Posted on 05/08/2003 10:11:06 AM PDT by Nebullis
Arlington, Va.—If the evolution of complex organisms were a road trip, then the simple country drives are what get you there. And sometimes even potholes along the way are important.
An interdisciplinary team of scientists at Michigan State University and the California Institute of Technology, with the help of powerful computers, has used a kind of artificial life, or ALife, to create a road map detailing the evolution of complex organisms, an old problem in biology.
In an article in the May 8 issue of the international journal Nature, Richard Lenski, Charles Ofria, Robert Pennock, and Christoph Adami report that the path to complex organisms is paved with a long series of simple functions, each unremarkable if viewed in isolation. "This project addresses a fundamental criticism of the theory of evolution, how complex functions arise from mutation and natural selection," said Sam Scheiner, program director in the division of environmental biology at the National Science Foundation (NSF), which funded the research through its Biocomplexity in the Environment initiative. "These simulations will help direct research on living systems and will provide understanding of the origins of biocomplexity."
Some mutations that cause damage in the short term ultimately become a positive force in the genetic pedigree of a complex organism. "The little things, they definitely count," said Lenski of Michigan State, the paper's lead author. "Our work allowed us to see how the most complex functions are built up from simpler and simpler functions. We also saw that some mutations looked like bad events when they happened, but turned out to be really important for the evolution of the population over a long period of time."
In the key phrase, "a long period of time," lies the magic of ALife. Lenski teamed up with Adami, a scientist at Caltech's Jet Propulsion Laboratory and Ofria, a Michigan State computer scientist, to further explore ALife.
Pennock, a Michigan State philosopher, joined the team to study an artificial world inside a computer, a world in which computer programs take the place of living organisms. These computer programs go forth and multiply, they mutate and they adapt by natural selection.
The program, called Avida, is an artificial petri dish in which organisms not only reproduce, but also perform mathematical calculations to obtain rewards. Their reward is more computer time that they can use for making copies of themselves. Avida randomly adds mutations to the copies, thus spurring natural selection and evolution. The research team watched how these "bugs" adapted and evolved in different environments inside their artificial world.
Avida is the biologist's race car - a really souped up one. To watch the evolution of most living organisms would require thousands of years – without blinking. The digital bugs evolve at lightening speed, and they leave tracks for scientists to study.
"The cool thing is that we can trace the line of descent," Lenski said. "Out of a big population of organisms you can work back to see the pivotal mutations that really mattered during the evolutionary history of the population. The human mind can't sort through so much data, but we developed a tool to find these pivotal events."
There are no missing links with this technology.
Evolutionary theory sometimes struggles to explain the most complex features of organisms. Lenski uses the human eye as an example. It's obviously used for seeing, and it has all sorts of parts - like a lens that can be focused at different distances - that make it well suited for that use. But how did something so complicated as the eye come to be?
Since Charles Darwin, biologists have concluded that such features must have arisen through lots of intermediates and, moreover, that these intermediate structures may once have served different functions from what we see today. The crystalline proteins that make up the lens of the eye, for example, are related to those that serve enzymatic functions unrelated to vision. So, the theory goes, evolution borrowed an existing protein and used it for a new function.
"Over time," Lenski said, "an old structure could be tweaked here and there to improve it for its new function, and that's a lot easier than inventing something entirely new."
That's where ALife sheds light.
"Darwinian evolution is a process that doesn't specify exactly how the evolving information is coded," says Adami, who leads the Digital Life Laboratory at Caltech. "It affects DNA and computer code in much the same way, which allows us to study evolution in this electronic medium."
Many computer scientists and engineers are now using processes based on principles of genetics and evolution to solve complex problems, design working robots, and more. Ofria says that "we can then apply these concepts when trying to decide how best to solve computational problems."
"Evolutionary design," says Pennock, "can often solve problems better than we can using our own intelligence."
Well, everyone else is apparently too stunned by the stupidity rays emanating from this question to answer it, so I'll take a shot.
a) if you mean homogeneously distributed atoms assembling into molecules and heterogenous clumps of stuff, than this can be observed in the formation of planets from dust. You can get the idea of how this could be by observing a child's toy made of iron filing under the influence of a magnet.
b) if you mean atoms producing other atoms, we have our sun for an example, which keeps us alive by zipping together heavier molecules from lighter molecules.
