Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 56 (9054 total)
69 online now:
jar, PaulK, Tangle (3 members, 66 visitors)
Newest Member: EWolf
Post Volume: Total: 888,214 Year: 5,860/14,102 Month: 8/438 Week: 52/83 Day: 2/6 Hour: 0/1


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Exposing the evolution theory. Part 1
caffeine
Member (Idle past 87 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


(5)
Message 32 of 41 (844430)
11-29-2018 2:04 PM
Reply to: Message 25 by Porkncheese
11-29-2018 12:05 PM


Re: Avoidance of the issue.
So far only defensive tactics and false accusations to avoid explaining the evidence of the missing fossils.

On the contrary, you just ignored the explanations.

The oldest fossils are not from the Cambrian. They're much, much older. How much older is a matter of great dispute, since of course the earliest fossils are microbes. Distinguishing a fossil microbe from a microscopic hole in a rock is not simple. The other approach is to look for chemical byproducts of life in the rocks; but again distinguishing these from something that could be produced by some chemical process that does not involve life is not simple.

The oldest claimed fossils that would be visible with the naked eye are a little over 2,000 million years old, found in Gabon. That's about four times as old as the Cambrian explosion. What they are is not entirely clear - photos below.

It has been argued that these are also inorganic in origin. The picture above comes from an open access article making the case for them being organisms.

The fossil record long before the Cambrian is full of acritarchs - which is essentially a word made up for little fossilised microscopic balls that are clearly of organic origin. What they are is in no sense clear, and they probably aren't all the same thing. They're much less common during ice ages, and they increase dramatically around the time of the Cambrian explosion.

Now, I'm sure this is all not satisfactory to you with your curious standards of evidence, but the important question here is to ask what evidence you would expect to find of microorganisms that existed thousands of millions of years ago? I can't see any reason to expect better.

The oldest unequivocal multicellular eukaryote fossil I know of is Bangiomorpha pubescens from Canada. It's probably a red algae, meaning it's in the same phylum as the nori you wrap your sushi in. This is thought because it's extraordinary preservation means scientists can actually study its cell division - here he is under a microscope:

The time between this fossil and the Cambrian explosion is about the same as between the Cambrian explosion and now.

We of course have many pre-Cambrian fossils, some identifiable as belonging to living groups. Kimberella is clearly an animal:

but what sort of animal is not clear. It's not the oldest animal - that title currently goes to Dickinsonia, dating to about 40 million years before the Cambrian:

Of course, it's not obvious from looking at this that that's actually an animal. Scientists are mostly convinced that it is by the chemical analysis done of these fossils, which shows the presence of cholesteroids - only animals make cholesterol.

And this is a key point to bear in mind. We have many pre-Cambrian fossils. But when people say 'molluscs appeared in the Cambrian without precursors' it seems deeply confused to me. There comes a point at which fossils are clearly identifiable as molluscs. Before that time, there aren't fossils clearly identifiable as molluscs - but there are still fossils. The problem is how do you tell which one (if any) is a mollusc ancestor, and why would you expect to be able to? If there are fossils with all the key identifying features of molluscs back to the beginning of the earth then we would doubt the idea of common ancestry. Because we think molluscs share an ancestry with everything else we expect there would be a time at which you can no longer find things with all the key molluscan features.

Add to this the fact that fossils get fewer as you go back in time, and vaguer when you no longer have hard parts to identify. How do you determine what Dickinsonia was? Was it an ancestor of molluscs, of annelid worms, of arthropods? Who the smeg knows? But if the theory of evolution is correct, why would you expect this to be otherwise?

This is not to say the Cambrian explosion was not a real event - it may well have been. Explosions in diversity have happened many times - you mentioned another one. After the K-T boundary where the dinosaurs went extinct there is an explosion in diversity. Why? Because the dinosaurs (along with a bunch of other organisms) just went extinct - life diversified to fill the empty ecological niches.

But the statement that Primates suddenly appear here without precursors is odd. For starters, there aren't any primate fossils that old. There are plesiadapiformes - these are considered to be either ancestors of or close relatives to primates, so the idea primates don't have known evolutionary precursors is obviously a nonsense.

(There's a fantastic fossil of Plesiadapis in the Muséum national d'Histoire naturelle in Paris in which you can see the impression of the animal's bushy tail in the rock which should go here, but I can't find a picture anywhere online).

Once you go back before the extinction of the dinosaurs, things get more complicated. But not because there aren't fossils. There are - the problem is again in figuring out which, if any, are the ancestors of primates. But of course this is the case! As you point out, the idea is that all life has a common ancestor. Once you go back far enough you hit the point where fossils no longer have the distinctive features of primates; and then how do you tell if it's the ancestor of primates, or of rodents, or of both, or of neither. Scientists have had precisely that argument (at length) about these ankle bones:

I'm not seeing any problems you've posed for the 'naturalistic theory' as of yet.

Edited by caffeine, : No reason given.

Edited by caffeine, : No reason given.


This message is a reply to:
 Message 25 by Porkncheese, posted 11-29-2018 12:05 PM Porkncheese has not yet responded

caffeine
Member (Idle past 87 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


(3)
Message 40 of 41 (844473)
11-30-2018 4:34 PM
Reply to: Message 39 by Stile
11-30-2018 1:49 PM


Re: Looks fine to me
I think that picture's pretty good to show kids.

It's a bit out of date. This one below is a) more in line with modern hypotheses, b) more detailed and c) available as a jigsaw puzzle, so it wins on all fronts.


This message is a reply to:
 Message 39 by Stile, posted 11-30-2018 1:49 PM Stile has acknowledged this reply

Replies to this message:
 Message 41 by Tanypteryx, posted 11-30-2018 5:27 PM caffeine has acknowledged this reply

Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2021