Land Mammal to Whale transition: fossils Part II

randman,I'm not digressing, this is relevant & only requires a yes or no answer, but I can't make the point unless I know your stance. I'm not about to launch into a dissertation on the merits of radiometric dating.Let me redefine the question. Do you accept standard geologic time, for example, the end of the Cretaceous was ~65 mya, the start of the Cambrian was ~540 mya, etc? That we understand & agree on the timeline is essential in any discussion regarding fossils. You are mentioning geologic ages like the Miocene, which makes no sense if the answer is "no", so I suspect the answer is a "yes", but I just want to be sure.MarkThis message has been edited by mark24, 08-13-2005 07:27 PM

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There are 10 kinds of people in this world; those that understand binary, & those that don't

randman:

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Also, both studies underscore the genuine rarity of fossilization, and the absurdity of insisting that every genera and species should be present in the fossil record.

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Define rarity. I used this example before, but it is rare for an individual to win the lottery.

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Is fossilization that rare for a species or family of species?

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If someone won the lottery thousands of times, would it still be rare?

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How about if a whole lot of people won it thousands of times?

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I challenge you to back up your claim, in terms of whale fossils. If some species of whales or families of species of whales have numerous fossils that have been found, then "rare" is a very relative term, and we could just as easily say fossilization is "common."

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Make you a deal, randman.You support your claims: 1) that every extant species of whale is well-documented in the fossil record, and 2) that 90% of all fossil species that exist have been found, and I will support my assertions.And that doesn't mean eye-rolling smilies as you cite a flattening conceptual curve that is devoid of data points.You support your claims, I'll support mine. If you don't support your claims, why should I?

I've only read this far (89 of 152) after being away a day or two so I don't which directions the thread is subsequently going to go, but here are my responses. I'm afraid I'm being dense here. Are you saying we should be able to predict the number of transitional species in the evolutionary history of a species by quantative analysis of the similarities and differences of extant species? I don't follow that chain of thought at all. Comparitive between what? The fossil records of other species? Surely the level of completeness of these parts of the fossil record are also unknown?

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No let's not say that.It might be 1%.It might be 0.0000000000000000000000000000001%.It might be less than that.Let's be honest and say we don't know what percentage fossilise - unless you can produce a figure you can back up?

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I think a reference was posted that suggests about .1 % fossilze. What this does not say is what percentage survive and are found. The only number that we have is pretty small and if we apply further loses I'd suggest we are down around .01% are available to find. What part of that is found I dunno how to calculate.This message has been edited by NosyNed, 08-13-2005 10:21 PM

You don't seem to take understand or take into account the effect of population size on gene flow.You have yet to explain in any useful way your idea of what a speciation event is.You seem to have the idea that each change that we see between extant species must mean a separate species in the ancestry.You have not considered ALL the evidence that is available to suggest that whales evolved from land animals.Only after some 200 ++ posts have you asked for any details of way Pakicetus is considered as a possible ancestor to whales. You have kept calling it rat-like and "not a whale". You do this out of ignorance of the details. Your lack of understanding of evolution makes you think (or so it seems) that the earliest beginings of a new branch of life must be obviously related to that branch 50 million years later.Other than these examples I'd say your entire contribution to these threads demonstrates you lack of knowledge of the subject. So you are actually suggesting that the occasional possibility of this occuring means it has a significant influence on the evolutionary history of the order? I'm only just aware that these cases have been observed. Do you have any details that allow you to suggest that they are common enough to be influential? I could not find any reference in the wild. It is, of course, rediculous to extrapolate from captivity for this kind of thing.I agree with you that it might be a good idea to start with a higher grouping than species or even genus. This would allow an over view examination of what has been found and then, where possible, we couild look at more details.It appears there are 14 families extant today. Since, as you point out, it might make sense that a succesful order would branch out over time I would conclude that there would be fewer families in the past.There is no hint that I am aware of that there was more than one transition of the ancestors of these families from land to water so I conclude we go from 1 example to 14 families in 50 million years.This doesn't mean that there wasn't a "hay day" for this order sometime in the past when there would have been more families but I'm not aware of any reason for thinking so.This means we need to find 14 branchs and fossils that are close to those branches to "complete" the "familiy tree" of the cetaceans. Is that what you mean?

I must have missed you actual rebuttal. Why is it that you think the molecular clock isn't possible? Of course they don't. It has been examined in some detail and, as I noted, it is reasonably successful if not as precise as the ticking of an atomic clock.What concerns do you have with it exactly?

