Land Mammal to Whale transition: fossils Part II

As I mentioned in the original thread I believe this part of the question is a non-starter. Perhaps a professional or a more knowledgable (than me) amateur can explain why the reasoning below is wrong.To answer the question "How many samples along the whale evolutionary path should we expect to find?" we need to be able to guestimate at least two numbers:

• How many identifiable species would we expect in whale evolutionary history?
• How many of these species can we expect to find in the fossil record?

Number 1: How many identifiable species would we expect in whale evolutionary history?
As far as I am aware none of the science disciplines allow us to predict this number. Essentially all the ToE can do in this situation is say that between an ancestor species and a descendant species there will be intermediate species showing features somewhere between the two in a kind of sliding scale.Number 2: How many of these species can we expect to find in the fossil record?
Again I would say this number cannot be predicted. There are just too many factors involved, not the least of which is dumb luck. Others include (off the top of my head) environment, subsequent erosion or other means of destruction such as subduction, population size - I'm sure there's lots more. Ultimately we have to calculate how many of the intermediate species would have at least one member fossilise and then how many of these fossils will survive to the present and be found by us. We can't answer either of these.I can believe that you might be able to produce a formula that provides the answer to the question "How many samples along the whale evolutionary path should we expect to find?". It would unfortunately be like the Drake Equation for working out how many civilisations exist in the Galaxy. We don't know the values to use for so many of the terms that by using different values you can get pretty much any answer from 0 to billions.

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It all sounds like good stuff to me.I think the fool's errand part may be if you have any vague hope of convincing folks like randman.

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

quote:

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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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In Message 159 I quoted a post by Ned in another thread which referenced this link.This claims that we have fossils for roughly 0.1% of extinct animal species. The basis for this figure is as follows: Do we all accept this as a working starting point or has someone got a better supported etimate?Edit: Add this comment! Previous edit was to add the final line ("Do we all...") and to change the subtitle from "Rarity of..." to "Likelihood of...".This message has been edited by MangyTiger, 08-14-2005 10:59 PMThis message has been edited by MangyTiger, 08-14-2005 11:01 PM

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I don't understand this sentence. Could you define the term "form" you have introduced (just to make sure we are all talking about the same thing) please?When you say 'the more narrow definition of species' what do you mean? More narrow than what?

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I just spotted this. What are you talking about - where did the 'great many undiscovered living species' appear from? The great many undiscovered species being talked about in the link I posted are fossil species.

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You're missing something big time.There are three key numbers to understand.The first is the guestimate that there are 1,000,000 animal species alive today. This is based on simple observation plus some guesswork regarding how many unknown species there are in places like the Amazon rainforest (factors such as rate of new finds are used to calculate this). There is no evolutionary assumption in this.The second is that there are 100,000 known fossil species. This is based on counting the fossils in the museums, not evolutionary theory!The third is the biggest guestimate of all, that there 100,000,000 species have existed and gone extinct. This seems to be a bit of a stick your finger in the air number based on the number of species currently alive and how long ago animal life appeared. Again, this isn't based on evolutionary theory.

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I've got to go to bed now but I'll answer you later today I hope.I think I know where they got the number from (and the numbers to derive are almost all in the link if you think a bit laterally) but I'll try and check it up a bit more.

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I haven't had enough time to get to this until now and the thread has moved on past this, but since I said I'd reply...There are around 1,000,000 living species of animal. The 100 multiplier used to get the number of extinct species is (I think) just got from the average life span of a species - around 4 to 5 million years - seen in the fossil record and the time since animals appeared.

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