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Author | Topic: Land Mammal to Whale transition: fossils | |||||||||||||||||||||||||||
robinrohan Inactive Member |
In fact I am thinking specifically in terms of species, and not "kinds" on this thread, and robin offers no evidence that there is no such thing as species and speciation There is in a sense evidence of "speciation," but only in a sense. What you treat with contempt as an "early whale" we could very easily call something else, such as a "hippo in the water" or something. There is not a strict dividing line between species. If you thnk there is, you are thinking in terms of kinds.
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Yaro Member (Idle past 6527 days) Posts: 1797 Joined: |
So, this is randman's way of debating. Complaining that the other posters shot down his points and riddled his arguments full of holes. Then tatling to the mods asking them to sensure his oponents.
Pretty crafty, you should be a lawyer randman. ABE: It's also interesting to note that his "filed" complaints are things delt with early on in the thread. Not to mention they are a gross missrepresentation of my possition as anyone who was following along will see. This message has been edited by Yaro, 08-05-2005 06:58 PM
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Melchior Inactive Member |
Still, you can easily ask the same question by formulating it:
"Do we find a sufficient number of intermediate inviduals, as fosils, to establish the link between land mammals and whales based on the fosil record alone? How does this specific 'lineage' compare to other well established cases?"
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Omnivorous Member Posts: 3992 From: Adirondackia Joined: Member Rating: 7.5 |
Thanks for calling for those numbers, Nosy: I've been fishing for a few of my own, since it first struck me back in Message 41 that 1) events are not fossilized, and 2) we have no criteria for determining species (defined via reproductive compatibility) in the fossil records.
Then I started to wonder about randman's claims about the flattening curve of fossil discoveries. My "www" intuitive alert went off, albeit a little late. I follow fossil discoveries as closely as time allows, and it seems to me that the discovery rate is definitely accelerating: hominid discoveries in the past couple of decades have occurred with increasing frequency, and the finds from South America and China are staggering in both number and quality. At first I tried to do my own calculations: how many species to a measured plot of S. American rain forest, how many fossil species found in a measured fossil bed grid, etc., hoping to generate some approximation of how many species might plausibly have lived in a particular past era vs. how many have been found...well, let's just say I decided not to pull numbers out of randman's hat. Here is a useful characterization by Rick Cheel, Professor of Earth Sciences at Brock University in Canada (emphasis added):
quote: Given that the fossil record is extremely sparse when compared to the number of species likely to have existed, the odds of finding a species and the immediately ancestral species and the immediately descended species are astronomical. Of course, that is supposing we could determine those relationships. Finally, for me, the most delectable irony is the reminder that we have not yet found every living species, or even a preponderance of them. This message has been edited by Omnivorous, 08-05-2005 09:07 PM
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randman  Suspended Member (Idle past 4930 days) Posts: 6367 Joined: |
Please define "kinds" and why you think the concept of "species" and "speciation" does not exist.
Are mammals not grouped together into species? groups that can and do interbreed? Obviously they are, and hence you are wrong. The blurriness with some species or subspecies that occurs is an issue, but it's not germane to this thread because we can eliminate all such blurriness by defining species, for the context of this thread, more broadly as individuals that can interbreed and produce fertile offspring. That may actually make a few iffy "species" such as the pseudorca and bottlenosed dolphin the same "species" despite being classified as different genera, but it suffices here. It is a clear line of demarcation, something real, contrary to what you claim, and something we see in nature today. It is an observable. So how many such speciation events where groups that can interbreed with one another and not with other groups have occurred or would need to occur to transition a land mammal to a whale? Please answer the question.
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randman  Suspended Member (Idle past 4930 days) Posts: 6367 Joined: |
That's a fallacious argument on 2 points.
First, some species don't fossilze well, such as sharks. Basically, we tend to have sharks' teeth, but no bones because they have cartilage instead of bones. So in terms of this discussion, we need to be talking about land mammals, semo-aquatic and aquatic mammals and most importantly whales. The fact some worm or plant or bacteria is not fossilized, or we have not discovered them is not germane to the discussion. The second point is that "species" defined more narrowly is probably not a good bench-mark. We need to stick to a broader definition of species, basically groups that could interbreed, and the reason is that we are more likely, contrary to what you guys claim, be able to estimate from fossils the broader term than we can define species as we do more narrowly. To apply these points, we should talk of how many mammal species there are. Next, we should be careful not to count species that share near identical bone structures but are counted as separate species for other reasons. This should be obvious since we are examining fossils, and if we looked at identical bones, we would assume 2 different species. So what's the number of "species" today for cetaceans, and for mammals in general, and what is the total number of mammals discovered in the fossil record and living today. That would be a good start, if anyone knows. Then, we could discuss fossilization rates.
