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Artificial Life Experiments Show How Complex Functions Can Evolve
NSF ^ | May 8, 2003 | Staff

Posted on 05/08/2003 10:11:06 AM PDT by Nebullis

Artificial Life Experiments Show How Complex Functions Can Evolve

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."

TOPICS: Culture/Society; Miscellaneous; News/Current Events
KEYWORDS: ai; crevolist
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To: RadioAstronomer
Oh yes RA you have to take a peek at this one, it's a scream!! ;)
641 posted on 05/08/2003 10:15:24 PM PDT by Aric2000 (Are you on Grampa Dave's team? I am!! $5 a month is all it takes, come join!!!)
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To: plusone
The problem with this program is that there are no predators to come along and eat up the evolving life forms.

Are you sure? I didn't see enough in the write-up to answer that issue one way or the other.

Furthermore, I've done some ALife evolution of my own, and the little buggers evolved predator-prey relationships *all by themselves* (as well as "viral" and "parasitic" modes of success) without me putting it in originally.

In any case, why would it *have* to have predation to get results?

The ALife has been left alone to change on its own without worrying about becoming someone else's dinner.

So? There are plenty of other selective pressures and reproductive hazards other than getting literally eaten.

So if you have some partial adaptation, for example, a proto eye that confers no real advantage to you, you may not live the 100,000 generations is supposedly takes for a real eye to evolve and become useful.

That grossly misstates the situation. First, proto-eyes are at least partially useful from the start. They don't have to wait "100,000 generations" to "become useful". Even a poor light-sensing organ is better than none (and plenty of real-life organisms get by just fine with nothing more than "is it dark or is it light" sensors).

Second, while it's true that the first thing with a primitive eyespot might get eaten (or lose the "rat race" of life in any other number of ways), all it takes is for one to eventually *not* get eaten (i.e., successfully reprodue) to start the path down the road to bigger and better things. It's not the offspring that fail which write the "book of life", it's the ones that manage to beat the odds and make it anyway.

642 posted on 05/08/2003 10:50:12 PM PDT by Ichneumon
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To: Aric2000
Maybe it's absurd to you, but you're not the one with DR in front of your name either.

Ah, the old "Appeal to Authority" fallacy. Dr Brigitte Boisselier says she cloned a human, I take it you believe here. Chuckle, Guffaw.

Also, evolutionary programs have actually created circuits that work BETTER then human designed ones, and we can't figure out how they work. All we know is that they DO work, and many have been patented.

Now is your opportunity to show us a few. I think someone might have difficulty getting a patent for something that they cannot explain the workings, but you never know.

643 posted on 05/08/2003 11:47:48 PM PDT by AndrewC
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To: nmh
Nothing but godless evolution with absolutely NO evidence to support it. Fossils don't show ANY transitional species

Funny, I showed you a great deal of that evidence on a thread a week or two ago.

So... Are you suffering from some sort of tragic amnesia, or are you just bearing false witness?

For newcomers, here's a post I wrote last week in response to a creationist challenging us for specific transitional forms:

Show me transitional forms from one species to another!

Here's several hundreds for you:

Transitional Vertebrate Fossils FAQ

I want to see intermediaries of fish to elephant...come on.

Okay, if you insist:

Fish to Amphibian transition:

1. Cheirolepis, (early Devonian, 400 million years ago) -- Primitive bony ray-finned fishes that gave rise to the vast majority of living fish. Heavy acanthodian-type scales, acanthodian-like skull, and big notocord.

2. Osteolepis (mid-Devonian, 390 million years ago) -- One of the earliest crossopterygian lobe-finned fishes, still sharing some characters with the lungfish (the other lobe-finned fishes). Had paired fins with a leg-like arrangement of major limb bones, capable of flexing at the "elbow", and had an early-amphibian-like skull and teeth.

3. Eusthenopteron, Sterropterygion (mid-late Devonian, 380 million years ago) -- Early rhipidistian lobe-finned fish roughly intermediate between early crossopterygian fish and the earliest amphibians. Skull very amphibian-like. Strong amphibian- like backbone. Fins very like early amphibian feet in the overall layout of the major bones, muscle attachments, and bone processes, with tetrapod-like tetrahedral humerus, and tetrapod-like elbow and knee joints. But there are no perceptible "toes", just a set of identical fin rays. Body & skull proportions rather fishlike.

4. Panderichthys, Elpistostege (mid-late Devonian, about 370 Mya) -- These "panderichthyids" are very tetrapod-like lobe-finned fish. Unlike Eusthenopteron, these fish actually look like tetrapods in overall proportions (flattened bodies, dorsally placed orbits, frontal bones! in the skull, straight tails, etc.) and have remarkably foot-like fins.

