Cambrian Explosion

[Baggins]

The scientists were amazed at the diversity and didn't feel at all that it was sparse but in fact very abundant.

Only in as much as they didn't expect to see grass at all, and it pushed back the evolution of grass by a few million years.

5 species is not amazing diversity

 

[Mallon]

Very true, but the therapsids developed this movement in the jaw after the dino extinction...correct? So it is not relative to my point.

Incorrect. The mammalian jaw hinge evolved before dinosaurs were on the scene.

 

[Edx]

Jet, I am sorry. This new time change is just not working with me. (daylight savings time).

But, your profile says you are in America? Do they have daylight savings too?

 

[Oncedeceived]

Only in as much as they didn't expect to see grass at all, and it pushed back the evolution of grass by a few million years.

5 species is not amazing diversity

A few million years? It is more like ten million years.

The scientists felt that it was amazing:

"This is really pretty exciting," says Elizabeth A. Kellogg, an evolutionary biologist at the University of Missouri–St. Louis. If the research holds up, "it would completely revise what we've thought about the origin of grasses," she notes. "This isn't that much older than the oldest previous grass fossils, but to find such diversity at that time is surprising."

 

[Baggins]

A few million years? It is more like ten million years.

The scientists felt that it was amazing:

"This is really pretty exciting," says Elizabeth A. Kellogg, an evolutionary biologist at the University of Missouri–St. Louis. If the research holds up, "it would completely revise what we've thought about the origin of grasses," she notes. "This isn't that much older than the oldest previous grass fossils, but to find such diversity at that time is surprising."

Sounds a bit hyperbolic, what was she expecting 1 specie?

But if I pushed back the origin of grasses another 10 million years into the Cretacious I'd be pretty pleased with myself as well.

Not forgetting that the Cretaceous lasted for 81 million years.

Still does nothing to support your notion of pre-Cretaceous grasses that left no record mind

 

[Oncedeceived]

Sounds a bit hyperbolic, what was she expecting 1 specie?

But if I pushed back the origin of grasses another 10 million years into the Cretacious I'd be pretty pleased with myself as well.

Not forgetting that the Cretaceous lasted for 81 million years.

Still does nothing to support your notion of pre-Cretaceous grasses that left no record mind

What it supports is my premise that grasses were in existance for at least 10 million years without leaving a trace. That is a long time for absence of a fossil record when we know they existed.

 

[Gracchus]

Can't seem to insert the image, but it is here:

http://www.ucmp.berkeley.edu/phyla/metazoafr.html

This would indicate that all animal phyla did not appear in the Cambrian.

And if one adds the plant phyla which appear after the Cambrian, one gets the following chart.

Period # total phyla which appear in period
Recent 13
Eocene 2
Cretaceous 2
Jurassic 1
Triassic 3
Carboniferous 5
Devonian 4
Silurian 1
Ordovician 1
Cambrian 9
Vendian 4

(same note as above concerning phyla in the Vendian)

This yields Cambrian Explosion 13, Post-Cambrian 32!

http://home.entouch.net/dmd/cambevol.htm

IIRC, there were a couple phyla that appeared after the Cambrian and a number of phyla that went extinct. Plus, even if the phyla were present, most of the modern species weren't.

Twenty animal phyla and thirty-two phyla appeared after the Cambrian. That is more than a couple.

 

[Jet Black]

The Cambrian Explosion is just a taphonomic artefact anyway, since the conditions prior to the cambrian were not good for preserving fossils, whereas during the cambrian, there are a number of regions where the conditions were good.

 

[Jet Black]

Very true, but the therapsids developed this movement in the jaw after the dino extinction...correct? So it is not relative to my point.

no, therapsids such as Procynosuchus, Thrinaxodon and Probainognathus were developing this movement in the late permian and early triassic. That is before even the (dominance anyway) of the dinosaurs. By time we get to Hadrocodium in the early Jurassic, the mammalian condition of the jaw is very advanced.

I was making two separate points but I feel both are relative to the discussion.

I can see now. my apologies for jumbling them up.

Perhaps not scientifically, but if they were grass in form if not in genetic similarity, it would still be "grass". Remember I am not claiming that the Bible is a scientific journal, but only that it should not really conflict with known Scientific data. So it could remain grass...or grass like in our understanding but not be scientifically genetically linked to grass today. There are many forms that are extinct that have no known genetic links to organisms today.

well that would kind of negate the point of suggesting that what we know as grass existed in the precambrian.

But grass is grass according to form if nothing else. It would not be necessary for it to be scientifically named by cladistic relationship to be "grass" in form only.

but then what exactly do we mean then by grass? I wouldn't call a dolphin a fish because it bears some superficial resemblance to fish.

 

[Baggins]

What it supports is my premise that grasses were in existance for at least 10 million years without leaving a trace. That is a long time for absence of a fossil record when we know they existed.

