The Scientific Method of Evolution - Tangential Issues

[sandy_mcd]

we also know that it [evolution] does NOT occur at all levels! ... If you remember nothing else from this entire debate, remember to ask yourself this - if the appearance of complex life in the Cambrian explosion cannot be explained by evolution then why should we assume that later developments can be? ... We need empirical evidence.

It would be nice to have absolute proof of how evolution at that time occurred (presupposing that it did) or at least current knowledge of a way (or ways) it could have happened. But I get stuck at the, scientists can't figure out how it happened and it certainly seems unintuitive that it could happen, therefore it didn't happen, step. It is not "we know that it does NOT occur at all levels!" but "we do NOT know that it does occur at all levels!". In general, proving that something couldn't happen is so much harder and takes so much more knowledge than proving that something has or could happen. I am not convinced that anyone has accomplished this regarding evolution.

[Wall-dog]

Sandy,

I don't propose that anyone disproved evolution at the phyla level. But I do think that the fossil record points very clearly away from it. The gap from single cell organism to even BeGood's diagram of a creature (with cutout) is just too great. Archeologists have been searching for fossils literally for hundreds of years and the more they find the shorter the timeframe gets. When you look at the fossil record on the phyla level, evolution just doesn't fit. And once you throw it out on one level it no longer makes sense to pre-suppose it at other levels.

It's not just a matter of saying "we don't know how evolution occurred at that level." It's more than that. It's more like "given the evidence, we don't know how evolution could have occurred at that level."

If you believe in evolution at the phyla level, that is your choice. But you must recognize that you are believing in it not just in the absense of empirical evidence, but in the face of tremendous empirical evidence against it.

Now BeGood I'm sure is going to post something to try and breathe life back into his Cambrian explosion argument but he can't do the one thing he needs to do to make evolution work. He can't extend it. He can't give evolution the wiggle-room it needs. And proposing that a protein folded while a single-cell organism split and BAM! there's a crocodile just isn't going to cut it. Can I absolutely disprove that a single cell organism gave birth to a complex, phyla-level creature? No. But even if that's what happened I'd have to call it something other than evolution. Even BeGood's best 'evolutionary' guess smacks of God.

[BGoodForGoodSake]

The Cambrian pictures are a parlor game. BeGood has already agreed with Dr. Wells that animals within a given phyla have more in common with each other than they do with animals in other phyla.

Again you don't understand the meaning of Phylum. The reason that all chordata belong in the same phylum is because they posess a notochord, and later spinal chord. The image I provided is a representative of this group.

Showing a picture of two vastly different creatures to show that they look very little like later creatures does not explain how those creatures came about. You go from single-cell organisms and sponges to all phyla in a span of no more than 10 million years.

No worms, sponges and jellyfish existed pre-cambrian.

Some Chinese scientists (where many of the fossils are coming from) are saying it was only 5 million years.

Have you looked at the evidence?

Look at what BeGood has already posted. He shows an incredibly complicated creature complete with intestine, esophagus, epidermal, cuticle, and a cerebral ganglia (primitive brain).

All present in worms.

He could also have put up pictures of creatures with eyes and skeletons but for obvious reasons he wants to use the simplist-looking organisms he can find.

Now your being misleading There are no organisms which posses skeletons in this period.

Remember that these creatures shows up in the blink of an eye with no ancestors.

You know this for sure?

Evolution has no explanation for them. All BeGood can do is say 'hey - they don't look like crocododiles so they must have evolved!' In truth, the phyla the crocodile is in has far more in common with the crocodile than it has in common with any of the other phyla from the period.

I think it's clear that the primitave chordata has far more in common with a worm dthan it does with a crocodile.

So my 'BAM there's a crocodile!' analogy stands exactly as before. It's exagerated for emphasis but the premise is absolutely true. So we go from single cell organisms to advanced and incredibly complex life in 5 to 10 million years. You want more pictures? What I'd like BeGood to post is how fast evolution has to get before he's willing to give it a speeding ticket.

See your sticking to that mental picture without even examining the evidence.

Here is the thing. For the theory of evolution to hold the model has to work using unguided principals. Once you throw that out suddenly all of the other breaks in the fossil record are up for grabs too. And every fossil is an island. There are no chains - only islands. Evolution looses it's empirical backbone on the Cambrian explosion. While we know it occurs at some level we can no longer assume that it occurs any further than we can actually account for because we also know that it does NOT occur at all levels!

