: university, witwatersrand, south africa, clarke, wits, palaeontology, australopithecus, skeleton, little foot, unique, complete, discovery, adult, skull, hand, arm, leg, insights, past, excavation, cave, evolution, bones, cavern, sterkfontein, lime, quarry, limelight, origin, species, anthropology, paleontology, science, africa
An interview with NASA's Astrobiology Magazine, Part 4:
Bacteria may not have brains, but they are intelligent. So says Lynn Margulis, co-author of Microcosmos: Four Billion Years of Microbial Evolution (Amazon UK | US). To mark the 20th anniversary of the book's publication, Astrobiology Magazine spoke with Margulis, who laid out the evidence for bacterial intelligence. She also explained why she thinks that, most likely, Mars is a dead world.
Part 1 of the interview via: "Microbial Planet: Symbiogenesis and Lynn Margulis"
Part 2 of the interview via: "We Are All Microbes: Symbiogenesis and Lynn Margulis"
Part 3 of the interview via "Bacteria Don't Have Species: Symbiogenesis and Lynn Margulis"
From Lynn Margulis' homepage:
She argues that inherited variation, significant in evolution, does not come mainly from random mutations. Rather new tissues, organs, and even new species evolve primarily through the long-lasting intimacy of strangers. The fusion of genomes in symbioses followed by natural selection, she suggests, leads to increasingly complex levels of individuality. Dr. Margulis is also acknowledged for her contribution to James E. Lovelock's Gaia concept. Gaia theory posits that the Earth's surface interactions among living beings sediment, air, and water have created a vast self-regulating system.
James Lovelock has recently written "The Revenge of Gaia: Earth's Climate Crisis and the Fate of Humanity" (Currently appearing on the 'Featured Books' page of the Evolution Book Store: UK | US - or go directly to the Amazon book webpage: UK | US - see "The End of Eden: Gaia and James Lovelock" [Science, Change]
Technorati: bacteria, brains, intelligent, lynn, margulis, microcosmos, microbial, evolution, book, astrobiology, magazine, bacterial, intelligence, mars, planet, symbiogenesis, microbes, species, inherited, variation, random mutations, tissues, organs, genomes, symbioses, natural selection, james, lovelock, gaia, earth, self-regulating, system, revenge, climate, change, humanity, crisis, science
An American Scientist book review: Although many of us have gotten used to the idea that our bodies serve the needs of a variety of viruses, bacteria, mites and other parasitic species, it comes as a surprise to most people when they hear that their bodies are also hosting alien parasitic DNA.
Analysis of output from the Human Genome Project makes it clear that just one form of such alien DNA, transposons, makes up about 50 percent of our genome. Every time one of your cells divides, it uses time and energy to replicate this parasitic DNA. There is even evidence that the size of your cells is set to accommodate this extra genetic load. In return, this type of DNA typically does nothing useful for you or any of the other organisms it inhabits.
So why do humans and the vast majority of other species serve as homes for parasitic DNA? This is one of many questions about selfish genetic elements that Austin Burt (homepage) and Robert Trivers (homepage) address in their scholarly, thought-provoking new book, Genes in Conflict: The Biology of Selfish Genetic Elements (Amazon UK | US). As can be gleaned from the title, the authors don't envision an easy alliance between selfish genes and the rest of the genome. [Science, Evolution]
Chapter outlines of Genes in Conflict: The Biology of Selfish Genetic Elements.
Reviewed by Fred Gould (homepage) who is a professor in the departments of entomology and genetics at North Carolina State University.
Technorati: american scientist, book review, viruses, bacteria, mites, parasitic, species, alien, dna, analysis, human, genome, project, transposons, cells, genetic, organisms, humans, selfish, elements, burt, trivers, book, genes, conflict, amazon, us, uk, gould, biology, entomology, genetics, north carolina, state, university, science, evolution
From the National Geographic: Small changes in Earth's orbit and tilt may have regulated the cyclical rise and fall of many prehistoric mammal species, new research suggests.
Earth's orbital patterns are believed to drive long-term climate change.
Over millions of years these climatic shifts may have regularly spawned events that give rise to new mammal species.