I imagine that there are plenty of traces but they just haven't been found or recognised yet. One of the problems is that grass itself doesn't fossilise well, the other is the inherent difficulty of matching grass pollen and seeds to plants as they aren't very differentiated. But now a fossil has been found we can probably expect to have some progress in this area and I have little doubt that more fossils will be found, once a discovery like this is made it usually stimulates more people too look and hence more fossils are found.

 

[caravelair]

i'd like to bring up a post that has kinda been passed over...

okay, so you believe that the evidence we have today doesn't falsify grasses existing 3 billion years earlier than we think. don't you agree though, that the evidence we have right now is the strongest evidence we could possibly have that they did not exist then? if not, what evidence do you feel would more strongly indicate that? and if this is the strongest evidence we can have, and it still doesn't falsify your claim, then it must be unfalsifiable, right? and if so, doesn't that render all your other predictions unfalsifiable too? because you could always play this exact same trick with any other species, or basically anything relating to the past. any time something contradicts your predictions, you can just claim unfalsifiability.

this is my main point at this stage of the discussion. curious to know what you think about this, oncedeceived.

 

[Oncedeceived]

I imagine that there are plenty of traces but they just haven't been found or recognised yet. One of the problems is that grass itself doesn't fossilise well, the other is the inherent difficulty of matching grass pollen and seeds to plants as they aren't very differentiated. But now a fossil has been found we can probably expect to have some progress in this area and I have little doubt that more fossils will be found, once a discovery like this is made it usually stimulates more people too look and hence more fossils are found.

Exactly, that is one of my points.

 

[Oncedeceived]

i'd like to bring up a post that has kinda been passed over...

Sorry about that.

this is my main point at this stage of the discussion. curious to know what you think about this, oncedeceived.

Well first of all, I wouldn't call it a claim that I am presenting. That is more established than what I am saying here. I presented a possible scenerio, I think that is where you are getting off here. Just as for instance there is the RNA or DNA scenerio for the first life theories. See what I mean?

 

[Jet Black]

Exactly, that is one of my points.

where does this fit in with the cambrian explosion though?

 

[caravelair]

Well first of all, I wouldn't call it a claim that I am presenting. That is more established than what I am saying here. I presented a possible scenerio, I think that is where you are getting off here. Just as for instance there is the RNA or DNA scenerio for the first life theories. See what I mean?

sort of, but i still would like you to answer the 4 questions i asked in that paragraph, so that i can better understand where you are coming from:

don't you agree though, that the evidence we have right now is the strongest evidence we could possibly have that they did not exist then? if not, what evidence do you feel would more strongly indicate that? and if this is the strongest evidence we can have, and it still doesn't falsify your claim, then it must be unfalsifiable, right? and if so, doesn't that render all your other predictions unfalsifiable too?

 

[Oncedeceived]

where does this fit in with the cambrian explosion though?

Sorry? I don't know what you are asking.

 

[Jet Black]

Sorry? I don't know what you are asking.

well you were talking about the grasses in the precambrian a while back, and I wonder if this is still related or not.

 

[Oncedeceived]

sort of, but i still would like you to answer the 4 questions i asked in that paragraph, so that i can better understand where you are coming from:

don't you agree though, that the evidence we have right now is the strongest evidence we could possibly have that they did not exist then? if not, what evidence do you feel would more strongly indicate that? and if this is the strongest evidence we can have, and it still doesn't falsify your claim, then it must be unfalsifiable, right? and if so, doesn't that render all your other predictions unfalsifiable too?

1. Considering the fact that many organisms are being found earlier and earlier presents support that the evidence is not always as strong as it seems. Ants for instance, they have been found 40 million years sooner than previously thought. Bees too as I have pointed out have been found much much earlier than thought. With fossils it is hard to say just what evidence is conclusive. Any evidence that we hold at present may seem strong until some other evidence is found. So to say that the strongest evidence we can have is the strongest evidence there is becomes somewhat distorted.

2, 3, and 4. I have said that it is probably unfalsifible. Just as it is unfalsifible that there were no grasses present in the pre-cambrian, due to the fact that tomorrow someone could find evidence for them.

 

[Oncedeceived]

well you were talking about the grasses in the precambrian a while back, and I wonder if this is still related or not.

If grasses...plants were found in the pre-cambrian it does nothing to change the event of the Cambrian in my view.

 

[Jet Black]

If grasses...plants were found in the pre-cambrian it does nothing to change the event of the Cambrian in my view.

What event of the Cambrian? more than anything else the Cambrian is a taphonomic artefact. It is the first time you see these things, because it is the first time that you get good conditions for fossilization.

and I think we are getting a little bit lost on where the grasses fit in. I recall you saying that they some precambrian plants might be called grass because they look like that, but then one wouldn't call a dolphin a fish because it looks superficially like a fish.