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Omnivorous Member Posts: 3992 From: Adirondackia Joined: Member Rating: 7.5 |
Nope, not fallacious. You are correct that it could be more precise, and I'll look into those numbers, but basically...
*whooosh* that's the sound of hypersonic goal posts passing by...
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jar Member (Idle past 425 days) Posts: 34026 From: Texas!! Joined: |
Please define "kinds" There are three kind, plant kind, animal kind and other kind. Aslan is not a Tame Lion
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randman  Suspended Member (Idle past 4930 days) Posts: 6367 Joined: |
Given that the fossil record is extremely sparse when compared to the number of species likely to have existed, the odds of finding a species and the immediately ancestral species and the immediately descended species are astronomical. OK. So the claim is we don't see speciation events documented because the fossil record is too incomplete. Thank you for admitting that we don't see such events documented in the fossil record. As it is a secondary claim, we can move on the main points, which are numbers of transitional forms needed or predicted and how many we should expect to find in the fossil record. On the speciation event, if someone knows of any speciation event being documented in the fossil record, that would be of interest because we could have some more data to consider, in terms of why we don't see the species before and after a species appears. Anyone know of any documented cases of speciation?
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Omnivorous Member Posts: 3992 From: Adirondackia Joined: Member Rating: 7.5 |
randman writes:
quote: Nope. Nice obscurantist effort, though: my assertion is that events do not fossilize. The observation was that the fuzzy depiction of one you put forth was 1) astronomically unlikely to be found in the short time we have been digging up fossils, and 2) unverifiable. That is why you defined it that way.
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randman  Suspended Member (Idle past 4930 days) Posts: 6367 Joined: |
Are you saying numbers here including bacteria, non-vertibrates, etc,...are relevant and somehow I am moving the goal-posts?
Please tell me you don't honestly believe that.
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Omnivorous Member Posts: 3992 From: Adirondackia Joined: Member Rating: 7.5 |
randman writes:
quote: Look randman, let's be frank...well, I'll be frank, you be you. You toss out numbers like a deli ticket wheel, and ignore calls to back them up: '1000 speciation events'...'90% of fossil forms found'...etc. So, why, of course I believe that: the figures relate to a global average. I'm sure your incredulity springs from the same arithmetic I've done: the figures I presented suggest the half dozen or so ancestral species are about what we should have found so far, given that global average. Your tactics are those of a losing chess player: complicate the position whenever possible, and flee simplifying exchanges. I'm happy to dig for more specifically applicable numbers, partly because it will be a genuine learning experience, partly because I suspect it will make my assertion even stronger...but not because I think it will have any impact on you. Your assertions form one amalgamated appeal to consequences--the consequences to your beliefs. The finer grained data--number of extant aquatic species, the number of aquatic fossils found, the surface area of the earth scrutinized to date, the likelihood of salt-sea fossilization--promise to weigh on my side of the scale, not yours. We'll see--though I am sure your arms will wave when I post them. Nite.
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MangyTiger Member (Idle past 6384 days) Posts: 989 From: Leicester, UK Joined: |
Just caught up with this thread (a lot of reading )
If you say because fossilization is such a rare event, then where is the study indicating the degree of rarity given millions and millions of years. I would say whether fossilisation of an individual occurs is essentially unpredictable. How many individuals are likely to be fossilised will be affected by things like population size and habitat but even so I don't know if anyone could quantify it. Even if they could the question of whether we ever find the fossil is somewhat beyond our control (see below).