5. Obruchevichthys(middle Late Devonian, about 370 Mya -- Discovered in 1991 in Scotland, these are the earliest known tetrapod remains. The humerus is mostly tetrapod-like but retains some fish features. The discoverer, Ahlberg (1991), said: "It [the humerus] is more tetrapod-like than any fish humerus, but lacks the characteristic early tetrapod 'L-shape'...this seems to be a primitive, fish-like character....although the tibia clearly belongs to a leg, the humerus differs enough from the early tetrapod pattern to make it uncertain whether the appendage carried digits or a fin. At first sight the combination of two such extremities in the same animal seems highly unlikely on functional grounds. If, however, tetrapod limbs evolved for aquatic rather than terrestrial locomotion, as recently suggested, such a morphology might be perfectly workable."

6. Hynerpeton, Acanthostega, Ichthyostega (late Devonian, 360 Mya) -- A little later, the fin-to-foot transition was almost complete, and we have a set of early tetrapod fossils that clearly did have feet. The most complete are Ichthyostega, Acanthostega gunnari, and the newly described Hynerpeton bassetti (Daeschler et al., 1994). (There are also other genera known from more fragmentary fossils.) Hynerpeton is the earliest of these three genera (365 Ma), but is more advanced in some ways; the other two genera retained more fish- like characters longer than the Hynerpeton lineage did. Acanthostega still had internal gills, adding further support to the suggestion that unique tetrapod characters such as limbs with digits evolved first for use in water rather than for walking on land. Acanthostega also had a remarkably fish-like shoulder and forelimb. Ichthyostega was also very fishlike, retaining a fish-like finned tail, permanent lateral line system, and notochord. It turns out that Acanthostega's front foot had eight toes, and Ichthyostega's hind foot had seven toes, giving both feet the look of a short, stout flipper with many "toe rays" similar to fin rays. All you have to do to a lobe- fin to make it into a many-toed foot like this is curl it, wrapping the fin rays forward around the end of the limb. In fact, this is exactly how feet develop in larval amphibians, from a curled limb bud. Hynerpeton, in contrast, probably did not have internal gills and already had a well-developed shoulder girdle; it could elevate and retract its forelimb strongly, and it had strong muscles that attached the shoulder to the rest of the body (Daeschler et al., 1994).

7. Labyrinthodonts (eg Pholidogaster, Pteroplax) (late Dev./early Miss., 355 Mya) -- These larger amphibians still have some icthyostegid fish features, such as skull bone patterns, labyrinthine tooth dentine, presence & pattern of large palatal tusks, the fish skull hinge, pieces of gill structure between cheek & shoulder, and the vertebral structure. But they have lost several other fish features: the fin rays in the tail are gone, the vertebrae are stronger and interlocking, the nasal passage for air intake is well defined, etc.

Amphibian to Reptile transition:

8. Pholidogaster (Mississippian, about 330 Ma) -- A group of large labrinthodont amphibians, transitional between the early amphibians (the ichthyostegids, described above) and later amphibians such as rhachitomes and anthracosaurs.

9. Proterogyrinus (late Mississippian, 325 Mya) -- Classic labyrinthodont-amphibian skull and teeth, but with reptilian vertebrae, pelvis, humerus, and digits. Still has fish skull hinge. Amphibian ankle. 5-toed hand and a 2-3-4-5-3 (almost reptilian) phalangeal count.

10. Limnoscelis, Tseajaia (late Carboniferous, 300 Mya) -- Amphibians apparently derived from the early anthracosaurs, but with additional reptilian features: structure of braincase, reptilian jaw muscle, expanded neural arches.

11. Solenodonsaurus (mid-Pennsylvanian) -- An incomplete fossil, apparently between the anthracosaurs and the cotylosaurs. Loss of palatal fangs, loss of lateral line on head, etc. Still just a single sacral vertebra, though.

12. Hylonomus, Paleothyris (early Pennsylvanian) -- These are protorothyrids, very early cotylosaurs (primitive reptiles). They were quite little, lizard-sized animals with amphibian-like skulls (amphibian pineal opening, dermal bone, etc.), shoulder, pelvis, & limbs, and intermediate teeth and vertebrae. Rest of skeleton reptilian, with reptilian jaw muscle, no palatal fangs, and spool-shaped vertebral centra. Probably no eardrum yet.

13. Paleothyris (early Pennsylvanian) -- An early captorhinomorph reptile, with no temporal fenestrae at all.

14. Protoclepsydrops haplous (early Pennsylvanian) -- The earliest known synapsid reptile. Little temporal fenestra, with all surrounding bones intact. Had amphibian-type vertebrae with tiny neural processes. (reptiles had only just separated from the amphibians)

15. Clepsydrops (early Pennsylvanian) -- The second earliest known synapsid.

Reptile to Mammal transition:

16. Archaeothyris (early-mid Pennsylvanian) -- A slightly later ophiacodont. Small temporal fenestra, now with some reduced bones (supratemporal). Braincase still just loosely attached to skull. Slight hint of different tooth types. Still has some extremely primitive, amphibian/captorhinid features in the jaw, foot, and skull. Limbs, posture, etc. typically reptilian, though the ilium (major hip bone) was slightly enlarged.

