The fossil record explained

[Turkana]

There creationist posters like Heisonear here who are constantly singing their mantra about "the fossil record doesn't testify for evolution." Unfortunately with a thorough misunderstanding and ignorance of what paleontology actually implies - the scientific discipline dealing with fossils.

So I have to explain paleontology.
I find it kind of peculiar having to explain something to people who apparently feel entitled to criticize stuff instead of getting knowledgable about it first.

There are two different things in paleontology:

1. reconstructing the pedigree-like lineages of ancestor to descendant species. This is about to reconstruct and assign the actual ancestral species that brought forth particular species.

2. providing evidence for evolution by showing there are transitional forms between ancestor and descendant.

They are quite different. While reconstructing pedigree-like lineages involves assigning past species as the *actual* ancestor, so dealing on the species-level, providing evidence for evolution mostly is on a higher taxonomical level and no particular, actual ancestor needs to be assigned. Let me explain:

The task here is to demonstrate the gradual transition in traits between taxa that are mostly (almost always) higher than the level species. For instance, cetaceans share common unique traits that make them "cetaceans". Also artiodactyls (=even-toed ungulates) share *unique* traits that make them "artiodactyls". But it happens that in cetaceans we spot many of the traits that are unique to artiodactyls as well. That already provides an indication about their ancestry, corroborated by the observation that of all extant animals, hippopotamus (an artiodactyl) resembles cetaceans most by DNA comparison.

And it's the gradual change in traits from *artiodactyls* to *cetaceans* we clearly observe in the fossil record. Paleontologists are not even particularly interested in Pakicetus (an ancient land artiodactyl that already exhibited some primitive cetacean traits) being the actual ancestor of extant cetaceans. We can't even know because the very next year we might find a fossil of a sister species of Pakicetus that qualifies even better as actual ancestor of cetaceans.

So, mostly the transition of traits is between higher taxa than species, mostly in families, orders or classes. So while we can't be 100% sure Pakicetus was the actual ancestor of cetaceans, we definitely know that cetaceans, taxonomically spoken an infraorder, evolved from artiodactyls, taxonomically spoken an order. Even more, cetaceans, cladistically spoken, belong to the artiodactyls. They are artiodactyls. Because cetaceans have some traits that are entirely unique to artiodactyls AND we have the fossils that clearly show the gradual transition from artiodactyls to cetaceans.

In a next post I shall spell out how paleontologist figured out that cetaceans are artiodactyls and how many fossils testify of cetaceans having evolved from artiodactyls. Because otherwise this post will become too long.

It always brings a smile to my face when paleontologists find some new transitional, hominid fossil and scratch behind their ears to figure out whether it should be classified as a "pithecus" ("ape-like") or "hominid ("human-like"). Often they fight like cats and dogs. Surely taxonomists must classify new fossil species but the great trouble they have doing so is *because* of the transitional character of such fossils and they actually thus should be happy about their own troubles because fossils that are very difficult to classify are the hallmark of evolution.

 

[Turkana]

So here's my second post in my attempt to explain paleontology. It will be about the stratification of the fossil record.

As we all know (I hope) we observe earth layers beneath our feet. You just start to dig or observe showcases like the Grand Canyon where nature neatly carved out a deep ravine with all layers exposed for observers to behold. There is a simple rule in geology: generally, the layer below is older than the one on top. That's sheer logic. There are some rather rare exceptions but these are well known and explained.

Now what exactly do we observe in all those layers?

• when you start to excavate the geological column on any random spot you invariably see a lot of geological layers and entire formations piled up on top of each other. On such a random spot you might see sandstone sitting on limestone with fish fossils, alternated with a thick layer of coal, then limestone again, followed by a layer of chalk etc. etc. That means that very same spot once was a desert, then a sea floor, then a forest, then a sea floor again, ending up in shallow coast line. And this is quite the general picture everywhere, irrespective where you start to dig and excavate.
  
