Posted on 12/18/2001 5:07:16 PM PST by Map Kernow
LONG-LOST relatives of the human race have been traced for the first time. They live at the bottom of puddles. A family of humble microbes has been found to carry a special signalling gene that was previously known only in the animal kingdom. The discovery suggests that the single-celled creatures represent a vital staging post in evolution and that all animal life on Earth descended from something very like them.
The survivor from our ancient ancestors is the collar flagellate or choanoflagellate a microscopic organism that uses a sperm-like tail to swim through shallow water, grazing on bacteria that lodge in its feeding collars.
Its remarkable evolutionary legacy, which stretches back at least 600 million years, has been identified by researchers in the US. Today 150 species of collar flagellates exist around the world, but evolution also gave rise to a more complex lineage that eventually led to the animal kingdom.
They are the closest nonanimal organism to animals, said Sean Carroll, Professor of Genetics at the University of Wisconsin-Madison, who led the research. They are to animals what chimps are to humans, and by studying some of their genetic characteristics, we can begin to make some strong inferences.
In the study, published today in the Proceedings of the National Academy of Sciences, Professor Carroll and his colleague Nicole King analysed proteins from a species of collar flagellate called Monosiga brevicollis. They located a type of signalling gene, receptor tyrosine kinase (RTK), which sends messages to other genes telling them to become active or making them dormant. It is almost identical to similar version found in animals as diverse as humans and sponges.
The findings support strongly the idea that many genes that animals use today were already in place and available on the eve of animal evolution, but changed in function with the step forward to multicellular organisms with distinct body plans and systems of organs.
The microbes, which measure five thousandths of a millimetre in diameter, are protazoans simple organisms that were once regarded as animals but are now generally considered to be part of a separate kingdom, the single-celled protists.
Scientists consider the moment at which multi-celled animals, or metazoa, evolved from the protozoans to be one of the turning points in the history of life on Earth. The process is thought to have taken place about 600 million years ago.
The question is, who were the ancestors of animals and what genetic tools did they pass down to the original animals, Professor Carroll said. The evolution of the metazoa from the protozoans is one of the milestones in the history of life. To build a multicellular organism compatible with a multicellular lifestyle is something that is very difficult. It takes a lot of genetic machinery to do that, and you have to ask the question, did it all arise when the animals came along, or was some of it in place earlier? Were starting to get a glimpse of the genetic tool kit we have in common. In choanoflagellates, weve found genes that previously were believed only to exist in animals. Its a confirmation of the idea that the genes come first, before their exploitation by organisms.
The study concludes: We have discovered in M. brevicollis the first RTK, to our knowledge, identified outside the metazoa. The architecture . . . resembles that of RTKs in sponges and humans and suggests the ability to receive and transduce signals. Thus, choanoflagellates express genes involved in animal development that are not found in other eukaryotes (complex organisms), and that may be linked to the origin of the metazoa.
My humblest apologies. You are correct. I should have stated the laws of nature are proof to ME that he exists. Where there are laws, there is a law maker....
NO, the four laws of physics have always been...well, they started at the big bang or creation event... no, I mean they existed in this unthinkable void before the creation... I don't know I just know there is no God...
[Pooh-Bah]
Don't mention it. I am, in point of fact, a particularly haughty and exclusive person of pre-Adamite ancestral descent. You will understand this when I tell you that I can trace my ancestry back to a protoplasmal primordial atomic globule. Consequently, my family pride is something inconceivable. . . ---- The Mikado, Act I
In general, I find assertions that concurrently assert a statement AND it's negation to be suspect.
In particular, your statement is factually inaccurate. Big Bang cosmology posits that time began along with space; there is no "before" the Big Bang, as there is no "time" in which to establish a temporal order until the "Big Bang" took place.
And you know this because........
(NEWARK) - A Rutgers-Newark biology professor who serves as president of the American Institute of Biological Sciences (AIBS) is leading a nationwide effort to defend the theory of evolution in the face of what the institute views as opposition and indifference from school boards and government entities.
Rutgers-Newark Biology Professor Judith S. Weis, president of the AIBS, a Washington, D.C.-based professional organization begun in 1947, believes that the teaching of evolution in America is being diminished and minimized by the teaching of creationism as well as an overall lack of teaching Darwin's theory of evolution in high school.