Again you misunderstand the classification scheme, the levels appear because through time diversification occurs at the only level possible, populations.
Here's an analogy, two twins begin in the same spot at age twelve. They decide to walk in opposite directions one east and one west, after about one week their set of experiences has diverged, we will call this species level diversification. After a month their shared experiences are even greater, lets call this genus level difersification. After 30 years they have a great deal of disparate experiences, this we'll classify as order level diversification. After 60 years they have completely different experiences, this is phylum level.

Now to fill it in lets say that at each point in time in the above example each twin split in two. The two branches of twins, one heading east and one heading west represent two phyla.

To pull out a succinct part of that long Wells quote:

According to Darwin's theory of evolution, all animals are descended from a common ancestor in the distant past. Supposedly, a single primitive species gradually diverged into two species, then those diverged over millions of generations to the point where we now see the major differences in body plans among worms, clams, crabs, starfish and vertebrates. Yet when we look at the fossil record we see that most of these major differences were present at the earliest appearance of animal life. Darwin himself knew this, and in The Origin of Species he called it a “serious” problem for his theory.

But what are the major diferences we are talking about?

Here are the phyla present in the cambrian.
Porifera - sponges
Annelida - segmented worms
Cnidara - nematocysts (stinging harpoon like cells)
Mollusca - mantle

Echinodermata
Arthopoda - exoskeleton
Nematoda - The first Nematode fossil is found in the Cenzoic
PlatyHelminths - Absent in the fossil record
Bryozoa

The first list has representitives in the Vendian Period
The second list contains some phylum which have not been found before the ordavicion.

In all there are 30 modern phylums some 9 of which appear in the Cambrian for sure and several more which probably originate in the cambrian. And along with this there are several perhaps 5 or more extinct phylums originating in the Cambrian.

The geologically abrupt and simultaneous appearance of most of the major groups of animals is now known as the “Cambrian explosion,” after the name of the geological period in which they first appear. Darwin thought that the Cambrian explosion might simply be an illusion caused by flaws in the fossil record, but a hundred and forty years of additional fossil collecting have dispelled this notion. Paleontologists James Valentine and Douglas Erwin wrote in 1987 that the Cambrian explosion “is real; it is too big to be masked by flaws in the fossil record.” And in 1991, Valentine and his colleagues wrote that the Cambrian explosion “was even more abrupt and extensive than previously envisioned.” (In Raff & Raff, eds., Development as an Evolutionary Process, Liss, 1987, pp. 84-85; and Evolutionary Biology 25, 1991, pp. 279-281)

I wonder how out of date this is?

What BeGood either fails to understand or (more probably) just isn't willing to admit is that this statement, which he made, proves the point:

But for the record I did not want to imply that all the forms were similar, only that the words first appearance of a particular phylum produce a far different mental picture than the actual evidence.

You misunderstand me, I am not saying all cambrian forms are similar, but you are overstating the differences greatly. All I am asking is for you to look at the evidence yourself.
Well lets take a look at the evidence and look at what the latest ideas are.

Annelida are a group of animals, the segmented worms, which appeared in the vendian precambrian.
It is beleived that the first arthopods, and brachiopods came from this lineage.

Arthopods - later to be insects, spiders, crabs etc..



And there are precambrian arthopods.
This one appears very similar to trilobites in the cambrian.


Here is a transition form between a segmented worm and an arthopod.
Which one is it?


Now for Brachiopods.


From here Moluscs are thought to have come from brachiopods.
We could spend all day on this so I will reserve more if there are further inquiries.

The 'mental picture' isn't relevant. What is relevant is that evolution cannot account for those organisms. Folding proteins and the notion that a single cell found a new piece of ocean and said "Hey! This isn't populated yet. BAM I'm a really advanced organism now!" well - that just doesn't work. I mean when you really think about it, it just doesn't work.

Primative sponges are basically a colony of single cells working together. No-one said Bam! That is again your mental image of it.

Who cares what those incredibly complex creatures looked like? They sure didn't look like anything that came before them.

New discoveries have confirmed the link between arthopods and annelids are you sure we won't find more?

And since evolution DEFINITELY cannot explain the phylum, why should we believe without empirical proof that it occurred at other levels?

A manipulation of ideas. There really are no levels. Its an abstract concept.

In any case do these organisms bear any resembelance to modern forms?

They don't do they.
Lets take away the idea of evolution all together.