  
• the fossil record of each formation is unique in the way that it contains fossils that are found in no other geological layers whatsoever. For instance, in the formation called Ediacaran, you find life forms that are entirely alien to what we see today and, conversely, you won't find any of the following groups of life forms there: fish, arthropods (insect and the like), amphibians, reptiles, dinosaurs, birds, mammals and land plants. As a matter of fact, during the Ediacaran there was no land life at all, apart from bacterial and algal mats. The life of the Ediacaran looked as if you were watching a SF B-movie.
  

In other words, there is no other interpretation possible for these observations: life forms changed over time. Whole new species, complete new classes, orders and even entire phyla of species emerge while they are completely lacking in the older formations. That is called evolution.

There is no other way to interpret this differently.

And, note that I did not make any assumptions about the factor time: I ONLY implied that geological formations differ greatly in biodiversity. I did not say anything about their actual age or even about which one to be older or younger. I do not need to assert anything about time to prove that the fossil record unambiguously and inescapably forces us to conclude that life changed over time during the natural history of the earth. There is no getting around that.

In other words, due to the stratification of the fossil record, the geological record on its own already suffices greatly as evidence for evolution.

At this point, let's go back to the cetaceans.
Cetaceans simply appear later in the fossil record than land artiodactyls. Because older geological layers were already swarming with artiodactyls well before any cetacean arrived on the scene. But, as I explained in my OP (I will come back with the details in my next post) cetaceans ARE artiodactyls. You may do the inference yourself.

Up to the details in cetaceans and artiodactyl fossils. Which will be my third post next.

 

[Turkana]

So what are the actual, observational actual details that make paleontologists decide that whales and other cetaceans like dolphins come from land and evolved from land artiodactyls?

But for that I would lke to take Dorudon rather than Indohyus and Ambulocetus as the video does.

Dorudon was a cetacean that lived in the Eocene. Beyond any doubt it was a marine animal, you can tell this from its streamlined body shape.

First of all, let's examine why paleontologist find that early cetaceans like Dorudon (or Ambulocetus for that matter) are mammals. You can tell from anatomy, DNA, physiology and behavior, like:

• they breath through lungs, not gills
• females produce milk to feed their newborns
• specifically they belong to the placental animals (and not to the marsupials or monotremes)
• they give live birth
• the inner ear anatomy (mammalian middle ears contain three tiny bones known as the ossicles: malleus, incus, and stapes and this threefold structure is unique in the animal kingdom, so paleontologist may only find a fossil part of the skull and they can tell it belongs to a mammal)
• they are warm-blooded
• they propel through the water by up/down instead like fish left/right movement of the spine (unlike, for instance, reptiles, these still move around the way fish do by a left/right undulation)
• and some hundreds of other traits that link them to mammals.

Note: the traits above are mostly unique to mammals but there are some individual exceptions, for instance, live birth is also observed in other non-mammal species like some sharks but it is the total picture of hundreds of traits that make the point (and of course especially telling concerning traits are certainly unique for mammals).

But the most telling trait that binds cetaceans to the mammals is their genetic make-up: of all animals living on earth, the one that resembles cetaceans genetically most by DNA comparison, is hippopotamus, an artiodactyl. Not all too surprisingly, hippopotamus is a semi-aquatic land animal.

And here are the details about the anatomical evidence for cetaceans being artiodactyls:

• the double pulley joints anatomy of the ankle, a trait unique for artiodactyls (mentioned in the video)
• a hooked knob pointing up towards the leg bones in the astralagus, unique for artiodactyls (also mentioned in the video).

To make the evidence complete, the next step is to prove that Dorudon (after all it's an extinct animal so we only have its fossils to establish this) should be classified as a cetacean:

• alignment of the upper incisors with the cheek teeth (typical for cetaceans)
• the nostril is not in the tip of the snout but has travelled halfway its head (the blowhole in whales)
• the ear region is surrounded by a bony wall (the thickened involucrum mentioned in the video)
• reduced pelvis and hind limb size (I come back to this!)
• particular structure of the tympanic bone
• the anatomy of the teeth...

… and a few other traits that are unique for cetaceans.

But the most telling evidence for cetaceans having evolved from land animals are the pesky hind limbs of Dorudon.

