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Author | Topic: Does evidence of transitional forms exist ? (Hominid and other) | |||||||||||||||||||||||
mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
I'm being a bit lazy here, listing examples I have already given in other posts.
Invertebrate transitionals :
http://www.gcssepm.org/special/cuffey_04.htm Consider the brachiopod Eocoelia from the Lower Silurian of Great Britain (Ziegler, 1966). We find two species both classified as Eocoelia based on the details of internal morphology. However, the shells of the older species are coarsely ribbed whereas the shells of the younger species are smooth (Ziegler, 1966). If we examine samples collected from geochronologically intermediate positions, we find a succession of Eocoelia that progressively reduced and ultimately lost the ribs (Ziegler, 1966). This morphologic progression can be illustrated both qualitatively with specimen illustrations and quantitatively by measuring rib strength and plotting the data as a series of histograms in stratigraphic order (Ziegler, 1966). Such sequences are the preserved remains of temporally successive populations of organisms that morphologically changed from one species into another. All of these intermediate forms thus qualifies as transitional fossils. The only logical conclusion is that such successive populations were produced by normal reproductive processes. That is descent with modification (Cuffey, 1984, p. 266-269).Research has provided many examples of successive species and genera (and in some cases families) linking major higher taxa of order or class rank (Cuffey, 1984, p. 266). For example, within Phylum Mollusca, transitional fossils have been found between [1] Class Monoplacophora and Subclass Nautiloidea (Pojeta, 1980; Runnegar & Pojeta, 1974), [2] Class Monoplacophora and Class Rostroconchia (Pojeta, 1980; Runnegar & Pojeta, 1974; Pojeta & Runnegar, 1976; Runnegar, 1978), [ 3] Class Rostroconchia and Class Pelecypoda (Pojeta, 1980; Runnegar & Pojeta, 1974; Pojeta & Runnegar, 1976; Pojeta, 1978), [4] Class Rostroconchia and Class Scaphopoda (Pojeta, 1980; Runnegar & Pojeta, 1974; Pojeta & Runnegar, 1976, 1979) , [5] Subclass Bactritoidea and Subclass Ammonoidea (Erben, 1966). http://www.geo.ucalgary.ca/~macrae/talk_origins.html#trilobites Showing Trilobite transitionals. Pikaia gracilens (Science & Earth History, Arthur N Strahler, 1999, p405)
http://www.asa3.org/ASA/topics/Evolution/PSCF12-97Miller.html The Cambrian lobopods occupy a transitional morphological position between several living phyla. The oldest known lobopod from the Early Cambrian is Xenusion. This organism bears similarities to both palaeoscolecid worms and to living onychophorans and tardigrads. Furthermore, lobo-pods also have morphological features in common with the arthropods, particularly with peculiar Cambrian forms such as Opabinia and Anomalocaris. Recent redescription of Opabinia has also disclosed the presence of lobopod limbs strongly suggesting a lobopod to arthropod transition. The discovery of a Cambrian gill-bearing lobopod reinforces this conclusion. These forms fall nicely into a transitional position between extant phyla.Another very important group of Early Cambrian fossils is represented by a wide variety of tiny cap-shaped and scalelike skeletal elements. It is now known that many of these belonged to slug-like animals that bore these hollow mineralized structures like a dermal armor. Two well-known, and well-preserved, examples of this group of organisms are Wiwaxia and Halkieria. Called the Machaeridia or the Coelosceritophora, these organisms are mosaics of phylum-level characteristics, and their taxonomic affinity is a matter of present debate. A strong case can be made for the assignment of at least some of these taxa to the Mollusca. However, a relationship to the polychaete annelid worms is also strongly suggested by some workers, as with Wiwaxia. The taxonomic confusion associated with these scale-bearing slug-like animals, and with the lobopods, is consistent with their stratigraphic position at the base of the Cambrian metazoan radiation. http://www.natureasia.com/get.pl5/abstracts/issue991202/abstract991202_518.shtml An early Cambrian craniate-like chordateJun-Yuan Chen, Di-Ying Huang and Chia-Wei Li Since the identification of the Lower Cambrian Yunnanozoon as a chordate in 1995, large numbers of complete specimens of soft-bodied chordates from the Lower Cambrian Maotianshan Shale in central Yunnan (southern China) have been recovered. Here we describe a recently discovered craniate-like chordate, Haikouella lanceolata, from 305 fossil specimens in Haikou near Kunming. This 530 million-year-old (Myr) fish-like animal resembles the contemporaneous Yunnanozoon from the Chengjiang fauna (about 35km southeast of Haikou) in several anatomic features. But Haikouella also has several additional anatomic features: a heart, ventral and dorsal aorta, an anterior branchial arterial, gill filaments, a caudal