Darwin's Dilema Script

8/11/2019 Darwin's Dilema Script

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DARWIN'S DILEMMA Subtitle master/ FINAL 10/17/2009

1. Narration

An ancient mystery is etched upon these mountains. Astory of primordial oceans and

prehistoric life.

Of creatures stranger than fictionand the controversy that has surrounded them for

more than a century.

2. Narration

Buried among these majestic peaks are glimpses of an event that transformed the

planet in a moment of geological time.

Compelling evidence, etched in stone, that challenges long-held assumptions about theorigin of animal life on earth.

3. Narration

Today, most paleontologists think that complex animals first appeared on earth about

530 million years ago during a geological period known as the Cambrian.

But early in the 19th

century, little was understood about this seminal event in the

history of life

4. Narration

In 1831, the renowned geologist Adam Sedgwick began to excavate theCambrian

rock strata in northern Wales.

He was assisted by Charles Darwin, a recent graduate of Cambridge University.

5. Narration

For the young Darwin, the fossils embedded in the Cambrian shale were an intriguing

curiosity.

But, at 22, he lacked the perspective to appreciate their full significance.


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6. Narration

Natural selection, the theory of evolution, and the Origin of Species, all lay years

ahead. So he couldnt imagine that the stones beneath him held a mystery he would

never resolve.

7. Narration

It was a mystery Darwin would ponder into old age and then pass on to future

generations. The mystery of the Cambrian explosion.

8. Simon Conway Morris

The Cambrian geological interval is just great in terms of the fossil record because

thats when animals effectively first colonize the earth.

Its a very exciting time and, by and large, scientists like to work in vividly,

interesting areas where theres a hum about the whole thing, and thats very much thecase with the Cambrian at the moment.

9. Narration

Simon Conway Morris has devoted his career to the study of evolution and the early

history of life.

Morris has staged expeditions on four continents and surveyed the intervals of

geological timewhile focusing his attention on the Cambrian period and evidencefor the sudden emergence of animals in a veritable explosion of life.


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10.Simon Conway Morris

The Cambrian explosion is exactly what it says it is. Its an explosion. Now, not an

explosion in terms of pieces of animal flying all over the place. Actually, when

biologists talk about an explosion what they mean is, effectively, an enormousdiversification-what we call a radiation. So we have during the Cambrian what

appears to be the abrupt appearance of animals,

Were filling the barrel with lots of different types of organisms. But were alsoinventing nervous systems, were inventing eyes, were inventing how to move

quickly. So the whole world is speeding up. Its an event where in many respectseverything changes forever.

11.Narration

More than a century ago, a stunning window to the Cambrian explosion was openedby a series of discoveries made in western Canada.

In 1886, the Canadian Pacific Railroad reached British Columbia and the KickingHorse valley. For the first time, eastern and western Canada were linked by a 2500

mile steel artery that opened the Rocky Mountains to tourists, adventurers, and men of

science. Among them was the geologist, R.G. McConnell

Earlier in the year, McConnell had heard reports of a shale bed on the flank of Mt.Stephen, just outside the town of Field. Railroad carpenters, who had explored the

area, said it was filled with stone bugs.

In September, McConnell climbed the mountain. To his amazement, he found

unmistakable imprints of prehistoric life on most of the shales in the bed. McConnellwas standing in an ocean of fossilized trilobites.

12.Simon Conway Morris

Trilobites are iconsof the Cambrianand there are billions of trilobites high up on theshoulder of Mt. Stephen. One reason for that is that as they grew they periodically

threw off their old skeleton and made a new skeleton. So basically they made many

fossils throughout their individual lives.


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13. Narration

McConnell collected hundreds of these fossilsand sent many of them to other

scientists for examination.

News of his work soon reached the offices of the United States Geological Survey and

Charles Doolittle Walcott, a leading expert on Cambrian paleontology.