They may have also caused the periodic extinctions that doomed other mammal lineages to oblivion, says a team of researchers led by paleontologist Jan van Dam of Utrecht University in the Netherlands.
"The question of climate's role in causing both evolution and extinction has been a big area of contention," said Tony Barnosky (homepage), a paleobiologist at the University of California, Berkeley.
Barnosky is not affiliated with van Dam's new research, which will appear in tomorrow's edition of the journal Nature. [Science, Biology, Paleontology, Palaeontology, Dinosaurs]
Continued at "Earth's "Wobbles" Spurring Cycles of Evolution and Extinction?"
Based on "Long-period astronomical forcing of mammal turnover" (Abstract)
Also see "Your time is up" (Nature Editor's Summary)
Update: See the Washington Post's "When Earth Tilts, Animals Fall Off" (2nd item on page).
Technorati: national geographic, earth, orbit, tilt, prehistoric, mammal, species, research, climate change, extinctions, jan, van dam, utrecht, university, netherlands, climate, evolution, extinction, california, berkeley, journal, nature, cycles, mammal, astronomical, paleontology, palaeontology, science, biology, dinosaurs
A New mammal species - thought to be the first discovered in Europe for more than a century - has been identified by a scientist based at the University of Durham.
The grey mouse, found in Cyprus by Thomas Cucchi, has been confirmed as an entirely new species by genetic tests, overturning the widespread assumption that Europe had no mammals left to be discovered.
Dr Cucchi, who is French, was working on the Mediterranean island studying mouse teeth from the Stone Age period and comparing them with those of four modern mouse species when he came across a variety that seemed to differ from all known European mice.
The species, named Mus cypriacus, or the Cypriot mouse, has a larger head, ears, eyes and teeth than previously known examples. It is described in the journal Zootaxa. [Science, Evolution, Biology, Discovery]
The Zootaxa paper "A new endemic species of the subgenus Mus (Rodentia, Mammalia) on the Island of Cyprus" is listed on this page but the link given for Abstract and excerpt is not working at the time of writing.
Technorati: new, mammal, species, europe, university, durham, grey, mouse, cyprus, thomas, cucchi, genetic, tests, mammals, mediterranean, island, teeth, stone age, period, modern, variety, european, mice, mus, cypriacus, cypriot, head, ears, eyes, journal, zootaxa, endemic, rodentia, mammalia, evolution, science, biology, discovery
Wednesday, October 11, 2006
The two massive horns above Triceratops' eyes grew from tiny stubs that curved backwards, then forwards before settling into a permanent shape in the dinosaur's adulthood, a new study finds.
Triceratops was a ponderous plant-eating creature best known for its great bony head frill and three horns: one above each eye and one above its beaklike mouth. It lived during the late Cretaceous Period, making it among the last dinosaurs to evolve before their demise about 65 million years ago. An adult could grow up to 30 feet long and weighed up to 5 tons.
Researchers John R. 'Jack' Horner* of the University of Montana and Mark Goodwin of the University of California, Berkeley examined the skulls of 10 Triceratops that died at different ages, including recently unearthed baby and juvenile specimens. The baby skull was just over a foot long, while adult skulls were more than six-feet in length." [Science, Evolution, Palaeontology, Paleontology, Fossils, Fossil]
Continued at "Surprising Twists Found in Triceratops Horns"
Based on "Major cranial changes during Triceratops ontogeny" (Abstract)
Museum of the Rockies homepage
Technorati: horns, triceratops, eyes, dinosaur, study, plant-eating, creature, bony, head, frill, cretaceous, period, dinosaurs, evolve, jack, horner, university, montana, california, berkeley, baby, juvenile, specimens, twists, ontogeny, science, evolution, palaeontology, paleontology, big, sky, museum, rockies, video
The first comparison of human and Neanderthal DNA shows that the two lineages diverged about 400,000 years ago and that Neanderthals may have had more DNA in common with chimps than with modern humans.
There is ongoing debate over whether the Neanderthals were a separate species, Homo neanderthalensis, or a subspecies of Homo sapiens. The first Neanderthals are thought to have emerged about 350,000 years ago, so the new findings from this DNA analysis strongly favour the theory that modern humans and Neanderthals share a common ancestor but are not more closely related than that.