All you have left is a collection of wormy bug like things. On what basis can you claim that there is an explosion? Only in the context of evolution and classification is there an explosion of forms.

[BGoodForGoodSake]

And proposing that a protein folded while a single-cell organism split and BAM! there's a crocodile just isn't going to cut it. Can I absolutely disprove that a single cell organism gave birth to a complex, phyla-level creature? No. But even if that's what happened I'd have to call it something other than evolution. Even BeGood's best 'evolutionary' guess smacks of God.

Please stop saying protein folding and Bam.
It's very disheartening and depresses me.


It only highlights my failure in educating you on biology.

Organisms consist of cells. Their organization is due to proteins.
Cells consist of proteins, whose sequence is a reault of a gene.
A protein folds according to the laws of nature.

When there is a change in genetic sequence, you can have a slightly differently shaped protein.
The shape of the protein determines its function.

New shapes can lead to new functions
New functions can lead to new behaviours.
New functions can lead to new forms.
New forms lead to new traits.

Get it?

[AttentionKMartShoppers]

Please stop saying protein folding and Bam.
It's very disheartening and depresses me.
Crying or Very sad

He must watch Emeril

[BGoodForGoodSake]

Please stop saying protein folding and Bam.
It's very disheartening and depresses me.
Crying or Very sad

He must watch Emeril

[Wall-dog]

BeGood,

I don't need a biology class. I think I understand biology just fine. In fact, I'm saying that folding proteins can NOT create incredibly complex life from single-cell organisms in a BAM there's a crocodile fashion. You are the one who is missing the point. Your entire last post dances around the whole issue. Let's get right to the point. How fast can evolution go? Explain to me how we get from single-cell organisms and sponges to all phylum in a span of only 10 million years (5 million according to many Chinese scientists). I think what you said earlier is that proteins can fold causing massive mutation overnight. It went something like this:

Wall-dog wrote:
Also, it is important to note that sufficient time must exist for evolutionary change to create a new species or to create separate species. How much time is 'sufficient' may be up for argumentation, but it's not something that will happen overnight.

Your response:

Actually it can happen overnight.

You made the statement and then you discussed folding proteins and massive mutations. Overnight. That's like BAM there's a crocodile. Or with Emeril picture a plate with nothing on it. He pulls out his Essence and BAM there's a stuffed Turkey. BAM here's desert.

We have nothing but single cell organisms and sponges today and BAM tomorrow we have complex life. How fast can evolution go before you start to get nervous.

How fast can it go?

Wall-dog wrote:
Another important point is the evolutionary notion that life was created in a non-intelligent manner - that amino acids assembled themselves into proteins and that proteins assembled themselves into cells.

Your response:

No, evolution does not cover the origin of life. The theory only covers the diversification of life.

Let us graph this out. Take a piece of paper and draw a line at the top. At the very far right, write the word 'species.' Color that part of the graph dark green because we KNOW evolution occurs to create change within the species level.

Now go all the way to the left and write the word 'No life.' This is how the Earth started. There was no life. Color no green here because there was no evolution.

Go about 1/3 of the way across the paper and write 'Single-Cell Organisms'. No green here either. You gave that up when you said evolution doesn't explain it.

Go almost all the way to right again - maybe an inch before 'species' and write 'Phylum'. No green here either until you explain the Cambrian explosion going from single-cell organisms to incredibly complex life overnight.

At this point you will have framed out the evolutionary debate and one thing will be remarkably clear. The best case you can make is that evolution became a part of the process at the very end.

Because evolution didn't occur at the phylum level, why should we assume that it occurred anywhere else? Here is what Dr. Wells had to say on that:

So as we go up these different levels in the taxonomic hierarchy - species, genus, family, order, class - common ancestry is certainly true at the species level, but is it true at the higher levels? It becomes an increasingly uncertain inference the higher we go in the taxonomic hierarchy. When you get to the level of the phyla, the major animal groups, it's a very, very shaky hypothesis. In fact, I would say it's disconfirmed. The evidence just doesn't support it.

I'll ask it again.. How fast can evolution go?

[BGoodForGoodSake]

BeGood,

I don't need a biology class. I think I understand biology just fine. In fact, I'm saying that folding proteins can NOT create incredibly complex life from single-cell organisms in a BAM there's a crocodile fashion. You are the one who is missing the point. Your entire last post dances around the whole issue. Let's get right to the point. How fast can evolution go? Explain to me how we get from single-cell organisms and sponges to all phylum in a span of only 10 million years (5 million according to many Chinese scientists). I think what you said earlier is that proteins can fold causing massive mutation overnight. It went something like this:

Wall-dog wrote:
Also, it is important to note that sufficient time must exist for evolutionary change to create a new species or to create separate species. How much time is 'sufficient' may be up for argumentation, but it's not something that will happen overnight.