Walcott was fascinated by McConnells reports, but had to wait almost 20 years forthe opportunity to conduct his own research. Finally, in 1907, as the newly appointed

secretary of the Smithsonian Institution, he boarded a train for western Canada

14. Narration

Walcott spent two summers at Mt. Stephen collecting fossils and surveying the

geology of the area. Yet, despite his success here, he knew his exploration of thesemountains was only beginning.

Lookingoutacross the Kicking Horse valley to the Burgess Pass, Walcott set hissights on a corner of the Rockies untouched by the hammer and pick of any geologist.

This is where he would move his expedition.

15. Narration

On August 30, 1909, Walcott led his team below this ridge

15 miles north of Mt. Stephen. There, legend holds, he stopped to examine a pile of

shale that blocked the narrow horse trail. As he picked up a slab, the geologist noticed

a faint, but well-defined fossil he had never seen before. A delicate lace crab he laternamed, Marrella.


He knew plenty and plenty about the Cambrian. He was an expert on the Cambrian,

he published many papers. And when you see this little Marrella, its only about acentimeter in length, you get out your hand lens, and you suddenly see that this is, you

know, it shouldnt be there. This is soft-bodied effectively. And Im sure he realized

in seconds what it meant. He must have.


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17. Narration

In the summer of 1910, Walcott found a fossiliferous band in the ridge. After blasting

a quarry, the geologist and his family unearthed thousands of exquisitely preservedspecimens from soft-bodied animals previously unknown to science.

He called the site the Burgess Shale.


There in Burgess Shale (especially the lower level, which Walcott first exploited), thepreservation is miraculous. Its astonishing. We find trilobites of course, but we find

many, many other sorts of arthropods, almost none of which are ever found in a

typical Cambrian assemblage. So we can treat them effectively as being soft-bodied.They have almost no chance of being fossilized in normal circumstances.

19. Narration

Geologists believe that the animals of the Burgess Shale were buried quickly and alive

by an avalanche of sediment that created an air-tight tomb and prevented the decay of

soft body parts like eyes, legs, and internal organs.


Now, in the animal Marrella, very often there is sort of what we call a dark stain. AndI find this very intriguing because that dark stain evidently is the body contents

oozing out. So in other words the animal is beginning to decay, and then something

stops it.

On many of the arthropods we have the most delicate branches, and you can see every

single fine hair along them. Quite astonishing. Many antennae going out like that.


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In particular instances, we have some worms, so we can see the outside of the body.

We can see various things at the front, which enable the worm to burrow through the

sediment. But then you look at the animal itself and you can see this sinuousreflective line, and of course you say--oh, thats the gut. Thats the alimentary canal.

And then in certain cases you actually look at one part of the alimentary canal and you

can actually see food inside it. Shellfish which its swallowed.

It is a remarkable insight into a fossil youd never expect to be fossilized.

22. Narration

The Burgess Shale was once part of a massive reef in the Pacific Ocean-a haven for a

menagerie of life that thrived at the edge of what is now the North American

continent.

Throughout long periods of geologic upheaval, tectonic forces elevated these rocks,

and the fossils they bear, more than 7000 feet above sea level.

Here, the basic body plans of major animal groups that still exist today (and many

others, now extinct), made their first appearance in the fossil record so suddenly that

biologist Richard Dawkins noted: it is as though they were just planted there, withoutany evolutionary history.

These fossils gave science its first detailed look at the biology of the Cambrian seas.

With computer animation, we can now bring that world to life.

23. Narration

Like something out of science fiction, Opabinia was a creature so bizarre it still eludesclassification. While its five eyes watched for predators, the animal captured its prey

with a grasping claw.

First described in 1899 (from a fossil found on Mt. Stephen), Wiwaxia has alsopuzzled scientists.

This mysterious Cambrian animal was covered with overlapping scales and may havefed by scraping microscopic particles off the sea floor.


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27. Jonathan Wells

He would have a branching tree pattern. And for a long time you would only have

that one species, and then it would eventually branch into two species, and then more

species, and different families, and orders, and classes.

