RAZD
Member (Idle past 1597 days) Posts: 20714 From: the other end of the sidewalk Joined: 03-14-2004
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PRATT CC300, and god-of-the-gaps
Since publishing his book, The origin of species, there have been new discoveries. Advanced life forms from the Cambrian era were discovered all around the world. However the findings only served to refute Darwin’s theory as there was no evolutionary species found for the Cambrian animals. quote:
Claim CC300: Complex life forms appear suddenly in the Cambrian explosion, with no ancestral fossils. Response:
- The Cambrian explosion was the seemingly sudden appearance of a variety of complex animals about 540 million years ago (Mya), but it was not the origin of complex life. Evidence of multicellular life from about 590 and 560 Mya appears in the Doushantuo Formation in China (Chen et al. 2000, 2004), and diverse fossil forms occurred before 555 Mya (Martin et al. 2000). (The Cambrian began 543 Mya., and the Cambrian explosion is considered by many to start with the first trilobites, about 530 Mya.) Testate amoebae are known from about 750 Mya (Porter and Knoll 2000). There are tracelike fossils more than 1,200 Mya in the Stirling Range Formation of Australia (Rasmussen et al. 2002). Eukaryotes (which have relatively complex cells) may have arisen 2,700 Mya, according to fossil chemical evidence (Brocks et al. 1999). Stromatolites show evidence of microbial life 3,430 Mya (Allwood et al. 2006). Fossil microorganisms may have been found from 3,465 Mya (Schopf 1993). There is isotopic evidence of sulfur-reducing bacteria from 3,470 Mya (Shen et al. 2001) and possible evidence of microbial etching of volcanic glass from 3,480 Mya (Furnes et al. 2004).
- There are transitional fossils within the Cambrian explosion fossils. For example, there are lobopods (basically worms with legs) which are intermediate between arthropods and worms (Conway Morris 1998).
- Only some phyla appear in the Cambrian explosion. In particular, all plants postdate the Cambrian, and flowering plants, by far the dominant form of land life today, only appeared about 140 Mya (Brown 1999).
Even among animals, not all types appear in the Cambrian. Cnidarians, sponges, and probably other phyla appeared before the Cambrian. Molecular evidence shows that at least six animal phyla are Precambrian (Wang et al. 1999). Bryozoans appear first in the Ordovician. Many other soft-bodied phyla do not appear in the fossil record until much later. Although many new animal forms appeared during the Cambrian, not all did. According to one reference (Collins 1994), eleven of thirty-two metazoan phyla appear during the Cambrian, one appears Precambrian, eight after the Cambrian, and twelve have no fossil record. And that just considers phyla. Almost none of the animal groups that people think of as groups, such as mammals, reptiles, birds, insects, and spiders, appeared in the Cambrian. The fish that appeared in the Cambrian was unlike any fish alive today.
- There are some plausible explanations for why diversification may have been relatively sudden:
- The evolution of active predators in the late Precambrian likely spurred the coevolution of hard parts on other animals. These hard parts fossilize much more easily than the previous soft-bodied animals, leading to many more fossils but not necessarily more animals.
- Early complex animals may have been nearly microscopic. Apparent fossil animals smaller than 0.2 mm have been found in the Doushantuo Formation, China, forty to fifty-five million years before the Cambrian (Chen et al. 2004). Much of the early evolution could have simply been too small to see.
- The earth was just coming out of a global ice age at the beginning of the Cambrian (Hoffman 1998; Kerr 2000). A "snowball earth" before the Cambrian explosion may have hindered development of complexity or kept populations down so that fossils would be too rare to expect to find today. The more favorable environment after the snowball earth would have opened new niches for life to evolve into.
- Hox genes, which control much of an animal's basic body plan, were likely first evolving around that time. Development of these genes might have just then allowed the raw materials for body plans to diversify (Carroll 1997).
- Atmospheric oxygen may have increased at the start of the Cambrian (Canfield and Teske 1996; Logan et al. 1995; Thomas 1997).