Your response:

Actually it can happen overnight.

Not from massive mutations but from a doubling of chromosomes. You take two disparate ideas and put them together?

It's called polyploidy.
http://www.biolo.aichi-edu.ac.jp/NIOC20 ... /37-40.pdf

You made the statement and then you discussed folding proteins and massive mutations. Overnight. That's like BAM there's a crocodile. Or with Emeril picture a plate with nothing on it. He pulls out his Essence and BAM there's a stuffed Turkey. BAM here's desert.

If you are uncertain of something you can always ask questions before making any jumps to a conclusion.

We have nothing but single cell organisms and sponges today and BAM tomorrow we have complex life. How fast can evolution go before you start to get nervous.

The first sponge fossils appear 110 million years before the Cambrian started.

How fast can it go?

What are we talking about here, I want to make sure you understand what forms we are talking about there. there are no crocodiles in the fossil record until 291 million years after the Cambrian began.

Wall-dog wrote:
Another important point is the evolutionary notion that life was created in a non-intelligent manner - that amino acids assembled themselves into proteins and that proteins assembled themselves into cells.

Your response:

No, evolution does not cover the origin of life. The theory only covers the diversification of life.

Let us graph this out. Take a piece of paper and draw a line at the top. At the very far right, write the word 'species.' Color that part of the graph dark green because we KNOW evolution occurs to create change within the species level.

Now go all the way to the left and write the word 'No life.' This is how the Earth started. There was no life. Color no green here because there was no evolution.

Go about 1/3 of the way across the paper and write 'Single-Cell Organisms'. No green here either. You gave that up when you said evolution doesn't explain it.

Go almost all the way to right again - maybe an inch before 'species' and write 'Phylum'.

See this is where you're understanding breaks down. Relatively minor differences in body design lead to radical differences down the line. Unless you are talking within the context of evolution a primitave chordate is only a worm with its nerve along the ventral side rather than ventral side of it body.

Think of it this way the current classification system has phyla at the top and it breaks down into order class family genus etc...

The first differentiation between organisms is the same as the differentiation going on today. Only over time the differentiation occurred so long ago that the descendants of each are grouped in larger and larger groupings.

See below.
Think of it like a tree. First you have a trunk which splits into 4.
Sponges, Jellyfish, roundworms and segmented worms. Probably in that order.
Then off of the segmented worms you have 5 or 6 more branches, brachiopods, arthopods, some extinct lines, and chordates.

Off of the brachiopods you have molluscs.
Off of the chordates you have even more branches echinoderms??,urochordates,fish,amphibians,reptiles, etc... Any thing which branches off of these first few branches are what we classify as phylum. Although at the time of branching there is no full fledged change from one type into another, at the time a modification to body design, but looking back and taking modern forms into consideration a major change.

But look at the first chordate, does it more resemble a bird or a worm?
Take it out of evolutionary context, what do you have here?

No green here either until you explain the Cambrian explosion going from single-cell organisms to incredibly complex life overnight.

Again it's not going from single cells to multicellular complexity, look at the fossils.

At this point you will have framed out the evolutionary debate and one thing will be remarkably clear. The best case you can make is that evolution became a part of the process at the very end.

Again you fail to understand that basic body plans is how the various phylums are arranged? Why because the forms which followed carried with them the body plans of the original forms. For instance a Bird has a vertebra along the back. As does an aligator, that is why they are in the same phylum. The original chordate which we find in the cambrian layer also has a nerve which runs along the dorsal side.

Because evolution didn't occur at the phylum level, why should we assume that it occurred anywhere else? Here is what Dr. Wells had to say on that:

???Again what are you talking about?

So as we go up these different levels in the taxonomic hierarchy - species, genus, family, order, class - common ancestry is certainly true at the species level, but is it true at the higher levels? It becomes an increasingly uncertain inference the higher we go in the taxonomic hierarchy. When you get to the level of the phyla, the major animal groups, it's a very, very shaky hypothesis. In fact, I would say it's disconfirmed. The evidence just doesn't support it.

I'll ask it again.. How fast can evolution go?