Genetic analysis of Neanderthals is very tricky because mere fragments of nuclear DNA have been recoverable from fossils. Previous analyses have focused on mitochondrial DNA samples, which survive better.
...James Noonan will present the findings at the American Society of Human Genetics meeting in New Orleans, US, this week. [Science, Chimpanzees, Evolution, Neandertal, Neandertals]
Technorati: comparison, human, neanderthal, dna, lineages, diverged, chimps, humans, neanderthals, homo, neanderthalensis, subspecies, sapiens, analysis, theory, modern, common ancestor, genetic, nuclear, fossils, mitochondrial, samples, survive, american, society, genetics, new orleans, us, science, chimpanzees, neandertal, neandertals, new scientist
The human brain may have evolved beyond that of our primate cousins because our brain cells are better at sticking in place, researchers say.
A new study comparing the genomes of humans, chimps, monkeys and mice found an unexpectedly high degree of genetic difference in the human DNA regions that influence nerve cell adhesion, compared with the DNA of the other animals.
Accelerated evolution here allowed human brain cell connections to form with greater complexity, enabling us to grow bigger brains, the researchers suggest."
The genetic assembly of the ten billion neurons in the human brain relies on precise expression of adhesion molecules that allow for thousands of connections between neurons and the matrix of proteins around them.
...Prabhakar will present the findings at the American Society of Human Genetics meeting in New Orleans, US, this week. [Chimpanzees, Science, Genome]
Continued at "DNA trail points to human brain evolution (New Scientist)"
Technorati: human, brain, evolved, primate, cells, study, genomes, humans, chimps, monkeys, mice, genetic, difference, dna, nerve, cell, adhesion, animals, accelerated, evolution, complexity, neurons, molecules, american, society, genetics, matrix, proteins, new orleans, chimpanzees, science, genome, new scientist
Scientists revealed today that a prolific parasite is helping shape the destiny of a species it does not even infect. The complex relationship between the parasite, its host, and the unconnected species is the first known example of evolutionary pressure from such a remote source.
Five years ago, University of Rochester scientists linked the bacterial parasite, Wolbachia, to the separation of a single wasp species into two distinct species. Now, researchers have found that this same parasite in fruit flies is not only meddling with the sexual behavior of its host, but may be causing a change in the sexual behavior of a species that is not infected.
"Darwin's model of evolution is based on genetic variation that causes differences in survival and reproduction," says John Jaenike (homepage), professor of biology. "However, this apparently simple scheme can operate in very complex and indirect ways." [Science, Behaviour, Fly]
Based on the open access PLoS Biology paper "Asymmetrical Reinforcement and Wolbachia Infection in Drosophila"
Technorati: science, biology, evolution, parasite, species, infect, host, evolutionary, pressure, remote, source, university, rochester, bacterial, wolbachia, fruit, flies, fly, drosophila, sexual, behavior, behaviour, darwin, genetic, variation, survival, reproduction, sex, plos, open access
Hunters stalked giant camels as tall as some modern-day elephants in the Syrian desert tens of thousands of years ago and archaeologists behind the find are wondering where the camels came from and what caused them to die off.
The enormous beasts existed about 100,000 years ago and more of the bones, first discovered last year, have been found this year in the sands about 150 miles north of the capital, Damascus.
The animal, branded the "Syrian Camel" by its Swiss and Syrian discoverers, stood between three and four yards high - about twice the size of latter-day camels and the height at the shoulder of many African elephants.
Continued at "Scientists find more bones of big camels"
Original blog entry "Remains of giant 100,000-year-old camel discovered in Syria":
Damascus, Syria, October 6 2006 (Reuters) - Swiss researchers have discovered the 100,000-year-old remains of a previously unknown giant camel species in central Syria.
'This is a big discovery, a revolution in science,'. Professor Jean-Marie Le Tensorer of the University of Basel told Reuters. 'It was not known that the dromedary was present in the Middle East more than 10,000 years ago.'