And in Darwins thinking, given enough time, those differences accumulate,

especially under natural selection, if the environment changes. Those differences

accumulate to the point where a thousand or a million generations from now yourgreat, great, great, great grandchildren will be a different species .

28. Paul Nelson

So, it is both logically and almost aesthetically a unifying picture, a unifying image,

that pulls together the whole of life on earth. And for many biologists, that kind ofunification is very important.

29. Narration

Common descent and natural selection became the twin pillars of modern biology and

Darwins branching tree of life, its foremost icon.

Yet, despite the clarity and detail of his argument, Darwin acknowledged a problem

that defied explanation: the Cambrian fossil record

30. Darwin character voice

The distinctness of specific forms, and their not being blended together byinnumerable transitional links, is a very obvious difficulty.

I allude to the manner in which species belonging to several of the main divisions ofthe animal kingdom suddenly appear in the lowest known fossiliferous rocks.


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31. Paul Nelson

When Darwin was writing the Origin of Species, it was well known at the time that the

first fossils of animals appeared suddenly without precursors in the geological record.

So there was a deep conflict between what his theory told him to expect to find(namely an abundance of transitional forms going back to that common ancestor for

the animals) versus what was there in the fossil record.

32. Narration

Darwin knew that if his theory was true, the older rock strata directly beneath the

Cambrian layer, should reveal a progression of fossils connecting simple earlier forms

to complex animals (like trilobites), through a trail of incremental steps and failedbiological experiments.

Such evidence would document the trial and error process of natural selection.

33. Paul Nelson

But Darwin says in the Origin, Where are these transitional forms? Theyre not

there in the fossil record. What we see instead are fully formed, discrete groups.Now, thats a world-class puzzle for someone like Darwin


And so its very, very striking, and one can see why Charles Darwin was so puzzled

by the Cambrian explosion because he had enough knowledge even at the time torealize that deep in the earths history you just didnt find the animals.

35. Darwin character voice

If my theory be true, it is indisputable that before the lowest Cambrian stratum was

deposited, long periods elapsed and during these periods of time, the world swarmedwith living creatures.

To the question of why we do not find rich fossiliferous deposits belonging to these

assumed earlier periods prior to the Cambrian, I can give no satisfactory answer.


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36. Stephen Meyer

Darwin was deeply troubled by the Cambrian explosion. He called it an inexplicable

mystery. But he wasnt about to abandon his theory and, instead, proposed that the

animals just looked like they appeared suddenly because he thought that the fossilrecord was incomplete.

37. Darwin voice

I look at the natural geological record, as a history of the world imperfectly kept, and

written in a changing dialect

Of this history we possess the last volume alone, relating only to two or three

countries. Of this volume, only here and there a short chapter has been preserved; and

of each page, only here and there a few lines.

38. Paul Nelson

So Darwin argued, well, perhaps paleontological discovery-digging through the

rocks-needed more time. That the transitions were out there. That not enough

collecting had occurred. Not enough sampling, if you will, of the fossil record on

earth. And, given time, those transitions would turn up

39. Narration

Three decades after Darwins death, Charles Walcotts historic work in the Canadian

Rockies did nothing to fill the gaps in the tree of life or the fossil record.

Walcott uncovered the remains of Cambrian animals unknown to Darwin. And each

demanded its own unique progression of evolutionary ancestorsa trail of evidence

that did not exist in the Burgess Shale.


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40. Paul Nelson

Walcott realized that the Cambrian explosion of life was an even bigger problem than

Darwin imagined. So, in an attempt to defend evolution, he reached back to Darwins

explanation of an incomplete fossil record.

41. Stephen Meyer

Like Darwin, Walcott thought that the Cambrian explosion was an illusion. He was

convinced that the fossils were there. They were just inaccessible to scientific

discovery. And he expected that they would eventually be found buried someplacedeep beneath the oceans.