17. Varanops (early Permian) -- Temporal fenestra further enlarged. Braincase floor shows first mammalian tendencies & first signs of stronger attachment to rest of skull (occiput more strongly attached). Lower jaw shows first changes in jaw musculature (slight coronoid eminence). Body narrower, deeper: vertebral column more strongly constructed. Ilium further enlarged, lower-limb musculature starts to change (prominent fourth trochanter on femur). This animal was more mobile and active. Too late to be a true ancestor, and must be a "cousin".

18. Haptodus (late Pennsylvanian) -- One of the first known sphenacodonts, showing the initiation of sphenacodont features while retaining many primitive features of the ophiacodonts. Occiput still more strongly attached to the braincase. Teeth become size-differentiated, with biggest teeth in canine region and fewer teeth overall. Stronger jaw muscles. Vertebrae parts & joints more mammalian. Neural spines on vertebrae longer. Hip strengthened by fusing to three sacral vertebrae instead of just two. Limbs very well developed.

19. Dimetrodon, Sphenacodon or a similar sphenacodont (late Pennsylvanian to early Permian, 270 Ma) -- More advanced pelycosaurs, clearly closely related to the first therapsids (next). Dimetrodon is almost definitely a "cousin" and not a direct ancestor, but as it is known from very complete fossils, it's a good model for sphenacodont anatomy. Medium-sized fenestra. Teeth further differentiated, with small incisors, two huge deep- rooted upper canines on each side, followed by smaller cheek teeth, all replaced continuously. Fully reptilian jaw hinge. Lower jaw bone made of multiple bones & with first signs of a bony prong later involved in the eardrum, but there was no eardrum yet, so these reptiles could only hear ground-borne vibrations (they did have a reptilian middle ear). Vertebrae had still longer neural spines (spectacularly so in Dimetrodon, which had a sail), and longer transverse spines for stronger locomotion muscles.

20. Biarmosuchia (late Permian) -- A therocephalian -- one of the earliest, most primitive therapsids. Several primitive, sphenacodontid features retained: jaw muscles inside the skull, platelike occiput, palatal teeth. New features: Temporal fenestra further enlarged, occupying virtually all of the cheek, with the supratemporal bone completely gone. Occipital plate slanted slightly backwards rather than forwards as in pelycosaurs, and attached still more strongly to the braincase. Upper jaw bone (maxillary) expanded to separate lacrymal from nasal bones, intermediate between early reptiles and later mammals. Still no secondary palate, but the vomer bones of the palate developed a backward extension below the palatine bones. This is the first step toward a secondary palate, and with exactly the same pattern seen in cynodonts. Canine teeth larger, dominating the dentition. Variable tooth replacement: some therocephalians (e.g Scylacosaurus) had just one canine, like mammals, and stopped replacing the canine after reaching adult size. Jaw hinge more mammalian in position and shape, jaw musculature stronger (especially the mammalian jaw muscle). The amphibian-like hinged upper jaw finally became immovable. Vertebrae still sphenacodontid-like. Radical alteration in the method of locomotion, with a much more mobile forelimb, more upright hindlimb, & more mammalian femur & pelvis. Primitive sphenacodontid humerus. The toes were approaching equal length, as in mammals, with #toe bones varying from reptilian to mammalian. The neck & tail vertebrae became distinctly different from trunk vertebrae. Probably had an eardrum in the lower jaw, by the jaw hinge.

21. Procynosuchus (latest Permian) -- The first known cynodont -- a famous group of very mammal-like therapsid reptiles, sometimes considered to be the first mammals. Probably arose from the therocephalians, judging from the distinctive secondary palate and numerous other skull characters. Enormous temporal fossae for very strong jaw muscles, formed by just one of the reptilian jaw muscles, which has now become the mammalian masseter. The large fossae is now bounded only by the thin zygomatic arch (cheekbone to you & me). Secondary palate now composed mainly of palatine bones (mammalian), rather than vomers and maxilla as in older forms; it's still only a partial bony palate (completed in life with soft tissue). Lower incisor teeth was reduced to four (per side), instead of the previous six (early mammals had three). Dentary now is 3/4 of lower jaw; the other bones are now a small complex near the jaw hinge. Jaw hinge still reptilian. Vertebral column starts to look mammalian: first two vertebrae modified for head movements, and lumbar vertebrae start to lose ribs, the first sign of functional division into thoracic and lumbar regions. Scapula beginning to change shape. Further enlargement of the ilium and reduction of the pubis in the hip. A diaphragm may have been present.

22. Dvinia [also "Permocynodon"] (latest Permian) -- Another early cynodont. First signs of teeth that are more than simple stabbing points -- cheek teeth develop a tiny cusp. The temporal fenestra increased still further. Various changes in the floor of the braincase; enlarged brain. The dentary bone was now the major bone of the lower jaw. The other jaw bones that had been present in early reptiles were reduced to a complex of smaller bones near the jaw hinge. Single occipital condyle splitting into two surfaces. The postcranial skeleton of Dvinia is virtually unknown and it is not therefore certain whether the typical features found at the next level had already evolved by this one. Metabolic rate was probably increased, at least approaching homeothermy.