'Can you imagine? The camel's shoulders stood three metres (yards) high and it was around four metres tall, as big as a giraffe or an elephant. Nobody knew that such a species had existed.'
A group of humans apparently killed the camel while it was drinking from a spring, said Tensorer, adding that 100,000-year-old human remains were discovered nearby...
...The human bones were transported to Switzerland, where they underwent anthropological analysis...
..."The bone is that of a homo sapiens, or modern man, but the tooth is extremely archaic, similar to that of a Neanderthal. We don't know yet what it is exactly." said Tensorer. [Neandertal]
Continued at: Remains of giant camel discovered in Syria
Also reported by SANA (Syrian Arab News Agency): "Huge Camel Lived 100,000 Years Before in the Syrian Desert"
damascus, syria, reuters, swiss, unknown, giant, camel, species, discovery, science, tensorer, university, basel, dromedary, middle east, giraffe, elephant, human, remains, spring, bones, switzerland, homo sapiens, bone, modern, man, archaic, neanderthal, sana, syrian, arab, news, agency, neandertal, evolution
Tuesday, October 10, 2006
Hail to the Hornworts: New Plant Family Tree Sheds Light on Evolution of Life Cycles
In the history of life on earth, one intriguing mystery is how plants made the transition from water to land and then went on to diversify into the array of vegetation we see today, from simple mosses and liverworts to towering redwoods.
A research team led by University of Michigan evolutionary biologist Yin-Long Qiu has new findings that help resolve long-debated questions about the origin and evolution of land plants. The work has been published in the Proceedings of the National Academy of Sciences.
Two major steps kicked off the chain of events that helped land plants prosper, forming the basis for modern land-based ecosystems and fundamentally altering the course of evolution of life on earth, said Qiu. The first step was the colonization of land by descendents of aquatic plants known as charophyte algae. That event opened up a vast new world where the sun's intensity was undiminished by passage through water and where carbon dioxide - another essential ingredient for plant life - was abundant.
The second event was a key change in plant life cycles. Plants exhibit a phenomenon known as alternation of generations, in which two alternating forms with different amounts of DNA make up a complete life cycle. One form, known as a sporophyte, produces spores, which grow into individuals of the other form, called gametophytes. Gametophytes produce gametes - eggs and sperm - which unite to form a fertilized egg capable of becoming a new sporophyte, thus completing a life cycle.
While all plants exhibit alternation of generations, some spend most of their life cycle as sporophytes, and others spend more time in the gametophyte phase.
"Early in the history of plant evolution, a shift occurred," says Qiu, assistant professor of ecology and evolutionary biology. "If you look at the so-called 'lower' plants, such as algae, liverworts and mosses, they spend most of their life cycle as gametophytes. But if you look at plants like ferns, pines and flowering plants, they spend most of their time as sporophytes. Geneticists, developmental biologists and evolutionists have been wondering how the switch happened and have put forth two competing hypotheses."
For each hypothesis, scientists have come up with an evolutionary scheme showing how different plant lineages should be related to explain the generation shift. Studies over the last century have produced conflicting results on relationships among early land plant lineages, leaving unanswered the most critical question of how the shift in alternation of generations occurred.
Qiu's group used three complementary sets of genetic data, involving more than 700 gene sequences, to resolve relationships among the four major lineages of land plants: liverworts, mosses, hornworts and vascular plants (which include ferns, pines and flowering plants).
Their analysis showed that liverworts - tiny green, ribbon-like plants often found along river banks - represent the first lineage that diverged from other land plants when charophyte algae first came onto land, and an obscure group called hornworts, often found in abandoned corn fields, represents the progenitors of the vascular plants.
"Basically we captured a few major events that happened in the first few tens of millions of years of land plant evolution," Qiu says. The results make sense in light of the plants' life cycle patterns.
Charophyte algae, liverworts and mosses spend most of the cycle in a free-living gametophyte phase; the sporophyte is a small, short-lived organism that lives on the gametophyte. Vascular plants, on the other hand, spend most of their time as free-living sporophytes, with small, short-lived, gametophytes that often live on the sporophytes.