- Planktonic grazers began producing fecal pellets that fell to the bottom of the ocean rapidly, profoundly changing the ocean state, especially its oxygenation (Logan et al. 1995).
- Unusual amounts of phosphate were deposited in shallow seas at the start of the Cambrian (Cook and Shergold 1986; Lipps and Signor 1992).
- Cambrian life was still unlike almost everything alive today. Although several phyla appear to have diverged in the Early Cambrian or before, most of the phylum-level body plans appear in the fossil record much later (Budd and Jensen 2000). Using number of cell types as a measure of complexity, we see that complexity has been increasing more or less constantly since the beginning of the Cambrian (Valentine et al. 1994).
- Major radiations of life forms have occurred at other times, too. One of the most extensive diversifications of life occurred in the Ordovician, for example (Miller 1997).
References: {25, SEE LINK for details} Further Reading:
Conway Morris, Simon. 1998. The Crucible of Creation. Oxford. Conway Morris, Simon. 2000. The Cambrian "explosion": Slow-fuse or megatonnage? Proceedings of the National Academy of Science USA 97(9): 4426-4429. (technical) Schopf, J. William. 2000. Solution to Darwin's dilemma: Discovery of the missing Precambrian record of life. Proceedings of the National Academy of Science USA 97(13): 6947-6953. Just a moment...
quote:
Solution to Darwin's dilemma: Discovery of the missing Precambrian record of life Abstract In 1859, in On the Origin of Species, Darwin broached what he regarded to be the most vexing problem facing his theory of evolutionthe lack of a rich fossil record predating the rise of shelly invertebrates that marks the beginning of the Cambrian Period of geologic time (≈550 million years ago), an inexplicable absence that could be truly urged as a valid argument against his all embracing synthesis. For more than 100 years, the missing Precambrian history of life stood out as one of the greatest unsolved mysteries in natural science. But in recent decades, understanding of life's history has changed markedly as the documented fossil record has been extended seven-fold to some 3,500 million years ago, an age more than three-quarters that of the planet itself. This long-sought solution to Darwin's dilemma was set in motion by a small vanguard of workers who blazed the trail in the 1950s and 1960s, just as their course was charted by a few pioneering pathfinders of the previous century, a history of bold pronouncements, dashed dreams, search, and final discovery. In 1950, when Ledyard Stebbins' Variation and Evolution in Plants (1) first appeared, the known history of lifethe familiar progression from spore-producing to seed-producing to flowering plants, from marine invertebrates to fish, amphibians, then reptiles, birds, and mammalsextended only to the beginning of the Cambrian Period of the Phanerozoic Eon, roughly 550 million years ago. Now, after a half-century of discoveries, life's history looks strikingly differentan immense early fossil record, unknown and assumed unknowable, has been uncovered to reveal an evolutionary progression dominated by microbes that stretches seven times farther into the geologic past than previously was known. This essay is an abbreviated history of how and by whom the known antiquity of life has been steadily extended, and of lessons learned in this still ongoing hunt for life's beginnings.
Full paper follows giving details and references Your thesis is refuted by the evidence of (a) precambrian fossils that have been found, and (b) the cambrian "explosion" occurred over millions of years and is characterized by the evolution of hard parts that fossilze easily.
Similar situations also occur throughout time including the period after the extinction of the dinosaurs 65 million years ago. This is where many modern animals, including primates, appear without any evolutionary evidence. This too is false.