23. Thrinaxodon (early Triassic) -- A more advanced "galesaurid" cynodont. Further development of several of the cynodont features seen already. Temporal fenestra still larger, larger jaw muscle attachments. Bony secondary palate almost complete. Functional division of teeth: incisors (four uppers and three lowers), canines, and then 7-9 cheek teeth with cusps for chewing. The cheek teeth were all alike, though (no premolars & molars), did not occlude together, were all single- rooted, and were replaced throughout life in alternate waves. Dentary still larger, with the little quadrate and articular bones were loosely attached. The stapes now touched the inner side of the quadrate. First sign of the mammalian jaw hinge, a ligamentous connection between the lower jaw and the squamosal bone of the skull. The occipital condyle is now two slightly separated surfaces, though not separated as far as the mammalian double condyles. Vertebral connections more mammalian, and lumbar ribs reduced. Scapula shows development of a new mammalian shoulder muscle. Ilium increased again, and all four legs fully upright, not sprawling. Tail short, as is necessary for agile quadrupedal locomotion. The whole locomotion was more agile. Number of toe bones is, intermediate between reptile number ( and mammalian (, and the "extra" toe bones were tiny. Nearly complete skeletons of these animals have been found curled up - a possible reaction to conserve heat, indicating possible endothermy? Adults and juveniles have been found together, possibly a sign of parental care. The specialization of the lumbar area (e.g. reduction of ribs) is indicative of the presence of a diaphragm, needed for higher O2 intake and homeothermy. NOTE on hearing: The eardrum had developed in the only place available for it -- the lower jaw, right near the jaw hinge, supported by a wide prong (reflected lamina) of the angular bone. These animals could now hear airborne sound, transmitted through the eardrum to two small lower jaw bones, the articular and the quadrate, which contacted the stapes in the skull, which contacted the cochlea. Rather a roundabout system and sensitive to low-frequency sound only, but better than no eardrum at all! Cynodonts developed quite loose quadrates and articulars that could vibrate freely for sound transmittal while still functioning as a jaw joint, strengthened by the mammalian jaw joint right next to it. All early mammals from the Lower Jurassic have this low-frequency ear and a double jaw joint. By the middle Jurassic, mammals lost the reptilian joint (though it still occurs briefly in embryos) and the two bones moved into the nearby middle ear, became smaller, and became much more sensitive to high-frequency sounds.

24. Cynognathus (early Triassic, 240 Ma; suspected to have existed even earlier) -- We're now at advanced cynodont level. Temporal fenestra larger. Teeth differentiating further; cheek teeth with cusps met in true occlusion for slicing up food, rate of replacement reduced, with mammalian-style tooth roots (though single roots). Dentary still larger, forming 90% of the muscle-bearing part of the lower jaw. TWO JAW JOINTS in place, mammalian and reptilian: A new bony jaw joint existed between the squamosal (skull) and the surangular bone (lower jaw), while the other jaw joint bones were reduced to a compound rod lying in a trough in the dentary, close to the middle ear. Ribs more mammalian. Scapula halfway to the mammalian condition. Limbs were held under body. There is possible evidence for fur in fossil pawprints.

25. Diademodon (early Triassic, 240 Ma; same strata as Cynognathus) -- Temporal fenestra larger still, for still stronger jaw muscles. True bony secondary palate formed exactly as in mammals, but didn't extend quite as far back. Turbinate bones possibly present in the nose (warm-blooded?). Dental changes continue: rate of tooth replacement had decreased, cheek teeth have better cusps & consistent wear facets (better occlusion). Lower jaw almost entirely dentary, with tiny articular at the hinge. Still a double jaw joint. Ribs shorten suddenly in lumbar region, probably improving diaphragm function & locomotion. Mammalian toe bones (, with closely related species still showing variable numbers.

26. Probelesodon (mid-Triassic; South America) -- Fenestra very large, still separate from eyesocket (with postorbital bar). Secondary palate longer, but still not complete. Teeth double-rooted, as in mammals. Nares separated. Second jaw joint stronger. Lumbar ribs totally lost; thoracic ribs more mammalian, vertebral connections very mammalian. Hip & femur more mammalian.

27. Probainognathus (mid-Triassic, 239-235 Ma, Argentina) -- Larger brain with various skull changes: pineal foramen ("third eye") closes, fusion of some skull plates. Cheekbone slender, low down on the side of the eye socket. Postorbital bar still there. Additional cusps on cheek teeth. Still two jaw joints. Still had cervical ribs & lumbar ribs, but they were very short. Reptilian "costal plates" on thoracic ribs mostly lost. Mammalian #toe bones.