Hornworts may hold a clue to understanding how this shift happened, as they spend most of their life cycle in the gametophyte phase, but their sporophytes - unlike those of liverworts and mosses - show a tendency to become free-living.
Understanding evolutionary relationships among plant groups is crucial to understanding their biology, just as understanding relationships among primates advances our knowledge of human behavior, anatomy and physiology, Qiu says.
"As humans, we're always interested in knowing where we came from and why we are different from other primates," Qiu says. "Now that we know, from phylogenetic analyses, that our closest relative is the chimpanzee, we can compare the chimpanzee genome with our own genome and compare the chimpanzee brain with our own brain and compare chimpanzee behavior with human behavior.
"But this all assumes we know the chimpanzee is our brother. What if we didn't know? Understanding evolutionary history really is the foundation of biology, and with today's emphasis on biofuels and medically important plants, it should be clear how important it is to learn the evolutionary history of all the organisms on our planet."
Qiu collaborated on the project with 20 other researchers from U-M; the University of Massachusetts, Amherst; the Chinese Academy of Sciences; Universitat Bonn in Germany; the University of Chicago; Southern Illinois University; the University of Akron in Ohio; Freie Universitat Berlin in Germany; Dresden University of Technology in Germany and Harvard University. The U.S. National Science Foundation, the National Natural Science Foundation of China and the Michigan Society of Fellows provided funding.
Source: University of Michigan PR (Adapted) October 4, 2006
Based on the paper:
The deepest divergences in land plants inferred from phylogenomic evidence
Yin-Long Qiu et al.
PNAS | October 17, 2006 | vol. 103 | no. 42 | 15511-15516
Phylogenetic relationships among the four major lineages of land plants (liverworts, mosses, hornworts, and vascular plants) remain vigorously contested; their resolution is essential to our understanding of the origin and early evolution of land plants. We analyzed three different complementary data sets: a multigene supermatrix, a genomic structural character matrix, and a chloroplast genome sequence matrix, using maximum likelihood, maximum parsimony, and compatibility methods. Analyses of all three data sets strongly supported liverworts as the sister to all other land plants, and analyses of the multigene and chloroplast genome matrices provided moderate to strong support for hornworts as the sister to vascular plants. These results highlight the important roles of liverworts and hornworts in two major events of plant evolution: the water-to-land transition and the change from a haploid gametophyte generation-dominant life cycle in bryophytes to a diploid sporophyte generation-dominant life cycle in vascular plants. This study also demonstrates the importance of using a multifaceted approach to resolve difficult nodes in the tree of life. In particular, it is shown here that densely sampled taxon trees built with multiple genes provide an indispensable test of taxon-sparse trees inferred from genome sequences.
The Detroit Free Press: The State Board of Education on Tuesday approved public school curriculum guidelines that support the teaching of evolution in science classes - but not intelligent design.
Intelligent design instruction could be left for other classes in Michigan schools. But it shouldn't have a home in science class, based on the unanimously adopted guidelines.
"The intent of the board needs to be very clear," said board member John Austin, an Ann Arbor Democrat. "Evolution is not under stress. It is not untested science."
Some science groups and the American Civil Liberties Union had worried that state standards would not be strong enough to prevent the discussion of intelligent design as the course expectations developed over the summer.
Continued at "Evolution wins out in Michigan science curriculum debate"
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A 'General Interest' article: "Biomimicry is a new way of viewing and valuing nature. It introduces an era based not on what we can extract from the natural world, but on what we can learn from it."
Northern Great Plains, Inc., Red River Valley Research Corridor Coordinating Center, North Dakota State University, University of Minnesota, Crookston and University of North Dakota are co-hosting four regional presentations on a fascinating new science, Biomimicry. The presentations, 'Biomimicry: Fostering Innovations Inspired by Nature,' are free and open to the public.
'Innovation inspired by Nature Biomimicry: The New Science of Design' will be presented at UMC on Tuesday, October 17, from 7 to 8:30 p.m. in Bede Ballroom. Other presentations include two sessions in Fargo and one at UND on Oct. 16 and 17.
Continued at "New science 'Biomimicry' in the spotlight
See the biomimicry.net website.
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