Dorudons and also another later, extinct cetacean, Basilosaur (mentioned in the video), have fully developed hind limbs, attached to a pelvis and, another specimen (both linked examples are of the species Dorudon atrox).

Those hind limbs were still fully developed according to basic amniote anatomy. Amniotes, meaning "membrane surrounding the fetus", are a clade of tetrapod ("four footed") vertebrates comprising the reptiles, birds, and mammals that lay their eggs on land or retain the fertilized egg within the mother, both of which are made possible by the membrane - the anamniotes like fish and amphibians don't have such a membrane and need to lay their eggs in water. Amniotes can lay their eggs on the dry land which enlarges their habitats greatly.

The typical amniote hind leg anatomy is:

• femur including patella
• fibula and tibia
• tarsals and metatarsals
• digits
• neatly attached to a pelvis.

But perky those hind limbs were indeed:

• first of all, they were extremely small for such rather large animal (Dorudon was ~ 5 meters tall and weighted some 2 tons). The size of Dorudon’s hind limbs was about a modern housecat’s ones. I don’t think an animal that long and heavy could have walked with such small hind limbs
• but, moreover, the pelvis was detached from its spinal cord. You just can’t walk with hind limbs detached from the spinal cord
• also much of the ankle bones and carpals were fused as well, again making walking impossible.

Now the next, profound question here is: what was a full-blown marine animal doing with fully developed, amniote type of hind limbs which were detached from the spinal cord and too small for such a large animal and whose ankle bones and carpals were fused, making walking entirely impossible. In other words, what was a fully marine animals, that used front flippers and a tail fluke for propelling, doing with hind limbs in the first place but also ones it couldn’t walk with?

Well, it's because those hind limbs are vestiges and point out to the terrestial origine of cetaceans.

It's immediately here important to tell that vestiges are not necessarily functionless. The vestigial pelvises in cetaceans still in some species attach to the male sexual organs. That indicates some function (a kind of anker of the penis). I don't believe it is but let's say it actually does. That still makes the cetacean hind legs and pelvises vestiges:

• it's still vestigial since the pelvis isn't doing "pelvis things" like providing a joint for leg bones, and anchor points for leg and back muscles
• the "function" it still may have for sexual reproduction is that it's attached to the penis via a ligament. It actually is useless in females (and I add that in all vertebrates the sexual organs are fixed to the pelvis, so this might as well count as evidence for evolution)
• the femur often in modern whales isn't attached to anything or the pelvis is even entirely lacking. So how are in these species the males performing?
• some dolphins have gotten rid of it entirely and have any pelvis or hind leg structure left at all and still manage to reproduce. Which is typical of vestigial structures, they are sometimes completely absent in some individuals, some humans don't have wisdom teeth, for example.

Now why did cetaceans end up in the oceans. We have a good explanation for that: cetaceans evolved in the aftermath of the demise of the non-avian dinosaurs. These were wiped out ~65 millions of years ago mostly due to an asteroide impact (that also caused numerous other groeps of animals to go extinct).

Among those extinct dinosaurs there were species living in the oceans in the same ecological niches cetaceans today dwell. So when those dinosaurs went extinct, they left niches open to be occupied.

Moreover also on land mammals were capturing the open niches left by the extinct dinosaurs. This is called the mammalian radiation because it happened rather fast. This might have caused severe competition for food and habitat among those, especially in estuaria, river deltas or coast line, where a lot of food is found. Apart from finding open niches in the oceans, the early cetaceans also were escaping fierce competition on land by conquering the oceans or even the threat by predators.

 

[Sanoy]

That means that very same spot once was a desert, then a sea floor, then a forest, then a sea floor again, ending up in shallow coast line.

Thank you for doing this. I'm an Old earth creationist but I wanted to ask a question about the above.

So we have this geological striping scenario where clearly this plot of land was all the things listed above. But couldn't the diversity of life we find only in these layers be the fact that it was this type of realm? When this fossil bed became a sea floor wouldn't sea creatures move in and land creatures move out? and then when it dried up and fish became fossils trees moved in and became coal.