"There's nothing that requires schools to teach evolution. Sometimes teachers in high schools just leave it out. However, from the point of view of biologists, evolution is the central theory of biology upon which everything is based," said Weis. "Unfortunately, teaching evolution has become a political issue in many parts of the country and AIBS as a representative of biologists wanted to be a major force speaking out in favor of its teaching."
Weis said the institute is working together with the American Geological Institute, the National Association of Biology Teachers, and its 80-plus member organizations to address the political and legislative threats to teaching evolution.
In states challenging its teaching, the institute responds by sending letters to school boards, state legislatures, providing testimony at public meetings, and notifying members and affiliated organizations. She said a national AIBS conference, "Evolution: Understanding Life on Earth," planned for March 2002 in Arlington, Virginia, will focus more attention on the teaching of evolutionary biology in America.
The AIBS, with more than 80 member societies and 250,000 members, has established an e-mail system that enables scientists and teachers in each state, and member societies, to keep each other informed about threats to the teaching of evolution.
Darwin's theory of evolution holds that living things change and adapt to their environment and that present day species (including human beings) are descended from earlier species through modification by natural selection.
The theory has been accepted by scientists for nearly 100 years, Weis said, and has been refined, extended, and strengthened over the years by findings in paleontology and developmental biology.
Furthermore, discoveries in genetics, molecular biology, and genomics - all of which have significant benefits for human health - would not be possible without the underlying knowledge of evolution. And, Weis adds, "modern molecular biology and genomics have increased our understanding of how evolution works."
Nonetheless, evolution remains a politically, if not scientifically, controversial issue.
Weis said that this year alone, seven states have had either local or statewide efforts to water down the teaching of evolution, or "balance" it with the teaching of creationism - a religious belief that different species were created separately by a higher power, such as God. States with such efforts included Arkansas, Michigan, Louisiana, Pennsylvania, Minnesota, Georgia, and Hawaii.
"Rarely does anyone now use the word 'creationism,' because that's too obvious," Weis said. "The current terminology is 'intelligent design.' Efforts to teach evolution as a theory, not a fact, reflect misconceptions about the nature of science. A theory in science is not just a speculation or a guess, but a concept with a large amount of information supporting it," said Weis.
"I see a core part of my field as being under attack. Polls have shown that a majority of people do not understand the theory of evolution and others show that people do not accept evolution theory because teachers do not teach it," Weis said. "When confronted with the possibility of local objections," she said, "some teachers find it easier to not teach the subject."
For information about the AIBS efforts, visit the AIBS Web site at http://www.aibs.org. The site includes resources for teaching evolution.
Your are quite correct. My statement was nebulous which is why I put time in quotes. I apologize for not being more lucid. Hawkings, Davies and a myriad of other astophysicits have demostrated that time and space originated simultaneuosly. The space-time theorem. Scientists finally seem to be where theologians have been for centuries. Not that they should give up the quest for discovering truth, or we will end up in another dark ages.
"He tracks this process backwards some 3 billion years "
Yes, that's more the scale I was looking toward.
best regards
The laws of quantum mechanics allow lots of things to happen without a cause.
The universe may be just one of those things.
I would ask you: what caused matter to arise from nothing? How did something come from nothing-nothing, as in no forces, no matter, no energy, just nothing. I contest this, and the origin of life, needs something beyond observable science-indeed, we can never prove the exact origin of the universe. We can try, and accumulate evidence to support various theory's, but we can not prove it (or do you disagree?). Presumably, science should look for the best possible answer in such a scenrio, correct? Why then should science not at least allow for the existence of an Intelligent Creator beyond the natural sphere? There wer scientists in years past (still are some around) that did not believe in Darwin's Theory, and incredibly, they made important discoveries quite well.
A simple quantum event. Next?
Because it no more contributes to understanding what really happened than to say "the magical dog did it."
Really, you should read more before jumping in trying to make a point.
Nice try. Quantum mechanics is founded on the concept that there are finite probabilities for quantum events to take place within certain time intervals. the greater the time interval ther greater the probability. But without time there is no quatum event possible. The orgin of time space and matter eliminates quantum tunneling as "creator".
Too funny.
You are so wrong in your characterization one does not know where to begin.
You also left out the idea that there must be an observer.
Ah - the lay misunderstanding of Heisenberg comes into play. Not even related.
Not that anyone completly understands quatum science, but lets not hide behind the unknown to avoid good questions.
That's the problem - you do not pose good questions.
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