42. Narration

For decades, Walcotts hypothesis was widely accepted, but untestable. However,later in the 20th century, new technologies led to empirical conclusions.

43. Stephen Meyer

Once the oil companies started to drill offshore, they brought up what are called drillcores. And inside the cores were hunks of sedimentary rock, and some of the rocks

contained fossils. But none of them were made by animals that lived before theCambrian explosion.

44. Narration

Since the 1960s, scientists have also used radioactive minerals, and evidence of

changes in the earths magnetic field, to analyze and date undersea sediments.From extensive surveys, they have created this digital map that defines the age of theseafloor.


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50. James Valentine

In the late Precambrian and at the Cambrian boundary, were seeing the rise of larger

organisms that had fluid skeletons and strong muscles and they could burrow and they

could crawl around. And as time goes by, we begin to see on the ancient sea floorsediments, trails, little squiggles where a small worm was crawling along. They look like

squiggles left by little tiny worms today. So from near 600 million years to 543 millionyears (more or less 50 or 60 million years), what we mostly see, as far as living kinds

of animals, are these little squiggles.

51. Narration

There is also evidence that near the end of the Precambrian, the oceans were inhabited

by jellyfish, sponges, and the mysterious Ediacaran fauna


If you go to immediately before the Cambrian, then actually you find something

extremely puzzling because you get large organisms, large fossils, and these are calledthe Ediacaran assemblages. And they have been one of the great headaches for

paleobiology, and also for evolutionary biology. Why? Well, because basically some

look like animals. But other ones dont look like animals at all.

53. Paul Nelson

Some of them look like air mattresses, quilted air mattresses. Others look like fronds.

Theyre not plants, but they kind of have that appearance.


So these Ediacaran assemblages are bag-like. They are what we call sessile. Most of

them didnt move, or if they did they probably moved pretty slowly. It looks a rathersleepy, a rather dozy world.


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55. Narration

Whether the Ediacarans were actually animals or plants is still uncertain. But late in

the Precambrian, they disappeared from the earth. Then, long after their extinction,everything changed in a geological instant.

In a spectacular burst of creativity, the basic blueprints for most of the animalkingdom exploded into being. And for the first time, biologically complex structures

like compound eyes, spinal cords, articulated limbs and skeletons appeared on earth .

To understand the speed of the Cambrian Explosion, imagine the history of lifecompressed into a single day.

56. Jonathan Wells

If we imagine the whole history of life on Earth taking place at one 24-hour period

(the current standard estimates for the origin of life put it at about 3.8 billion yearsago), lets say, four billion. So if we then start the clock-our 24 hour clock

six hours, nothing but these simple single celled organisms appear. The same sort

that we saw in the beginning.

12 hours, same thing. 18 hours, same thing.

Three-quarters of the day has passed and all we have are these simple single celled

organisms.

Then at about the 21sthour, in the space of about two minutes boom! Most of the

major animal forms appear, in the form that they currently have in the present. Andmany of them persist to the present. And we have them with us today.

Less than two minutes out of a 24-hour period. Thats how sudden the CambrianExplosion was.

57. Narration

Since Darwin, excavations on every continent have revealed the magnitude of theexplosion of life-an event that was clearly global in scope.

Most recently, several discoveries in southern China have fascinated science and

deepened the Cambrian mystery.


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58. Narration

In 1984, one of the most important finds in the history of paleontology was madeoutside a small town in Chinas Yunnan province.

While surveying this mountain near Chengjiang, Hou Xian-Guang unearthed

Cambrian fossils older, more diverse, and better preserved than any ever discovered.The condition of the Chengjiang fossils was so remarkable Hou said, it appeared as if

the animals were alive on the wet surface of the mudstone.


The fossils theyve collected are stunning, really beautiful to look at.

60. James Valentine

Theyre brightly colored, stained with iron and probably other kinds of minerals so

theyre kind of golden looking or kind of reddish and they really stand out from the

rather tan colored background of the rocks. And theyre just beautiful. Soaesthetically, theyre wonderful.