 

[Turkana]

When this fossil bed became a sea floor wouldn't sea creatures move in and land creatures move out?

Say you have a plot of land. Land animals and plants are living there and after having lived their lives they die. Some of them die on the right spot where conditions for fossilization is ideal. So fossils of land animals and plants start to accumulate on these sites.

After a while this whole formation subsides due to geological processes. Sea water starts to pour in. Evidently this is mostly a very slow process. We have many areas in the world that are currently slowly subsiding. For instance, Netherlands, where I live, is slowly subsiding - it's measurable and about some 20 cm per century. Also sea levels may rise due to climate change - but also at slow rate.

When the sea has taken over, marine animals live there and die after having lived their lives. Fossilization occurs again and slowly new layers start to build up with only marin fossils to be found.

Millions of years later this area may start to elevate again and the sea resides. At that very moment we will have two geological layers observable on our plot of land: the former terrestrial area with land animals and plants fossils and on top of it a layer of the former sea bedding with marine fossils.

In other words, as we observe a layer with only land animals and plants fossils, this plot of land once was terrestrial. But the layer with marine fossils sitting on top testifies the very same area became a sea floor later.

So the sea gradually pouring apparently didn't wash away the terrestrial fossils sitting in up to tens of meters of sediments.

In your scenario the terrestral fossils, once washed away by the sea water, will end up somewhere on the sea floor, getting mixed up with the marine fossils. But we simply don't observe such mix up.

Your scenario also doesn't work when the opposite happens: when former sea beds elevate and become terrestrial again. But we do not only observe many instances where terrestrial layers are alternated by marine one but also the other way round. And when a sea dries up and becomes land area again, there is no known mechanism that would cause the land animals and plants to "move out".

Or, put in othe rwords, fossils, once buried, do not move out or in. they sit in often hard and solid rock formations.

 

[OldWiseGuy]

In other words, there is no other interpretation possible for these observations: life forms changed over time. Whole new species, complete new classes, orders and even entire phyla of species emerge while they are completely lacking in the older formations. That is called evolution.

There is no other way to interpret this differently.

Ruin/restoration explains it better than evolution. It's the suddenness and completeness of the change in the geologic column that eliminates the possibility of evolution. Evolution implies gradual uninterrupted change. The evidence of sudden cataclysm seen in the geologic record denies this possibility.

 

[John Bowen]

Fossils , DNA , Molecules , atoms .subatomic particles, light waves God said. "Let there be light "

 

[Sanoy]

Say you have a plot of land. Land animals and plants are living there and after having lived their lives they die. Some of them die on the right spot where conditions for fossilization is ideal. So fossils of land animals and plants start to accumulate on these sites.

After a while this whole formation subsides due to geological processes. Sea water starts to pour in. Evidently this is mostly a very slow process. We have many areas in the world that are currently slowly subsiding. For instance, Netherlands, where I live, is slowly subsiding - it's measurable and about some 20 cm per century. Also sea levels may rise due to climate change - but also at slow rate.

When the sea has taken over, marine animals live there and die after having lived their lives. Fossilization occurs again and slowly new layers start to build up with only marin fossils to be found.

Millions of years later this area may start to elevate again and the sea resides. At that very moment we will have two geological layers observable on our plot of land: the former terrestrial area with land animals and plants fossils and on top of it a layer of the former sea bedding with marine fossils.

In other words, as we observe a layer with only land animals and plants fossils, this plot of land once was terrestrial. But the layer with marine fossils sitting on top testifies the very same area became a sea floor later.

So the sea gradually pouring apparently didn't wash away the terrestrial fossils sitting in up to tens of meters of sediments.

In your scenario the terrestral fossils, once washed away by the sea water, will end up somewhere on the sea floor, getting mixed up with the marine fossils. But we simply don't observe such mix up.

Your scenario also doesn't work when the opposite happens: when former sea beds elevate and become terrestrial again. But we do not only observe many instances where terrestrial layers are alternated by marine one but also the other way round. And when a sea dries up and becomes land area again, there is no known mechanism that would cause the land animals and plants to "move out".