quote:
THE THERAPSID--MAMMAL TRANSITIONAL SERIES Although Archaeopteryx is by far the best-known of the transitional fossils, it is not the only one, or even the best. The fossil transition from reptile to mammal is one of the most extensive and well-studied of all the transitions, and detailed series of fossils demonstrate how this transition was accomplished. It is not, therefore, surprising that the creationists do not talk much about the reptile-mammal series, and when they do, most of what they say is demonstrably untrue. The mammals are believed to have evolved from a class of Permian and Triassic reptiles known as therapsids. Taxonomically, mammals are distinguished by a number of features, the most obvious of which are hair (even such aquatic mammals as whales and dolphins still retain bristly hairs in their skin), and the presence of mammary glands which secrete milk, used to nourish the young. Neither of these structures is preserved in the fossil record, but fortunately, mammals can also be distinguished by a number of skeletal characteristics (particularly in the skull and teeth). In particular, mammals are distinguished from reptiles by a number of skeletal traits. Reptiles have a much larger number of individual bones in their skulls than do mammals. In reptiles, the teeth are all of the same shape, and although they vary slightly in size, they all have the same simple cone-shaped form. Mammals, however, possess a number of different types of teeth in their jaws, from the flat, multi-cusped molar teeth to the sharp cone-shaped canines. In reptiles, the lower jaw is made up of a number of different bones, and the jaw joint is formed between the quadrate bone in the skull and the angular bone in the jaw. In mammals, by contrast, the lower jaw is made up of a single bone, the dentary, which articulates with the squamosal bone in the skull to form the jaw joint. Reptiles also have a single bone in the middle ear, the stapes. In mammals, there are three bones in the middle ear, the malleus, incus and stapes (also known as the hammer, anvil and stirrup). At the top of the skull, reptiles have a small hole through which the pineal body, or "third eye", extends--this is absent in mammals. Finally, the reptilian skull is attached to the spine by a single point of contact, the occipital condyle. In mammals, the occipital condyle is double-faced. Paleontologists point out that the therapsids possessed many of the characteristics of both reptiles and mammals:
More at THE THERAPSID--MAMMAL TRANSITIONAL SERIES LINK including the evolution of the mammal ear ("... reptiles, as we have noted, have one bone in the middle ear and several bones in the lower jaw, and mammals have three bones in the middle ear and only one bone in the lower jaw. On the other hand, the jaw joints in the reptile are formed from different bones than they are in the mammalian skull. ..."). The evolution of mammals was well underway before 65 million years ago. We talked about the evolution of primates before in Message 109 of thread True knowledge exists in knowing that you know nothing -- which was in response to Message 89 (which you edited to delete information, however I had a pre-edit version that I posted in Message 106). Note on symbols used: └─┬─A
└─B A and B are sister clades with a common ancestor, and an equivalent cladogram would be └─┬─B
└─A while └─A
└─B shows A is a parent clade and B is a daughter (nested) clade
quote:
Palaeos Website:
Cynodontia Therapsida
│
└─Cynodontia
├─Procynosuchidae
└─┬─Galesauridae
└─Eucynodontia
├─Cynognathia
│ ├─Cynognathidae
│ └─Tritylodontidae
└─Probainognathia
├─Tritheledontidae
└─Mammaliaformes Mammalia: Overview Mammaliaformes
│
└─Mammalia
├─Australosphenida
│ ├─Ausktribosphenidae
│ └─Monotremata
└─┬─Triconodonta
└─┬─Spalacotheroidea
└─Cladotheria
├─Dryolestoidea
└─Theria
│
├─Metatheria
└─Eutheria Archonta Eutheria
├─Laurasiatheria
├?─Chiroptera
└─Euarchontaglires
├─Anagalida (incl. Glires)
└─Archonta
├─┬─Scandentia
│ └─Dermoptera
└─Primatomorpha
╞═Plesiadapiformes
└─Primates
(Note this site is interactive and you can move up and down the cladograms.) Also see the Primate Cladogram I developed to flesh out the bushiness of evolution since out last discussion and reduce the apparent linear evolution by filling some branches from Primates to Humans. That's two falsified assertions you made in your post. One you were corrected on earlier, but left the discussion when you got disturbed by the responses. Not learning from past mistakes is a sign of someone with very strong beliefs that their knowledge is correct, and who are unwilling to adapt their learning when they are shown what they believe is wrong. This is not skepticism, it is denial. Enjoy Edited by RAZD, : . Edited by RAZD, : . Edited by RAZD, : . Edited by RAZD, : ..
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