fossilization processes

The science here is called taphonomy. Google that and search here and you will find a lot.Generally, I think the "mini-catastrophes" is correct. Even bones don't last long in the open so it requires something special to preserve something long enough to fossilize.

Randman, you gave specific quantities for the numbers of fossils that should be found.You have been asked to show your development of those numbers or retract them.Do you have time yet?

Let's see if we can make some estimates on how complete the fossil record might be:from : Canadian Biodiversty: SpeciesThere are currently about 4,500 mammal species alive today.Let's assume a species "lives" for an average of 5 Myrs (I read it somewhere -pick another number if you don't like it).That suggests that since the end of the cretaceous and the "age of mammals" starting we should have had about (65/5) * 4500 = 58,000 separate mammal species. Subtract 4500 for the current ones gives 53,500 extinct species.Now the question is how many have we found?That is a harder answer to track down. You suggested the answer should be 90% or 48,000. I suggest that you are off by about an order of magnitude. I'm not at all sure of how to prove that though.

from: http://www.madsci.org/.../archives/aug97/871343510.Ev.r.html I don't know where they get the underlying numbers but this is a start.Of course, species that are larger, lived later etc. are more likely to be preserved I would guess.

I did? In what why? All I am working with is that there were very different forms of mammals around at different times in the past? I didn't say how they got there or changed in the next snapshot. Do you have a problem with that? That is strongly biased in two ways:
1) more recent species will have some recent remains thus biasing the sample to show a larger percentage.
2) it may be that NONE of the samples are fossils that could be expected to survive even centuries talk about millionso of years thus biasing the answer to very low percentage of preservation.Since it is clear that there have been totally different forms of life at different times we must use an estimating technique that allows us to consider the time frames and conditions. now you are guessing and working with families. Does that mean your previously supplied numbers are in the dust bin?I agree that the whole thing is interesting. We should continue to try to dig up what we can find.This message has been edited by NosyNed, 08-07-2005 10:42 PM

You are making what may be unwarrented assumptions about preservation rates here. The relative rate for aquatic and semi aquatic may be high but the rate for dry land based forms is dammed near zero. This means the aquatic rate doesn't have to be that high.Simply stating that is is high means zip. We need to dig a bit more to see what evidence there is.I await your reasoning for why the 0.1 % number is not a good place to start working.This message has been edited by NosyNed, 08-07-2005 10:56 PM

LOL, , of course! Do you miss the whole point of the collecter's curve. We are sampling something with an unknown number of different items. We are attempting to estimate the nature of the population from that.There have been, so far, a couple of ways of getting there presented here. One is the collector's curve and the other is based on assuming biological diversity something like todays.The collector's curve has yet to be shown to be applied to any fossils that we have discussed yet. You have just shown the basic concept.Someone already noted that for dinosaur's the collector's curve says we are still a long way from finding most of the samples. Since almost all whale-thingies have been found in the last decade or two it appears we are also a long way from the flat part of that curve too. But then we don't have numbers so we are just guessing on that. For most people it isn't very interesting -- they are much more interested in finding the next exciting specimen than worrying about how many their are left.You have been making your own assumptions about how many species there "should be" from post 1. Why do you object to trying to come to as reasonable estimate as possible instead of just guessing -- which is all you have been doing so far? Got a better way of arriving somewhere? I don't understand this. Care to explain more fully? You didn't answer the pair of my points just sort of this one.As I noted the very most recent remains will almost all not be "fossils" at all. So there are none that are recent. But we then have to define what the heck we mean by "fossil" for that to make sense.

I'm sorry I was a bit unclear. There are two different things being discussed. The estimates from biodiversity are not numbers to be put in to the collector's curve. They are separate ways of attempting to arrive at an estimate of the number of species left to be found. I have, based on your rough idea of what each step would be agreed that something like 1,000's isn't too bad a number.However, any such estimate is very dodgey at best. It is entirely possible that two or 3 changes occured together in one population so it isn't clear if we call those 1 step (only one 'speciation') or 3.Some of the changes are simply "more of". That is, when a limb is being used as a paddle it may become more paddle-like in very, very small steps. These may spread through a population rapidly or slowly. The population with slightly longer paddles may be able to interbreed (in fact are pretty much sure to be able to interbreed) with those with shorter. There has been no speciation yet. The long paddle form may dominate or be 100% in the population but still there has been no barrier to interbreeding (if the others were still around). The same can be said for many of the changes needed. (blow hole position, backbone flexibility, rib arrangement, ear structure and so on).You are asking questions which don't seem to be very sensible with any understanding of the processes involved. That is one reason why there is not firm number. It is also, for reasons given, not an number that you can be sure of pining down with any certainty.What we do know from taphonomy is that very, very few individuals fossilize (none if they live in a habitate that is really hard on bones -- like rain forests). We also know that some land forms have been eroded to sand and dust -- including any fossils in them. In other words there are a ton of good reasons for expecting fossilization to be rare.So far you haven't given any good reasons (and no numbers) as to why it should be otherwise. I don't get this? I need more detail of what you are getting at.The comment about man's effect is irrelevant I think. The major impact on whales is only over the last century. I don't see how it ties in?