Or, put in othe rwords, fossils, once buried, do not move out or in. they sit in often hard and solid rock formations.

Let me put it another way. It's not what I believe but lets say all the old animals existed at once. This plot started as a sea bed so has tons of sea fossils, then it dries up as it moves above sea level. At which point a forest grows, then the land animals that were also in existence at the start wander to their new home.

How do we know from the layers that they came about later rather than wandering in to a new environment?

 

[OldWiseGuy]

Say you have a plot of land. Land animals and plants are living there and after having lived their lives they die. Some of them die on the right spot where conditions for fossilization is ideal. So fossils of land animals and plants start to accumulate on these sites.

After a while this whole formation subsides due to geological processes. Sea water starts to pour in. Evidently this is mostly a very slow process. We have many areas in the world that are currently slowly subsiding. For instance, Netherlands, where I live, is slowly subsiding - it's measurable and about some 20 cm per century. Also sea levels may rise due to climate change - but also at slow rate.

When the sea has taken over, marine animals live there and die after having lived their lives. Fossilization occurs again and slowly new layers start to build up with only marin fossils to be found.

Millions of years later this area may start to elevate again and the sea resides. At that very moment we will have two geological layers observable on our plot of land: the former terrestrial area with land animals and plants fossils and on top of it a layer of the former sea bedding with marine fossils.

In other words, as we observe a layer with only land animals and plants fossils, this plot of land once was terrestrial. But the layer with marine fossils sitting on top testifies the very same area became a sea floor later.

So the sea gradually pouring apparently didn't wash away the terrestrial fossils sitting in up to tens of meters of sediments.

In your scenario the terrestral fossils, once washed away by the sea water, will end up somewhere on the sea floor, getting mixed up with the marine fossils. But we simply don't observe such mix up.

Your scenario also doesn't work when the opposite happens: when former sea beds elevate and become terrestrial again. But we do not only observe many instances where terrestrial layers are alternated by marine one but also the other way round. And when a sea dries up and becomes land area again, there is no known mechanism that would cause the land animals and plants to "move out".

Or, put in othe rwords, fossils, once buried, do not move out or in. they sit in often hard and solid rock formations.

I think the study of "fossilization" should be looked at carefully. Science admits that few organisms are ever fossilized, and then only under certain conditions. Neither the sea floors or land seem to be producing fossils these days. What has changed?

 

[pitabread]

I think the study of "fossilization" should be looked at carefully.

You don't think the people who study fossilization aren't looking at it carefully?

Neither the sea floors or land seem to be producing fossils these days.

Who says they aren't?

 

[Occams Barber]

Thank you Turkana.

I appreciate the effort and thought you've put in to put this explanation together.
OB

 

[OldWiseGuy]

You don't think the people who study fossilization aren't looking at it carefully?

No I don't.

Who says they aren't?

Producing as in processing, not yielding up, although with the floods and mudslides burying people and animals some may indeed become fossils, but we won't know for a couple of thousand years. Anyway the sheer number of ancient fossils due to global cataclysmic events dwarfs any such recent burials. The sea floors haven't seen much of the rapid silt layering needed for fossilization in the recent past either with the possible exception of areas around volcano eruptions.

 

[The IbanezerScrooge]

This is fantastic! Great write up.

How truly unfortunate that it is pointless in these forums as can be seen in responses already.

 

[The IbanezerScrooge]

No I don't.



Producing as in processing, not yielding up, although with the floods and mudslides burying people and animals some may indeed become fossils, but we won't know for a couple of thousand years. Anyway the sheer number of ancient fossils due to global cataclysmic events dwarfs any such recent burials. The sea floors haven't seen much of the rapid silt layering needed for fossilization in the recent past either with the possible exception of areas around volcano eruptions.

So, where did you get your PhD from? How many fossil digs have you been on? I'm sure those are silly questions since you obviously have the academic background and tons of experience with fossils and are well known in paleontological circles since you know so much more than all those so-called "experts."

Right?

 

[SkyWriting]

There creationist posters like Heisonear here who are constantly singing their mantra about "the fossil record doesn't testify for evolution." Unfortunately with a thorough misunderstanding and ignorance of what paleontology actually implies - the scientific discipline dealing with fossils.