Which is, of course, totally irrelevant, since you did not pin their junctions together to get the tunneling effect of the PN pair regulating the net output. Had you attempted to do so with your soldering iron, you would have, of course, melted the containers.
The weak force is the force that induces beta decay via interaction with neutrinos. A star “burns” by a nuclear fusion process. Three of those processes are proton-to proton fusion, helium fusion, and the carbon cycle. Here is an example of proton-to-proton fusion, which is the process our own sun uses: (two protons fuse -> via neutrino interaction one of the protons transmutes to a neutron to form deuterium -> combines with another proton to form a helium nuclei -> two helium nuclei fuse releasing alpha particles and two protons). The weak force is also necessary for the formation of the elements above iron. Due to the curve of binding energy (iron has the most tightly bound nucleus), nuclear forces within a star cannot form any element above iron in the periodic table. So it is believed that all higher elements were formed in the vast energies of supernovae. In this explosion large fluxes of energetic neutrons are produced which produce the heavier elements by nuclei bombardment. This process could not take place without neutrino involvement and the weak force.
Sigh! I kinda figured that out when he argued that circles were not a type of ellipse.
Which, of course, makes my original statement, that a transistor was in a sense two diodes back-to-back, entirely correct. But you still have the gall to continue the discussion. It is now ended. You have verified my original statement.
Actually the term 'phyla' only refers to animals.
AAAAAAAHAHAHAHAHAHAHAHAHA!!!! Man, that's a good one. That ranks right up there with your other many "scientific blunders that even a junior-high-school student would be too educated to make".
So "the term 'phyla' only refers to animals, eh? That'll come as a huge surprise to the botanists who have been using the term for plant taxa for over a couple hundred years now... While it's true that Linnaeus, the father of taxonomy, preferred to use the term "Division" for plants and "Phylum" for animals (for the same level of classification), the inconsistent choice was a contentious one from the start, and many generations of biologists have chosen to use "phylum" for plants as well as animals. Which term was "preferred" has been a long-standing point of argument among botanists, until it was finally settled by the 1993 International Code of Botanical Nomenclature conference of standards, which authoritatively declared that *both* are perfectly acceptable (and exactly interchangeable) when applied to plants.
So no, saying "phyla" does *not* automatically mean that one is talking about animals, nor has it ever, except for a short time in the 1800's (and even then only until biologists began refining Linnaeus's original suggestions).
Where have you been the past 200 years?
Here, check this out and learn something: Survey of the botanical Phyla
My speaking of 'animal' phyla is merely for the benefit of the non-technical reader that may not be aware that I am only speaking of animals not plants.
Keep telling yourself that, and you might start to believe it yourself. The rest of us aren't so gullible, though.
I also use it because ignorant (and dishonest) evolutionists, ever trying to create confusion tend to bring out plants as a contradiction of the uniqueness of what happened in the Cambrian.
Because they are.
Creationists want to try to give the impression that there was some kind of non-evolutionary act of "creation" during the Cambrian. Even for animals such an implication falls apart when you look at the evidence, but it's obviously even more of a fraud when one looks at the rise of complex plants, which happened in more recent times. This means that the Cambrian was hardly a "let there be..." time for all life, and also allows the gradual evolution of plant life to be better represented in the fossil record (since it happend during eras for which we have more numerous and complete fossil collections), which puts the lie to the creationist implication that the origins of all kinds of life are shrouded in unobservable (and therefore mysterious) clouds of the unknown. Quite simply, there is no "Cambrian explosion" for plants. Their evolution is clear. That's why creationists would prefer to draw attention away from plant evolution and to the currently lesser-documented early animal evolution.
Further, your statement that plant evolution continued according to Darwinian postulates is false. The only major classification of new plants in hundreds of millions of years is flowering plants which arose some 135 million years ago.