28. Pachygenelus, Diarthrognathus (earliest Jurassic, 209 Ma) -- These are trithelodontids. Inflation of nasal cavity, establishment of Eustachian tubes between ear and pharynx, loss of postorbital bar. Alternate replacement of mostly single- rooted teeth. This group also began to develop double tooth roots -- in Pachygenelus the single root of the cheek teeth begins to split in two at the base. Pachygenelus also has mammalian tooth enamel, and mammalian tooth occlusion. Double jaw joint, with the second joint now a dentary-squamosal (instead of surangular), fully mammalian. Incipient dentary condyle. Reptilian jaw joint still present but functioning almost entirely in hearing; postdentary bones further reduced to tiny rod of bones in jaw near middle ear; probably could hear high frequencies now. More mammalian neck vertebrae for a flexible neck. Hip more mammalian, with a very mammalian iliac blade & femur. Highly mobile, mammalian-style shoulder. Probably had coupled locomotion & breathing.

29. Sinoconodon (early Jurassic, 208 Ma) -- The next known very ancient proto-mammal. Eyesocket fully mammalian now (closed medial wall). Hindbrain expanded. Permanent cheekteeth, like mammals, but the other teeth were still replaced several times. Mammalian jaw joint stronger, with large dentary condyle fitting into a distinct fossa on the squamosal. This final refinement of the joint automatically makes this animal a true "mammal". Reptilian jaw joint still present, though tiny.

Proto-mammal to Placental Mammal transition:

30. Kuehneotherium (early Jurassic, about 205 Ma) -- A slightly later proto-mammal, sometimes considered the first known pantothere (primitive placental-type mammal). Teeth and skull like a placental mammal. The three major cusps on the upper & lower molars were rotated to form interlocking shearing triangles as in the more advanced placental mammals & marsupials. Still has a double jaw joint, though.

31. Eozostrodon, Morganucodon, Haldanodon (early Jurassic, ~205 Ma) -- A group of early proto-mammals called "morganucodonts". The restructuring of the secondary palate and the floor of the braincase had continued, and was now very mammalian. Truly mammalian teeth: the cheek teeth were finally differentiated into simple premolars and more complex molars, and teeth were replaced only once. Triangular- cusped molars. Reversal of the previous trend toward reduced incisors, with lower incisors increasing to four. Tiny remnant of the reptilian jaw joint. Once thought to be ancestral to monotremes only, but now thought to be ancestral to all three groups of modern mammals -- monotremes, marsupials, and placentals.

32. Peramus (late Jurassic, about 155 Ma) -- A "eupantothere" (more advanced placental-type mammal). The closest known relative of the placentals & marsupials. Triconodont molar has with more defined cusps. This fossil is known only from teeth, but judging from closely related eupantotheres (e.g. Amphitherium) it had finally lost the reptilian jaw joint, attaing a fully mammalian three-boned middle ear with excellent high-frequency hearing. Has only 8 cheek teeth, less than other eupantotheres and close to the 7 of the first placental mammals. Also has a large talonid on its "tribosphenic" molars, almost as large as that of the first placentals -- the first development of grinding capability.

33. Endotherium (very latest Jurassic, 147 Ma) -- An advanced eupantothere. Fully tribosphenic molars with a well- developed talonid. Known only from one specimen. From Asia; recent fossil finds in Asia suggest that the tribosphenic molar evolved there.

34. Vincelestes neuquenianus (early Cretaceous, 135 Ma) -- A probably-placental mammal with some marsupial traits, known from some nice skulls. Placental-type braincase and coiled cochlea. Its intracranial arteries & veins ran in a composite monotreme/placental pattern derived from homologous extracranial vessels in the cynodonts. (Rougier et al., 1992)

35. Kennalestes and Asioryctes (late Cretaceous, Mongolia) -- Small, slender animals; eyesocket open behind; simple ring to support eardrum; primitive placental-type brain with large olfactory bulbs; basic primitive tribosphenic tooth pattern. Canine now double rooted. Still just a trace of a non-dentary bone, the coronoid, on the otherwise all-dentary jaw. "Could have given rise to nearly all subsequent placentals." says Carroll (1988).

Placental mammal to elephant transition:

36. Protungulatum (latest Cretaceous) -- Transitional between earliest placental mammals and the condylarths (primitive, small hoofed animals). These early, simple insectivore- like small mammals had one new development: their cheek teeth had grinding surfaces instead of simple, pointed cusps. They were the first mammal herbivores. All their other features are generalized and primitive -- simple plantigrade five-toed clawed feet, all teeth present (3:1:4:3) with no gaps, all limb bones present and unfused, pointy-faced, narrow small brain, eyesocket not closed.

37. Minchenella or a similar condylarth (late Paleocene) -- Known only from lower jaws. Has a distinctive broadened shelf on the third molar.

38. Phenacolophus (late Paleocene or early Eocene) -- An early embrithopod (very early, slightly elephant-like condylarths), thought to be the stem-group of all elephants.

39. Pilgrimella (early Eocene) -- An anthracobunid (early proto-elephant condylarth), with massive molar cusps aligned in two transverse ridges.

40. Unnamed species of proto-elephant (early Eocene) -- Discovered recently in Algeria. Had slightly enlarged upper incisors (the beginnings of tusks), and various tooth reductions. Still had "normal" molars instead of the strange multi-layered molars of modern elephants. Had the high forehead and pneumatized skull bones of later elephants, and was clearly a heavy-boned, slow animal. Only one meter tall.