61. Jonathan Wells

Many of them are soft-bodied. No hard parts, no skeletons, no shells, just soft bodied,

and yet theyre exquisitely preserved. So you can see the Cambrian explosion in greaterdetail than you can anywhere else in the world


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62. Narration

In the early 1990s, reports of the Chinese fossils were released to the rest of

the world. At the University of San Francisco, marine biologist Paul Chien

followed the news.

63. Paul Chien

What drew my attention was, in fact, a couple of articles published in Peoples

Daily. The official paper for the communist party in China announced that the

Chengjiang fossils drew the attention of scientists worldwide.

Peoples Dailyreported that this find actually challenges the theory of

Darwins evolution.

And then, towards the end of 95, Time Magazine(on December 4th),

had this

front cover story about animal big bang, which talked about Chinese great leapforward in science. That really solidified my interest. I said this is something

really big. I want to get to the bottom of this. One day I will stand in front of

the fossil site myself and find out whats going on.

64. Narration

Since 1996, Paul Chien has made several trips to southern China to conduct hisown investigations.

65. Paul Chien

When you talk about the Cambrian explosion a lot of people find it fascinating

and so forth. But when you get into the topic, generally there are two

reactions-people who love it and people who kind of avoid it.

The Cambrian explosion does challenge the traditional idea of gradual

evolution of animals, because they all seem to appear all of a sudden and the

problem is, how do they explain it?


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66. Narration

Paleontologists have determined that the Chinese fossils were older than those

excavated at the Burgess Shale. Yet, anatomically, they were often even morecomplex.

This discovery also confirmed that previous estimates of an explosion lasting20-40 million years were much too long.

67. Paul Chien

The time period that we figured it took the animals to be established in the

ocean in those days took probably ten million, five million years. So this istruly an explosive event in the scientific terms.

What we are seeing is a quantum jump. And this quantum jump has no

explanation

68. Jonathan Wells

The Cambrian explosion was so short that it is below the resolution of the

fossil record. It could have happened overnight. So, we dont know the

duration of the Cambrian explosion. We just know that it was very, very fast.

69. Paul Nelson

As the interval of the Cambrian explosion is compressed (in other words, asthe time available shrinks), the challenge to evolutionary theory grows because

the differences in form that have to be constructed very rapidly are much more

dramatic. Its going to pose a real and, I think, fundamental challenge to

evolutionary mechanisms.


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70. Paul Chien

From what I saw, the Chinese scientific community, as a whole, seem to be rather

progressive about this. They are convinced by the evidence that the Cambrian

explosion is real. And they see it as a challenge to Darwinian theory. They are honestabout this. Therefore, they are thinking about how to explain this outside of the

Darwinian thoughts.

71. Narration

The Chengjaing fossils provide the most inclusive picture of the Cambrian explosion

yet documented. And directly beneath them (in Precambrian shales), another chapter

in the history of life is written in the rocks.

72. Steve Meyer

Theres another amazing find thats been made in China. Paleobiologists havediscovered litte, tiny microscopic sponge embryos in the layers of rock just beneath

the layer that documents the Cambrian explosion.

73. Narration

These embryos were soft-bodied animals, some fossilized 60 million years beforethe

Cambrian explosion.

74. James Valentine

There are eggs and embryos which are preserved in thin crusts of mineralized material(a phosphatic material on ancient sea floors) which suggest that the chemistry of the

sea water in those days was somewhat different than it is today.

Because this method of preserving fossils disappears during the Cambrian and its not

around today. So were lucky that we have these thin crusts with little tiny fossils inthem


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75. Stephen Meyer

This is highly significant because one of the most popular explanations for the missing

Precambrian fossils is that the Precambrian animals were too soft and too small to

have been preserved.

76. Narration

Since 1999, Paul Chien has studied fossil embryos and helped develop techniques to

analyze their structure.

77. Paul Chien

By treating them with acid you can actually remove the rock and isolate the embryos.