I guess there has been some confusion as to what is being argued with. I am not scoffing at the idea of attempting to make estimates of rates of fossilization.I'm not sure what you are referring to here when you say "molecular analysis"; please clarify.What I and, I think, others have been arguing with is the idea that you can look at extant species (or families) and derive from that an estimated evolutionary pathway with enough detail to predice what forms there would have been to fossilize.Everytime this has come up you make suggestions about looking at "changes". I forget whether it is clear yet what these are but I have a picture in my mind of things like blowhole/nostril location, leg/flipper form, ear configuration, rib arrangement etc. As has been pointed out to you, but I didn't see any acknowledgement from you one, these changes do not have to happen separately creating one species at a time. In fact, I'd be surprised, given the transitional series we do have if they did occur separately.If they can happen in combination how do we decide what combinations?

There was indeed such a post - by you over in the fossilization processes thread

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http://www.madsci.org/.../archives/aug97/871343510.Ev.r.html

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Of the 100,000,000 extinct animal species, only around 100,000 species have been discovered and described. That means that only around 1/10 of 1% of all animal species that have ever lived have been discovered! (And remember that each species may be represented by hundreds of millions of individuals.)

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I don't know where they get the underlying numbers but this is a start.

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Of course, species that are larger, lived later etc. are more likely to be preserved I would guess.

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This suggests 0.1% of all species are fossilised - but in Message 126 randman says this: He's talking about 1% of individuals fossilising! That is insane - if even 0.1% of every organism that ever lived was fossilised the whole world would be a giant (fossilised) charnel house.P.S. Reading the link you originally supplied I've just realised the 0.1% is an estimate of the number of species that fossilised, survived and have been found rather than just fossilised.

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Let's consider these then shall we?alternate ToE:
I don't see why this removes the need for some transitionals, perhaps you could speculate on what the new mechanism would be and how it would remove the need for fossils as evidence.Direct ID model:
All the material I have read by the ID folks doesn't suggest that evolution doesn't happen. Nowhere in it is there anything that I have seen that would do away with the expectation of transitionals. Again perhaps you could flesh out this speculation a bit more.Special Creation Model
Does this mean that each new species is a new creation event? This was the idea that was intially put forward by geologists and biologist around 2 centuries ago. Since we have rather details transitional sequences of some species does that also mean that all of them were individual but very similar special creations too?Creationist Model
Again, there isn't much detail here. However, one interpretation of what you might be saying is the "creation week" model. This does not explain the information we do have and is strongly contradicted by that evidence so I presume you just tossed it in without thinking about it.Do you have a favourite among these and could you explain how it is better supported by the cetacean fossils we do have and how it explains all the other time sequenced fossils we do have?

Thank you. I had missed that reference earlier.I have overstated the case I'm sure. The ones that you support get, perhaps, lost in all the statements you do make.For example, I'd like your data on the collection curve. All I remember seeing was an example, ideal, dataless curve yet you have mention collection curves rather recently after having had the problem with the one you referenced pointed out several times. Perhaps I missed something there too?In addition, I have yet to see you retract or defend the 90% number. you have been given contrary numbers and there has been much discussion on that.

randman, why don't you read my message for comprehension? Your preoccupation with Pakicetus is peculiar and a red herring.You have asserted that 90% of all of the possible types of fossils have been found. I have given you a link to a complete lising of the fossil species of archaeocetus, a suborder which is considered to be ancestral to extant cetans. You argue that the (hypothetical) collector's curve shows that most of the fossils have been found and you think there is an absence of "transitional" fossils.Enough rhetoric, let's see some hard data and analysis. Do the analysis of archaeocetans and see if it fits the collector's curve. Or are you going to run away from real data?

I rather like all of your post above this part. It helps to clarify where you are in the discussion now. Some of us are still responding to earlier posts that you seem to have explictly dropped.However, this paragraph is showing a particular strong misunderstanding of what would be expected by evolutionary theory.There is no reason to think that there would be many indiviuduals, species or families of the intial transition from land to water. Basilosaurus is a branch that is some millions of generations after the new niche as been entered.It has been explained to you several times that the transition itself would not expected to be in such a large population. And for that initial transition we seem to have several fossils already.

It is interesting that there are 7 families represented here. I haven't had time to look at the time frames involved but it is clear it covers the first 10 million years at least.Since we have 14 families extant now finding 7 from the early days before as much branching might have happened suggests we do have a more complete series of fossils than I thought.Perhaps the whole arguement for almost 500 posts has been based on a general lack of knowledge about just how much fossil evidence there is? How amusing.

And I don't recall you ever saying why you don't. Since the connection is made on some specific details of the bones I would expect you to comment on the form of those bones are why they are not similar to cetaceans.In addtion, 2 or 3 of the scenerios you painted (directed ID etc.) are NOT in anyway contrary to there being such transitionals as Pakicetus I don't see why you are bothering to argue about it. Odd, I keep missing the analysis. Perhaps you can link to the post or repost it? You have been told over and over what happened to the ones we don't see. You apparently don't bother to read that.