Here look at this.
Cambrian Arthopod.

Modern Arthopod.


Cambrian Chordate

Modern Chordate


Cambrian Mollusc

Modern Mollusc


So what do you mean by fast, I just want to clarify before attempting to answer your question.

Again if you take these fossils by themselves outside of the context of evolution there are no phylum here. Only when you recognize certain features shared by groups of modern animals in a cambrian fossil do you recognize the beginnings of a phylum, without the subsequent divergence all you have is a collection of very primitive animals. Would you not agree?

Or are you going to ignore this point again?

[Wall-dog]

BeGood,

You know exactly what I mean by fast. I can hear you tapdancing around the issue from my living room.

You have single cell organisms and sponges. You get no more than 10 million years. Show me how you evolve into any of the first phylum representatives.

[BGoodForGoodSake]

BeGood,

You know exactly what I mean by fast. I can hear you tapdancing around the issue from my living room.

You have single cell organisms and sponges. You get no more than 10 million years. Show me how you evolve into any of the first phylum representatives.

Lets see how large this jump is, I will create a new thread on protista, cnideria and porifera.

[Wall-dog]

Why start a new thread? We've got enough threads. Why not discuss it right here?

[BGoodForGoodSake]

I see you ignored the point for the third time, In case you missed it.

If you take these fossils by themselves outside of the context of evolution there are no phylum here. Only when you recognize certain features shared by groups of modern animals in a cambrian fossil do you recognize the beginnings of a phylum, without the subsequent divergence all you have is a collection of very primitive animals. Would you not agree?

Changes which occur at a species level early on can lead to phylum wide differences, do you have a problem with this statemet?

You may choose to ignore this again.
Very well we'll begin with protista.

http://www.windows.ucar.edu/cgi-bin/tou ... tista.html

Protista are unicellular or colonial eukaryotic cells.

These organsism are not like bacteria, they are much larger up to a thousand times larger.

They are Eukaryotic just like all the cells in a tree or you or me.
=)

Since we are talking mostly about animals lets focus on the protozoa.
Here's a common paramecium.


Some protozoans reproduce sexually, even though they only consist of one cell.
http://darter.ocps.net/classroom/klenk/Protist.htm


One thing to note about single celled organisms. Bacteria and protista alike they behave differently in different environments.

Some protozoa exist in colonies.
Volvox
http://www.btinternet.com/~stephen.durr/volvox.html

If you read the article you'll notice that specialization of certain cells have occurred. Even though it is a colony of single celled organisms, there is some sort of communication between cells to cause some to become photosensitive and others to become gemetephytes, etc...

Another Colonial protist is the slime mold.
http://www.ucmp.berkeley.edu/protista/slimemolds.html
There is particularily one type which are of interest in this discussion.

Cellular slime molds
These creatures spend most of its time as independant unicellular creatures. However they have the ability to combine together and form a single multicellular form, this is of interest to us because we are interested in intercellular communication.


Another interesting group of animals are the Choanoflagellates http://www.bigelow.org/cytometry/Image_ ... HOANO.html
I will get into more detail on these critters when we talk about sponges[/img]

[Wall-dog]

I'm not ignoring you. I'll refute you after you tell me how fast evolution can go from single-cell organisms to all of the phylum-level creatures that came out in the Cambrian explosion. You've got 10 million years (and maybe only 5). I want you to explain how it could possibly have happened so quickly and how it could have occurred without any evidence of any kind of evolutionary intermediaries other than BAM there's a crocodile.

[BGoodForGoodSake]

We ended off with Choanoflagellates.

These are single celled organisms.

Some form colonies.



Sponges are the simplist form of multicellular life.
They don't consiset of tissues per say but have a variety of types of cells which all work together.

One of these specialized cells are called choanocytes.

The similarity of choanocytes to choanoflagellate leads one to beleive they are related and molecular comparisons support this. Sponges could have been a result of colonial choanoflagellates becomming more organized. However it is equally possible that choanoflagellates are a reduced form of sponges.

As you can see sponge anatomy is very simple.
http://www.biologycorner.com/worksheets ... atomy.html

The first Fossil sponges were found in rocks dated to 580 million years ago. 40 million years before the Cambrian in the lower Vendian period.


Next we will discuss roundworms, flatworms and segmented worms.

[Wall-dog]

Excellent. Thank you for at least attempting to explain the timeline. I'll look forward to the rest of your explanation.