Umm... Only if you decide to totally ignore the rise of such "major" changes as the first land-based plants 475 million years ago ("MYA"), reproduction via seeds 375 MYA, vascular plants 360 MYA (i.e. plants with a system for transporting nutrients and water up/down the plant), specialized leaves 340 MYA, woody secondary growth 320 MYA (which made possible strong, tall plants such as trees and others -- prior to this all plants were thin, ropy organisms which grew only from their branch tips and could not become wider and stronger at the base as they aged), etc...
Flowering plants are a problem for evolution also since they require a symbiotic relationship with animals which is difficult to justify in evolutionary terms.
Are you daft? The evolution of symbiotic relationships is well understood. Each "party" benefits, so each species has an evolutionary advantage (and thus selective pressure) for further developing the relationship. Voila, co-evolution results. Simple.
I would give a link to the following, but the main page is offline, so I have no choice but to cut-and-paste Google's cached copy:
Now, which part of that was so hard to figure out on your own?COEVOLUTION OF THE ANGIOSPERMS AND THEIR INSECT POLLINATORS
Plants, unlike animals, are in general immobile. Thus, the uniting of egg and sperms from separate individuals for reproduction presents them with difficulties not faced by mobile creatures. Impelled by the urge to mate, mate and female animals can swim, crawl, walk or fly until they find a suitable partner. But plants, anchored by their roots to separate spots of ground, need the intervention of a third party. The pollen of one plant must be carried to the ovules of another by an external agent such as wind, mammals, birds or insects.
It is inevitable that wind will pick up and carry pollen if it is in its path and early plants, like modern gymnosperms, relied on wind pollination. They evolved female reproductive structures with sticky sap-covered ovules in order to catch the wind-carried pollen and they also evolved separate male structures adapted to producing and dispersing copious amounts of pollen. But wind as a pollinator is uncontrollable and unreliable and any adaptation that increases the chances of pollen being carried to another member of the same species would be favored. Thus, the door to insect pollination and the evolution of flowers was open.
The fossil record indicates that flowers originated during the middle Mesozoic Era approximately 150 million years ago. It is likely that beetles that fed on plant tissue during that time discovered the sap-covered ovules and pollen to be nutritious foods. Some beetles returning regularly to the new food sources accidentally carried pollen to the ovules. This new method of pollination represented a more efficient method of cross pollination than releasing huge quantities of pollen into the air. Through natural selection, plants developed adaptations to allow more successful beetle pollination such as carpels to protect the ovaries from the beetles' chewing jaws. Also, the male pollen-producing stamens and the female ovary-containing carpels moved closer together to increase the chances that the beetle would carry pollen between the two. In some flowers, the stamens and carpels are grouped within the same flower.
The more attractive the plants' flowers were to the insect, the more often they would be visited and the more seeds they could produce. Any variations that attracted insects were selected for by natural selection. Nectaries that secrete sweet nectar as a food reward evolved. Also, some of the outer stamens became sterile and brightly-colored, becoming petals to visually attract the pollinators and give them a place to land.
By the beginning of the Cenozoic era, approximately 65 million years ago, the symbiotic relationship between flowering plants and insect pollinators had become entrenched. Groups of insects such as bees, butterflies and moths had evolved and were dependent on flowers as their main or only food sources. From this time on, flowering plants and their insect pollinators have had a profound effect on each other.
Much of the beauty and variety of floral color, odor and anatomy is due to the adaptations of plants to their specialized pollinators. Plants that are visited by one or a very few kinds of pollinators have an advantage over plants visited by many different kinds of pollinators, since a more specialized pollinator is less likely to deposit its pollen on the flower of another species. It is also advantageous for the pollinator to specialize on a particular flower type and have an exclusive food supply that is inaccessible to a competing species.
Many of the distinctive features of modern flowers are special adaptations that encourage a particular pollinator and restrict others. The yellow color, sweet smell and stable landing platform offered by the petals of the prickly saxifrage flower in Figure 1 allow the bumble bee to recognize it and land. Bees are a good pollinator for this flower, since they have a visual spectrum restricted to yellows and blues, they are attracted to sweet smells and they tend to feed on only one flower type at a time. In Figure 2, you see an aster flower which is adapted to butterfly pollination,. The narrow and deep nectaries of these flowers restrict insects that lack a long narrow tongue like that of the butterfly. In many cases, the depth of a flower's nectaries closely matches the tongue length of the butterfly or moth that pollinated it.