projection, a neural cord with a relatively large brain, a head with possible lateral eyes, and a ventrally situated buccal cavity with short tentacles. These findings indicate that Haikouella probably represents a very early craniate-like chordate that lived near the beginning of the Cambrian period during the main burst of the Cambrian explosion. These findings will add to the debate on the evolutionary transition from invertebrate to vertebrate. Lets take the evolution of the horse, from: Hyracotherium (Eohippus), to Orohippus, to Epihippus, to Mesohippus, to Miohippus, to Parahippus, to Merychippus, to Pliohippus, to Modern Horse. Why is this sequence inferred? In all cases, a progressive reduction in side toe functionality appears, with increased emphasis on the middle toe. The side toes become increasingly vestigial, as the middle toe becomes more prominent, ending up as the hoof. Not enough? A similar progression is seen in size, skull shape, & teeth forms.Still not enough? The side toes on modern horses are represented today as splints at the back of the shins. The process can be seen in the flick book of horse evolution. If this sequence never occurred, why do the side toes appear in horse embryos? Also, they are present occasionally in adult horses, exactly where the fossil record predicted they would be, replacing the splints. (Science & Earth History. Arthur N. Strahler 1999). And, our old friend, Archaeopteryx. Present In Dinosaurs But Not In Birds: Pubic peduncle, long bony tail, abdominal ribs. Present In Birds But Not In Dinosaurs : Pygostyle, bony sternum, furcula (wishbone), hypotarsus, feathers. Present In Archaeopteryx : All of the above. The problem is, creationists hear something that they like, "there are no transitional fossils" & stop right there. No more thinking or research is required. There are new transitional fossils being discovered with regularity, I'm afraid. ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
quote: Joz, I don't remeber that specifically, but dinosaurs being found with their stomach contents are nothing new.
http://exn.ca/Dinosaurs/LifeStyles.cfm"Dentition can usually determine if dinosaurs were herbivorous or carnivorous. But to get any more specific, evidence of stomach contents are important. Pine needles and twigs have been found inside the fossils of duckbilled dinosaurs, and small mammals and lizards have been found in the stomach cavities of Coelurosaurs." http://www.paleodirect.com/pliopleo1.htm (Pliosaurs)We can learn about what they ate from the fossils. Occasionally stomach contents are found with well-preserved specimens, showing that some at least fed on belemnites and ammonites. http://www.fossilking.com/earlyfossils.html#(Platecarpus) Stomach Contents:A Shovel-nosed Guitar Fish (similiar to shark), 3.5' long. - and - The skull of an Arambourg, originally 6' long. The most complete discovery of this species was destroyed in WW II. The list goes on & on.......... Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
Fish Transitionals:
http://www.sciencenews.org/sn_arc99/11_6_99/fob1.htm Until recently, fish appeared suddenly in the fossil record. The earliest known chordates, in which resides the vertebrate sub-phylum, were amphioxus like organisms. Lacking backbones, but possessing notochords, these were represented by pikaia, Yunnanozoon lividum, Haikouella lanceolata. The "intermediate" between chordates & true vertebrates (Of which fish are the earliest representatives)was missing. Until now. Two species, Haikouichthys, & Myllokunmingia have been found in chinese lower cambrian rocks. "Both the Chinese specimens have a zigzag arrangement of segmented musclesthe same type of pattern seen in fish today, reports Degan Shu of Northwest University in Xi'an, China, and his colleagues. The fossils, named Myllokunmingia and Haikouichthys, also have a more complex arrangement of gills than the simple slits used by amphioxus, according to the team's report in the Nov. 4 Nature." "Although the ancient Chinese animals qualify as vertebrates, they lack the bony skeleton and teeth seen in most, but not all, members of this subphylum today. Instead, these early jawless fish appear to have had skulls and other skeletal structures made of cartilage, says Simon Conway Morris of the University of Cambridge in England, who collaborated with the Chinese team." Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
quote: How would be being between one form & another too different? ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
quote: What do transitionals have to do with apes, per se? Can you explain why horse embryos have 3 toes, but the adult horse rarely does (the splints have sidetoes)? A true vestigial trait. Curiously, the fossil record shows a slow reduction in toes/ toe functionality in horses. Can you explain this remarkable corroboration? Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
Science & Earth History, Strahler, 1999 p443. See also polydactyly by atavism . Gould, 1983, pp. 177-179.