So I have to explain paleontology.
I find it kind of peculiar having to explain something to people who apparently feel entitled to criticize stuff instead of getting knowledgable about it first.

There are two different things in paleontology:

1. reconstructing the pedigree-like lineages of ancestor to descendant species. This is about to reconstruct and assign the actual ancestral species that brought forth particular species.

2. providing evidence for evolution by showing there are transitional forms between ancestor and descendant.

They are quite different. While reconstructing pedigree-like lineages involves assigning past species as the *actual* ancestor, so dealing on the species-level, providing evidence for evolution mostly is on a higher taxonomical level and no particular, actual ancestor needs to be assigned. Let me explain:

The task here is to demonstrate the gradual transition in traits between taxa that are mostly (almost always) higher than the level species. For instance, cetaceans share common unique traits that make them "cetaceans". Also artiodactyls (=even-toed ungulates) share *unique* traits that make them "artiodactyls". But it happens that in cetaceans we spot many of the traits that are unique to artiodactyls as well. That already provides an indication about their ancestry, corroborated by the observation that of all extant animals, hippopotamus (an artiodactyl) resembles cetaceans most by DNA comparison.

And it's the gradual change in traits from *artiodactyls* to *cetaceans* we clearly observe in the fossil record. Paleontologists are not even particularly interested in Pakicetus (an ancient land artiodactyl that already exhibited some primitive cetacean traits) being the actual ancestor of extant cetaceans. We can't even know because the very next year we might find a fossil of a sister species of Pakicetus that qualifies even better as actual ancestor of cetaceans.

So, mostly the transition of traits is between higher taxa than species, mostly in families, orders or classes. So while we can't be 100% sure Pakicetus was the actual ancestor of cetaceans, we definitely know that cetaceans, taxonomically spoken an infraorder, evolved from artiodactyls, taxonomically spoken an order. Even more, cetaceans, cladistically spoken, belong to the artiodactyls. They are artiodactyls. Because cetaceans have some traits that are entirely unique to artiodactyls AND we have the fossils that clearly show the gradual transition from artiodactyls to cetaceans.

In a next post I shall spell out how paleontologist figured out that cetaceans are artiodactyls and how many fossils testify of cetaceans having evolved from artiodactyls. Because otherwise this post will become too long.

It always brings a smile to my face when paleontologists find some new transitional, hominid fossil and scratch behind their ears to figure out whether it should be classified as a "pithecus" ("ape-like") or "hominid ("human-like"). Often they fight like cats and dogs. Surely taxonomists must classify new fossil species but the great trouble they have doing so is *because* of the transitional character of such fossils and they actually thus should be happy about their own troubles because fossils that are very difficult to classify are the hallmark of evolution.

The problem is both smaller and larger than you illustrate.

The task is to show one single change.
The assumption is that additional changes will form a complete trail of transition.
The challenge is for creationists to show what would prevent small changes
from accumulating to form an endless succession.

The problem for paleontology is that a perfect trail is logically impossible to find.
The problem for creationists is that a perfect void is logically impossible to prove.

 

[OldWiseGuy]

So, where did you get your PhD from? How many fossil digs have you been on? I'm sure those are silly questions since you obviously have the academic background and tons of experience with fossils and are well known in paleontological circles since you know so much more than all those so-called "experts."

Right?

Can you refute my assertions?

 

[Jimmy D]

Can you refute my assertions?

That fossils aren’t forming today? Of course they are. There are many examples, have you even bothered researching?

Try dodos for a start.

 

[Jimmy D]

Good posts, by the way, Turkana. Very informative.

 

[OldWiseGuy]

That fossils aren’t forming today? Of course they are. There are many examples, have you even bothered researching?

Try dodos for a start.

I granted that already (See post #12).

 

[OldWiseGuy]

That fossils aren’t forming today? Of course they are. There are many examples, have you even bothered researching?

Try dodos for a start.

Perhaps you can provide some information about the fossilization of the Dodo bird, including the scientific requirements for a true 'fossil'.