41. Moeritherium, Numidotherium, Barytherium (early-mid Eocene) -- A group of three similar very early elephants. It is unclear which of the three came first. Pig-sized with stout legs, broad spreading feet and flat hooves. Elephantish face with the eye set far forward & a very deep jaw. Second incisors enlarged into short tusks, in upper and lower jaws; little first incisors still present; loss of some teeth. No trunk.

42. Paleomastodon, Phiomia (early Oligocene) -- The first "mastodonts", a medium-sized animals with a trunk, long lower jaws, and short upper and lower tusks. Lost first incisors and canines. Molars still have heavy rounded cusps, with enamel bands becoming irregular. Phiomia was up to eight feet tall.

43. Gomphotherium (early Miocene) -- Basically a large edition of Phiomia, with tooth enamel bands becoming very irregular. Two long rows cusps on teeth became cross- crests when worn down. Gave rise to several families of elephant- relatives that spread all over the world. From here on the elephant lineages are known to the species level.

44a. The mastodon lineage split off here, becoming more adapted to a forest browser niche, and going through Miomastodon (Miocene) and Pliomastodon (Pliocene), to Mastodon (or "Mammut", Pleistocene).

44b. Meanwhile, the elephant lineage became still larger, adapting to a savannah/steppe grazer niche:

45. Stegotetrabelodon (late Miocene) -- One of the first of the "true" elephants, but still had two long rows of cross-crests, functional premolars, and lower tusks. Other early Miocene genera show compression of the molar cusps into plates (a modern feature ), with exactly as many plates as there were cusps. Molars start erupting from front to back, actually moving forward in the jaw throughout life.

46. Primelephas (latest Miocene) -- Short lower jaw makes it look like an elephant now. Reduction & loss of premolars. Very numerous plates on the molars, now; we're now at the modern elephants' bizarre system of one enormous multi-layered molar being functional at a time, moving forward in the jaw.

47. Primelephas gomphotheroides (mid-Pliocene) -- A later species that split into three lineages, Loxodonta, Elephas, and Mammuthus:

  1. Loxodonta adaurora (5 Ma). Gave rise to the modern African elephant Loxodonta africana about 3.5 Ma.
  2. Elephas ekorensis (5 Ma), an early Asian elephant with rather primitive molars, clearly derived directly from P. gomphotheroides. Led directly to:
    • Elephas recki, which sent off one side branch, E. hydrusicus, at 3.8 Ma, and then continued changing on its own until it became E. iolensis.
    • Elephas maximus, the modern Asian elephant, clearly derived from
    • E. hysudricus. Strikingly similar to young E. hysudricus animals. Possibly a case of neoteny (in which "new" traits are simply juvenile features retained into adulthood).
  3. Mammuthus meridionalis, clearly derived from P. gomphotheroides. Spread around the northern hemisphere. In Europe, led to M. armeniacus/trogontherii, and then to M. primigenius. In North America, led to M. imperator and then M. columbi.
The Pleistocene record for elephants is very good. In general, after the earliest forms of the three modern genera appeared, they show very smooth, continuous evolution with almost half of the speciation events preserved in fossils. For instance, Carroll (1988) says: "Within the genus Elephas, species demonstrate continuous change over a period of 4.5 million years. ...the elephants provide excellent evidence of significant morphological change within species, through species within genera, and through genera within a family...."

Species-species transitions among the elephants:

  • Maglio (1973) studied Pleistocene elephants closely. Overall, Maglio showed that at least 7 of the 17 Quaternary elephant species arose through smooth anagenesis transitions from their ancestors. For example, he said that Elephas recki "can be traced through a progressive series of stages...These stages pass almost imperceptibly into each other....In the late Pleistocene a more progressive elephant appears which I retain as a distinct species, E. iolensis, only as a matter of convenience. Although as a group, material referred to E. iolensis is distinct from that of E. recki, some intermediate specimens are known, and E. iolensis seems to represent a very progressive, terminal stage in the E. recki specific lineage."
  • Maglio also documented very smooth transitions between three Eurasian mammoth species: Mammuthus meridionalis --> M. armeniacus (or M. trogontherii) --> M. primigenius.
  • Lister (1993) reanalyzed mammoth teeth and confirmed Maglio's scheme of gradual evolution in European mammoths, and found evidence for gradual transitions in the North American mammoths too.
(Most of the above text is from the link provided at the start of this post, and is the result of hard work by Kathleen Hunt, who deserves the credit. I've just extracted the relevant individual portions and assembled them into one direct fish-to-elephant sequence.)

Where are all of your intermediary forms? I'll tell you where...well, they don't exist.

*cough*. See above.

I just love how often you folks answer your own questions instead of waiting for someone else to do so. That wouldn't be quite so annoying if you didn't get the answers wrong so often.

The aggressive, arrogant ignorance of creationists never ceases to amaze me.

You know, you guys really need to go hit a library or something, and stop relying entirely on creationist screeds for your (mis)information.