http://www.cs.colorado.edu/~lindsay/creation/horse_growth.html Foetal Growth Of A Horse Foot.
Mark ------------------Occam's razor is not for shaving with. [This message has been edited by mark24, 02-19-2002] [This message has been edited by mark24, 02-19-2002]
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
quote: It wasn't disproven, it has been revised however. Hypohippus, Anchitherium, Archeohippus, Hippidium, & Hipparion (& related genera) are no longer inferred in the direct line of Hyracotherium-Equus lineage. Why not try to explain the vestigial toes in ALL modern horse embryos, & occasionally, modern horses? Mark
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
[QUOTE]Originally posted by redstang281:
[b] Why not try to explain the vestigial toes in ALL modern horse embryos, & occasionally, modern horses? This website can answer your question.
http://www.answersingenesis.org/docs/4117.asp [/QUOTE] Can you explain the vestigial, atavistic traits found on some horses that I outline in messages 16 & 20? I couldn’t find anything that answered my question in AiG, could you elaborate?
quote: Redstang, That's pretty much what I said. What your cites don't say is that there still exists a straight lineage from hyracotherium to modern horses. What has been revised, is the thought that ALL "proto" horse fossils" were part of that DIRECT lineage. Picture a tree, pick a twig at the top. Now trace a line from the bottom to the top. That there are branches simply means speciation has occurred, any branch off of your line means that any organism representing that split is no longer in the direct line of ancestors for your twig (modern horse). Really, you would expect this of evolution, no? All that has been shown is that there is a phylogenetic tree rather than a straight line. Hang on? A biblical reference to phylogenetic tree? This tree is actually being used as a REASON to falsify horse evolution? To accept & use a phylogenetic tree to falsify something requires the acceptance of the said tree (small point, your quote is wrong, a usual phylogenetic net isn’t produced, it’s a tree). Do you accept the morphological phylogeny of horses, as your cite described? It seems in falsifying this aspect of evolution, you have accepted it. Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
TC,
Sorry if I missed your earlier answer, the structures are clearly toes, they even have separate bones. Why would anything need to hold the leg in place? We don't have anything to stop our shins from "drifting off". Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
TC,
They are analogous to your own 2nd & 4th toes. Mark ------------------Occam's razor is not for shaving with.
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
TC,
This doesn't explain the side toes in some ADULT horses, let alone ALL emryos. It isn't the splints I'm saying are vestigial atavisms, it is the side toes. They are not extant in all horses, so serve no function, they are truly vestigial. Mark ------------------Occam's razor is not for shaving with. [This message has been edited by mark24, 03-14-2002]
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
ex libres,
I was simply pointing out that to use Archy.. as an example of a transitional form, to make the case for evolution occuring, falls apart when you see what this BIRD truly represents. A BIRD. Not a part reptile part bird. Nonsense. Archy was originally classified as a reptile. Let's assume it still was, you would claim that it isn't a transitional because it was classified as a reptile, wouldn't you? It has to be classified as one or the other. The FACT is that is possesses reptilian features that no other bird has, & bird features that no reptile has. It is a classic transitional. How many birds do you know have a long bony tail, abdominal ribs, & a pubic peduncle a la reptiles, among other traits? Mark
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
ex libre,
Please address the point I raised. Archy has traits associated with reptiles as well as birds. A fossil possessing traits normally associated with different taxa is what is expected of a transitional, it is an evolutionary prediction borne out. Mark [This message has been edited by mark24, 03-01-2004]
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
ex libres,