Let's say we can find 50% of the current species in fossilized remains, then would it not be reasonable to expect to find 50% of the fossilized transitional species? Never hear of erosion? subduction? the fact that around two thirds of the surface of the planet isn't easily available for us to examine? Once a species has gone extinct all the fossils that will ever exist for it have been created. From then on it is a matter of luck how many will survive long enough for us to find them - the number available is only going down with time. We might never find any of them.
accorind to ToE, so there should be thousands of transitional forms
I have no biological education beyond grammar school (high school to the ex-colonials ) so I am open to correction from a professional but I don't think this is true. The Theory Of Evolution doesn't say anything about how many fossils will be found. It may say that there will be many transitional forms (every individual is both a transitional and a member of a fully formed species) but it doesn't say anything about how many will fossilise, when in time fossils will be formed and whether we actually find them before they are destroyed. Oops! Wrong Planet
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randman  Suspended Member (Idle past 4930 days) Posts: 6367 Joined: |
Ned, imo, the evos here are the ones that should be trying to back up their claims of fossil rarity, not me, but here it goes.
How many kinds of cetaceans are there? Lots! Over 70 species of whales, dolphins, and porpoises populate the world's oceans. http://nmml.afsc.noaa.gov/...cetaceans/groupsofcetaceans.htm So this site says over 70. I've heard claims up to 81 species. Apparently, some species can interbreed and do so in the wild so maybe something like 75 is a good estimate. However, note how much of what is printed on the Net is not factual so we have to take everything with a grain of salt. For instance,
Pakicetus, shown above right, is a Middle Eocene archaeocete from the Kuldana Formation of Pakistan; it is currently the earliest known well-preserved cetacean, and the archaeocete features are clearly visible in this replica skull from UCMP's collections. Pakicetus is so far known only from its skull, but recent finds in Pakistan have produced other whale species that show very primitive characters in both the skull and the rest of the skeleton. These animals had relatively well developed limbs, but were aquatic. Cetaceans Obviously, this is wrong since Pakicetus is not aquatic, but it's interesting how once a claim is made, as it was initially, evolutionists tend to maintain some semblance of that claim, even if wrong, if the claim helps verify ToE. Just an aside. But taken with a grain of salt.
By the Miocene, whales of both lineages are relatively common fossils in many marine deposits. A number of modern-day families of both toothed and baleen whales are known to have evolved by the late Miocene. These include the baleen whale families Balaenopteridae (rorqual whales, including the blue whale) and Balaenidae (right whales), and the toothed whale families Delphinidae (dolphins and killer whales), Physeteridae (sperm whales), Monodontidae (belugas and narwhals), Phocaenidae (porpoises), and Ziphiidae (beaked whales). Shown at right is the partial skull of a porpoise from the Miocene-age Monterey Formation, exposed at Duxbury Reef in Marin County, northern California. Cetaceans It appears there is an abundance of whale fossils, "relatively common in many marine deposits". In fact, there is not a whale family that is not well-represented, and considering we see interbreeding between sub-families, according to one classification, with pseudorcas and bottlenosed dolphins, we really have a lot of fossils of the existing whale population "species" as broadly defined. In fact, we have every family represented, if not every species. So based on this, I would expect every family of the theorized transitional forms to be found in the fossil record. Now, the question is how many orders, families, genera and species should we expect to have evolved during the 15-20 million year period of the theorized land mammal to whale evolution? Considering these different branches undoubtedly would spin off into dead-ends or less whale-like and non-aquatic animals, I would expect a fairly massive number of transitionals to be found, and that we would see dozens of groups of species, besides cetaceans, that developed and went extinct in the fossil record or perhaps continued on. There are so many differences between whales and land mammals that as a transitional form developed, I would expect it to likewise develop dozens if not hundreds of species over time. I would expect there then to be more than a handful of fossilized species that could be considered transitional, and based on the numbers of current whales represented in fossil finds, I would expect most species and genera, and every family, every order, etc,..to be discovered. I would expect every family to be discovered in the fossil record since we see every whale family fossilized that is current today. This message has been edited by randman, 08-05-2005 11:41 PM
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MangyTiger Member (Idle past 6384 days) Posts: 989 From: Leicester, UK Joined: |
quote: I think you're reading this wrong. Pakicetus has always known to be terrestial even when all we had to go on was the skull because it was found with unambiguously terrestial organisms (see this EvoWiki article). The line "These animals had relatively well developed limbs, but were aquatic." refers to the recent finds of other species mentioned in the preceding sentence. I suspect they are talking about Rodhocetus amongst others. Oops! Wrong Planet
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