So, now that it turns out that there *is* an unbroken transitional chain from fish to elephants, in just the way that evolution predicts, with small "stepwise" changes from any given step to the next, are you going to stop parroting that twaddle about how "no intermediary forms exist"?

Are you also going to admit that the existence of such a "chain" of species between fish and elephants (and countless other pairs of species) is *very* hard to explain by the creationist hypothesis? After all, as creationist icon Duane Gish said in 1988, "If creation is true, we'd expect each one of the created kinds . . . to appear abruptly and fully formed, with no indication that they had evolved from a common ancestor"

And yet, if you made a flip-book of the 50+ fossil species listed above, you'd see a clear, gradual, "movie" of a primitive fish morphing into a modern elephant, albeit with some interesting side trips along the way. And not just in general shape, either -- you'd also see each distinct bone structure being stepwise modified into its new role, you'd see cranial bones move and modify appropriately, you'd see the teeth pick up their modern features one at a time, you'd notice characteristic ridges, holes, joints, and structures slip and slide, grow or shrink in a smooth manner, and on and on. Every detail of the transitional "movie" would appropriately match the similar details of the "frames" that came before and after. You would, in short, see species transformations occurring exactly as evolution predicts, in both large form and in fine detail. And gosh, the transitional fossil "map" just "happens" to match the genetic, common-ancestral relationships implied by DNA analysis of modern species, despite the creationist claim that different "kinds" don't even share a common ancestor at all. Go figure.

"No transitional forms" my ass...

In nearly every crevo thread, creationists claim that there are no transitional fossils. Every time, evolutionists post links to the massive evidence. Then in the next thread, the creationists repeat the false claim.

It only goes to show: You can lead a creationist to knowledge, but you can't make him think.

Show me numerous creatures that live on land but still have evidence of fins (just one example).

You're laboring under a misconception. Actually, the proto-amphibians had lost most of their fins by the time they ended up "living on land" for any extended period of time. Legs (with paddle-like feet) and lungs (which originally were only *supplements* to gills) were both developed *first* in the water, *then* later put to use for land-based living.

However, here's a specimen (Acanthostega gunnari ) with clear legs and "toes" (8 of them on each limb), but a fishy finned tail:

Here's a skeletal reconstruction:

Note the fishy spine, also. Another point of interest is that the back "legs" are little more than finlike paddles, unsuitable for actual walking but fine for swimming. It could not bend at the "knee", it could only make paddling strokes.

Here's an artist's conception of Acanthostega "fleshed out":

Is it a fish or an amphibian? Hmm, looks somewhat like both doesn't it? Can you say, "transitional form"? I knew you could.

But for real fun, check out Sauripterus, an ancient lobe-finned fish:

Dennis Murphy writes:

Comparisons of these two [juvenile] specimens with a recently discovered adult specimen of Sauripterus from another Catskill Formation deposit of similar age allows us to view three stages of fin development. Lepidotrichia [fin rays] are well developed but endochondrial ossifications [internal bones] are absent in the earliest stage. Endochondrial ossification is evident in the larger juvenile, but only for those bones near the trunk. By adulthood, the fins contain both an expanded set lepidotrichia and ossified and articulating endochondrial elements [e.g., jointed bones]. These endochondrial bones include the distal (finger-like) preaxial radials well as the proximal elements (e.g., humerus, radius and ulna) seen in the older juvenile. [...] One confounding aspect of Sauripterus is the presence of eight finger-like radials in the adult fin. As with fingers, these radials are jointed and six of them articulate with the ulnare and the intermedium; both homologues of the carpus; the other two radials are conspiciously more robust and articulate directly with the radius.
In short, the specimen has unmistakable fishy fins, *with limb and finger bones inside the fins*. Furthermore, the fingers are eight in number, just like the proto-amphibians which appear later in the fossil record.

Again, can you say, "transitional"?

There should be billions of fossils showing this.

Yes, there undoubtedly are, but most of them are buried under thousands of feet of rock where they're a little hard to get to. However, we have been lucky enough to find a few scores of fossils of just the type you request from 360-400 million years ago, where Devonian formation rocks happen to be uplifted in a way that we can reach some of them, and those rocks happen to be the resting places for fish of that type, in a manner that was conducive to fossil formation (most dead creatures never get fossilized, it depends on special conditions being present).

644 posted on 05/08/2003 11:57:57 PM PDT by Ichneumon
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To: AndrewC
[Also, evolutionary programs have actually created circuits that work BETTER then human designed ones, and we can't figure out how they work. All we know is that they DO work, and many have been patented.]

Now is your opportunity to show us a few.

See post #633. The same "evolving circuits" project also came up with 3 (count 'em, 3) improvements on existing PID controller tuning algorithms, and an improved electronic circuit for PID controllers.

That's five breakthroughs in one project using evolution to produce innovations.

Hey, I thought you creationists said that wasn't possible, that evolution doesn't work?