The last two figures show that co-evolution toward mutually beneficial symbiosis with insects is by no means the only way that plants ensure their pollination. Figure 3 shows you a flower with a downward-hanging nectary, adapted for pollination by a hovering hummingbird like the Calliope hummingbird shown. Figure 4 shows you that mutualism - with benefits to both partners - is not the only way plants can get insects to carry their pollen. In this example, the male wasp is being duped into thinking that the orchid flower is a female of the same species. Through mimicry, the orchid is pollinated as the wasp travels from flower to flower seeking a mate.
What's this we business? I stopped posting to him a year ago. Since then I've watched you bang your head against the wall.
I suppose. When a guy's main weapon is being born again dumb as a stump every day, it could be a clue that you're wasting your time.
Vertebrates are chordates, but chordates are not vertebrates
No kidding, bunky, which is why I had to correct you on that point.
and both phylum have now been found to have arisen during the Cambrian explosion
"Both phylum"? First, "phylum" is singular -- surely you mean "both phyla". Second, precisely *because* "Vertebrates are chordates, but chordates are not vertebrates", they can't *BOTH* be "phyla". Vertebrates are a *subgroup* of the phyla Chordata. There is no such thing as the "vertebrate phylum", as you incorrectly stated in a prior post, which is why I *already corrected you* on the matter. Try to keep up, eh?
Now when one considers that it took more than 200 million years for the (supposed) evolution from amhibians to reptiles to mammals
Actually, no more than 100-150 million.
- a far smaller change than that required from any of the prior existing phyla to the ones found in the Cambrian (or even to the changes required for one of the Cambrian species to arise from another),
I'm sorry, you forgot to document your assertion that the amphibian to mammal evolution is somehow "a far smaller change" than any change during the Cambrian. Feel free to present your original research papers on that subject. We'll wait.
If we're just going on personal estimates (and clearly, *you* are), it seems to me that the amphibian to mammal transition is a far greater leap (including as it does egg-laying to live birth, cold-blooded to warm-blooded, abandonment of eggs to raising and feeding of offspring, living significant time in water versus entirely land-based living, dramatically increased brain size, improved immune system, four-chamber heart, etc. etc.) than the less drastic Cambrian changes of simply one shape of underwater life to another.
But hey, you keep imagining anything you want. Just don't mistake it for facts.
the evidence shows clearly the impossibility of evolution. The time involved for the numerous and dramatic changes required for all those changes is simply not enough for them to have occurred according to gradualistic Darwinian evolution.
...because...? Again, you are invited to present your research papers on this topic. In the meantime, I think I'll go with the conclusions of the folks who *have* studied this issue in far more depth than a guy who wasn't even aware that plants had phyla..
Furthermore, you have *again* totally failed to deal with the scenario I spelled out a while back in words small enough even for you, involving an isolated basin of evolution during the pre-Cambrian during which evolution took place at a leisurely pace, then (due to the continental breakup at the time) spilled its results out into the rest of the oceans, making for only an apparent "explosion" in the fossil record elsewhere. Biologists don't overlook this possible scenario -- why do you? Oh, right, because you have no good rebuttal for it.
This is especially so since many of the phyla we are speaking of were sexual creatures
Okay, I'll bite -- exactly how can you claim to know that "many of" the Cambrian-era organisms reproduced sexually?
and the problems created by sexual reproduction for evolution are quite dramatic. It requires that not one, but at least two organisms of the transforming species continually have sufficiently close mutations to allow them to continue reproducing.
Oh, for pete's sake. The mechanism of the evolution of sexual dimophism has been explained to you over and over again. How many more times are you going to pretend not to have learned anything about it? Hint to jog your failing memory: Sexual dimorphism does *not* need to develop as in your ludicrous scenario above. There are many more "easy" routes for evolution to take.
It such dramatic changes could occur in several organisms at the same time to allow them to maintain reproductive viability is totally ludicrous
...only in your straw man version of it. The *actual* pathways, as we've explained to you multiple times, Mr. Troll, are far less "ludicrous".
and shows Darwinian evolution to be what it always was - charlatanism, not science.
Only in your own fevered imagination.
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