I'll do some work on backing it up when you have caught up with backing up your 90% for whales. My opinion there is based on the bit of reading in taphonomy that I have done (not a lot). Also others have pointed out to you that we have examples in bison and the passenger pigeon where millions and even billions of individuals left very few (1,000's for bison toward zero for passenger pigeons).I did read, quickly, your reference but can't find it right now. Could you both re suppy it and show how you got from specific items in it to 90% please. I am pretty darn sure that you number is a guess with no back up of any kind but I'm waiting to see otherwise.

It appears that this is telling us something useful. I'd interpret it as saying that we have found all the species that we are going to find not that we have found all the species that every were. Which is their interpretation too.So how does this help us arrive at the number of species that were there? It seems it doesn't help with that.

I'm prepared to change views when shown something that requires that.I think you are saying that there are a lot of missing whale fossils -- if whale evolution occured as hypothosized --- and that there should be many more of those fossils there.I think that there are a lot of gaps with fossils missing and I think that it is not surprising that they have not (and maybe won't be ) been found.If you can convince me that they should be there then I would have to wonder why they are missing. One possibility is that the evolution of whales did not take place as hypothosized. I would then be interested in how you do think that modern whales arose.

The above is all I see as input information. You then move this to: Why? Unless you think the transition took place multiple times we would expect the founder population to be much smaller than the diverged populations some 10's of millions of year later. How did you get from "relatively common" to "an abundance". We are supposed to be looking at numbers and you haven't found any numeric values yet. Now it has gone from an abundance to "massive". How did you get
there?Note that you are jumping around between species and families. That is careless too. It is much easier to represent a family than each species in it.You're not being intellectually honest here. Even if that were true, and there are obvious reasons for thinking it is not, what percentage of fish are fossilized? The article itself comments on reasons for different levels of fossilization.What this article is telling us is that the diversity of different groups appears to be reasonably well representated. That our older understanding of the nature of the evolutionary pathways was pretty good and that what we have now is enough to suggest there will not be any surprises in the future.As far as whales go you don't have enough information of any kind to draw conclusions yet.In fact you have darned little information at all.

As noted several times but you have ignored there may well be NO speciaion "events" involved. Zero, zip, nada and none you have not discussed that further and don't seem to have read the discussions on that issue. In the few snapshots we have there is no suggestion that I see that there had to be any clearly deliminated "events". We have never defined event carefully. I am useing the word the way you have previously.Many of the early changes needed to get to fully or nearly fully aquatic may have happened in a small, localized population (and for changes to fix in a population we know that there must be significant selective pressure and/or smaller populations).Now to get this back on topic (fossilization). If there has been a smallish (1,000's of individuals), localized (one area and niche in the world) population that has undergone evolutionary change with no sudden (less than 100's of generations) speciation "events" then we will not have as many potential individuals to fossilize as you seem to think.In addition, I just realize, you have been mixing two very different numbers (or we all have): one is the number of fossils that should have been formed the other the number that we should have found. They are very, very far from the same thing.The number of fossils formed and intact depends on things like the number of individuals that every exisited, the type of environment they lived in, the extent of their geographic spread and what has happened geologically since they would have been laid down.The number found depends on how much effort has been expended and the geologic changes that have happened (to expose or not expose the sediments for example).You have not yet developed anything like a reasonable numberical estimate of what we should expect to find. This does not follow. What stops several of the changes needed to make the transition happening in one small population, in one area together.That is, as has already been noted to you, you can change the location of the nostril, have a more flexibile backbone, make feet more paddle like, reduce the external ear all within individuals in one population at about the same time. This could all happen with one or a few species extant at anyone time without specific speciation events occuring just a gradual change in a population over time. I don't see how this follows.

Message 14Is the reply since it is off topic in this thread.Please do not ignore it I have given you a warning about using QM mumbo-jumbo there which is both off topic and nonsense.