645 posted on 05/09/2003 12:02:31 AM PDT by Ichneumon
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To: Ichneumon
Deal with it. In this case, it made a cubic function generator circuit which outperforms the best that all electronic engineers were capable of producing in all the history of electronics.

Hyperbole and a picture do not impress me, Dan. The evolved circuit has 17 transistors while the patented circuit has 9, and the electronic engineers could undoubtedly produce better control with nearly a doubling of the number of transistors. In any case, the article also says --- If (as we expect) the patent is granted, we believe that it will be the first one granted for an invention created by genetic programming.... So much for the many patents argument.

646 posted on 05/09/2003 12:13:46 AM PDT by AndrewC
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To: Ichneumon
The bible (( ot // daniel )) says ...

'evolution' would greatly increase and ---

man's depravity would supersede it !
647 posted on 05/09/2003 12:16:49 AM PDT by f.Christian (( Marching orders: comfort the afflicted // afflict the comfortable ! ! ))
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To: AmericanAge
Ever been to All of those godless atheists over there have spent a long time putting together documents trying to explain their "theory" of evolution.

They actually say "theory" not "law"? Guess they haven't growed up to "mature" evolutionists.
648 posted on 05/09/2003 12:27:17 AM PDT by jwh_Denver
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To: Ichneumon
Concerning the Cubic function circuit, this is from the patent (U.S. patent number 6,404,245).

What is needed is a compact, cubic function generator capable of operating at high frequencies and low voltages. Specifically, a circuit is required that generates a cubic function while operating at approximately 2 volts and at frequencies up to and including the gigahertz range.

Notice the word compact.

649 posted on 05/09/2003 12:31:43 AM PDT by AndrewC
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To: f.Christian
Science has't changed since it existed -- was created ... Why do you keep posting this outright lie?
650 posted on 05/09/2003 1:31:09 AM PDT by Quick1
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To: Quick1
Do you believe in alchemy ?
651 posted on 05/09/2003 1:41:50 AM PDT by f.Christian (( Marching orders: comfort the afflicted // afflict the comfortable ! ! ))
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To: f.Christian
Prove to me that science hasn't changed. I could give you a million examples where it has, bt the burden of evidence is on you, the one making the claim.
652 posted on 05/09/2003 1:53:14 AM PDT by Quick1
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To: Quick1
You can move things around all you want ... that isn't going to change them !

Have the elements -- atoms changed ?
653 posted on 05/09/2003 2:02:29 AM PDT by f.Christian (( Marching orders: comfort the afflicted // afflict the comfortable ! ! ))
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To: null and void
>>Is it?<<

For Catholics and all Protestants that I am aware of, yes.

I've seen on a Jewish website that some (maybe most) Jews believe that God created the Devil to do His will but it's antithetical to the Christian understanding of God. God is purely good and thus could not create evil.

Evil comes from turning away from God.
654 posted on 05/09/2003 2:08:39 AM PDT by CobaltBlue
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To: jwalsh07
>>Is slavery absolutely wrong morally.<<

I think so, but I recognize that others have disagreed.
655 posted on 05/09/2003 2:13:30 AM PDT by CobaltBlue
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To: f.Christian
Henry Adams taught Medieval History at Harvard. Brooks Adams was also an historian. Not exactly experts in the theory of evolution.
656 posted on 05/09/2003 2:18:51 AM PDT by CobaltBlue
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To: CobaltBlue
Often times the most wrong are the 'experts' !
657 posted on 05/09/2003 2:21:27 AM PDT by f.Christian (( Marching orders: comfort the afflicted // afflict the comfortable ! ! ))
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To: AndrewC
>> I think someone might have difficulty getting a patent for something that they cannot explain the workings, but you never know.<<

Given that patent applications are typically written by lawyers, not inventors, you might want to rethink that.

They deliberately make them as broad as possible, in order to have a patent on things they never actually thought of.
658 posted on 05/09/2003 2:26:38 AM PDT by CobaltBlue
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To: CobaltBlue
The whole purpose of the patent laws is to publish new technology that eventually will become public property --- NO SECRETS !

It has to be made known and in reality too !
659 posted on 05/09/2003 2:31:29 AM PDT by f.Christian (( Marching orders: comfort the afflicted // afflict the comfortable ! ! ))
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To: f.Christian
Henry and Brooks Adams were the sons of Charles Francis Adams, who was the son of John Quincy Adams, 6th President. John Quincy Adams was the son of John Adams, 2nd President.

If you ever read the autobiography of Henry Adams, he sort of thought he might become president one day but he really was no good at politics. So for him to sneer at other presidents as disproving the theory of evolution is just sour grapes.

I've never read Brooks Adams, but have read that he was a proto-fascist.

I didn't really enjoy reading Henry Adams, he was a bore. But it was required reading for a class I took.

His theories on the evolution of empires were rather interesting, but that was only the last few chapters and he seemed somewhat confused. I think he cribbed some of his ideas from his brother, Brooks.

By the way, I don't think you should call other people "fool." Matthew 5:22.
660 posted on 05/09/2003 2:39:59 AM PDT by CobaltBlue
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