Explain to me how Archy came to be. (A) Did a dinosaur such as a raptor lay an egg and out popped Archy? or (B)Did Archy develop the wings over a long period of time? If (A), then punctuated equalibrium is your game; a theory not even accepted by most evolutionists. If (B) then wouldn't One, partly formed wings be a disadvantage in that they would be useless until fully formed and two, does evolution cause changes in such a way that predicts future forms as being advantages. I'd like to clear up one major misconception. PE is NOT saltational. PE isn't overwhelmingly accepted because evolutionary rate change in lineages hasn't been explicitly associated with cladogenesis as per Eldredge & Gould's theory. However, anagenetic rate changes are well documented. So essentially a "weak" form of PE is universally accepted by scientists. Pure phyletic gradualism has been out of the window for some time, & saltationalism never really was accepted at all. Current accepted theory states that the most recent common ancestor ancestor to birds & reptiles are therapods. Essentially speciation would have separated the therapod lineage from the lineage that was to become birds. Feathers may well have already have existed given non-avian dinosaurs being in posession of them. For whatever reason the forelimbs of the proto-birds were exaptations allowing for some sort of gliding from trees, accelerated propulsion on the ground, or increased manoeuvrability on the ground. Increasing these traits in no way means the organisms involved had to run about with "half a wing", or a useless limb that could by definition not have been adaptively selected for flight. The limbs were plausibly & reasonably vital to the animals at all stages through the history of the evolution of flight.
These are the questions you should ask yourself. A watermelon is 80% water, a jellyfish is 80% water, and a cloud is 80% water. There is only 20% difference. Do they have a common ancestor? Clearly water content is not a synapomorphy.
why haven't we found anything between the two as we would expect if it were a true transitional form?.....Where are the transitionals of plants and insects? Classic creationist arguments from ignorance. There ARE transitional plants, & there ARE transitional insects. But here is not the place to discuss them, & let's face it, you'll only want the transitionals either side of the fossils, anyway (like you are doing with Archy).
Why would only a few speicies experiance evolutionary change while others seem to vertually identical to their prehistoric ancestors. The Nautilus is one example, the Cealocanth (not sure of spelling)is another, as well as bacteria, amphibians, and insects found in amber. There isn't a single species that has survived since the K-T boundary, not one. That the body plans of their constituent clades should survive should be no great surprise, but then we are talkning about much larger groups of species, genera, families, etc. Your argument is the same as expressing surprise that tetrapods as a whole have survived since the Devonian, or that unicellularity still exists, or that there are still such things as arthropods, or that the continued existence bryozoans somehow presents a problem for evolution. And so it goes on..... A different question is to ask why species appear to exhibit stasis for periods of time, & then fairly rapid change occurs giving rise to other similar but morphologically different species. The potential answers are many. That environments are stable for periods of time & then exhibit rapid succession themselves. I can't for the life of me remember where I read this, but there is a study that supports this. There is a fairly rapid faunal turnover followed by ecological stasis, linked to climatic variation. The organisms simply adapt to their environments within the limits of their historical constraints, or become extinct. The survivors radiate & fill the exposed niches. That species habitat track is another, or live in environments that are shielded from major & rapid change, like the deep sea environment of Latimeria chalumnae. Interestingly, many Cenozoic coelacanths are freshwater fish, it shouldn't be a surprise then that the surving members fall into this change resistent environment. In essence these organisms are optimised & any variation is penalised, this is called stabilising selection. Rapid change tends only to be recorded in clades in which there is a good fossil record, siliceous, & calcium carbonate shelled critters spring to mind. The radiolarians, coccolithophores, foraminifera, molluscs & brachiopods, for example. The chances of seeing accelerated gradualism in rarely fossilised clades approaches zero. In any case all of this is simply a diversion. The FACT remains that Archaeopteryx lithographica possessed traits that are only found in reptiles, & in modern birds. It is by definition a transitional. Please directly address this FACT in your next post rather than a succession of diversions that skirt around the edge of it. Mark "Physical Reality of Matchette’s EVOLUTIONARY zero-atom-unit in a transcendental c/e illusion" - Brad McFall
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mark24 Member (Idle past 5223 days) Posts: 3857 From: UK Joined: |
pop,
Perhaps if you define "transitional fossil" as expected by the ToE, you'll see your problem. Mark There are 10 kinds of people in this world; those that understand binary, & those that don't
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