And then youve got a round pebble-like or sand grain like samples. And then welooked through some tiny little ones, and larger ones up to one millimeter in size. And

we found about the range between 500 and 800 micrometers,we have mostly sponges.

And then I stopped breaking up these balls and tried to start looking inside. And withthe help of the electron microscope, I was able to see the detailed sub-cell structure

within these embryos.

78. Narration

Chiens work on these fragile remnants of Precambrian life raises an important

question.

79. Stephen Meyer

If these lower strata can preserve an embryo. If they can preserve a soft microscopicembryo-then why couldnt they have preserved the larger ancestral forms that

supposedly evolved into the Cambrian animals?

In other words, if you can preserve something as fragile as an embryo, why couldnt

you, in the same strata of rock, preserve the immediate ancestor of a hard shelled

trilobite?

80. Jonathan Wells

So, the idea that the fossil record is too damaged to provide us with at least a general

picture-that idea just doesnt wash.


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81. Narration

During the past 150 years, fossil hunters have searched the earth for the manytransitional links Darwins theory requires.

82. Paul Nelson

If I sent you on a treasure hunt and said, what I really want it this, youre going out

and look for this, whatever it happens to be. Well, if you come at the fossil record

with a Darwinian expectation of an abundance of transitionals, thats whats going toget you a professorship. You find those transitional forms.

So, all over the world in countless outcrops, people have been looking for those formsthat would capture the major transitions in the history of life.

83. Narration

This search has extended from the walls of Grand Canyon to the shores of the Irish

Sea. And as countless specimens have been excavated, one question endures:

How complete is the Cambrian fossil record?


I think the Cambrian fossil record is surprisingly complete, I think it may be more

complete than we realize. The reason for that is for instanceif you look at the

stratigraphy of the worldif I go and collect Cambrian rocks in Wales and findcertain fossils, if I then go to China I dont find the same species, but I find the same

sorts of fossils. If I go into carboniferous rocks, I go to Canada, theyre the same as

what I find in this country. So theres a clear set of faunas and floras which take us

through geological time. The overall framework is falling into position.


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85. Paul Nelson

Theres no question that if you dig and sample more, youre going to find new kinds

of fossils. But, generally speaking, the fossils that we find, fall into groups we already

knew about. When you see that, what I think nature is telling you is youve got apretty good sample of the history of life on earth. The groups that you already

established are the ones that capture the new fossils.

86. Paul Chien

To the paleontologists, the lack of intermediate fossils is well known. Some people stillthink that if you look long and hard enough you will eventually find them.

But I think most of the paleontologists that I have been in contact with, would not

have that hope very high. They simply feel that we have looked long and hard enoughand that they are not there, they are not there.

87. Darwin Character voice

The difficulty of assigning any good reason for the absence of vast piles of strata rich

in fossils beneath the Cambrian system is very great. The case at present must remaininexplicable and may be truly urged as a valid argument against the views here

entertained.

88. Narration

In 1831, three months after his first exposure to Cambrian geology, young CharlesDarwin embarked on an expedition that would influence the development of his theory

of evolution.

As naturalist aboard the HMS Beagle, Darwin sailedto the Galapagos Islands, 600

miles off the coast of Ecuador. For five weeks, Darwin explored this remote island

chain-home to an extraordinary assembly of animals. Here, the idea for his tree of lifewas planted.

According to Darwin, as one form of life morphed into another, new species arose.And, as they gradually branched apart, larger differences in form emerged.

Eventually, evolution produced an even greater level of disparity-the distinct body

plans of new phyla.


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89. Paul Nelson

Phyla are abstract categories that bring together basic features that unite large groups

of animals. So you can think about a phylum as a group of organisms that all share a

basic architecture.

90. Jonathan Wells

Based on the body plan of the animal we divide animals into these major groups.

Theres vertebrates-the backbone and soft bodies outside the bone structure.There are arthropods, which have a hard skeleton on the outside and a soft body on the

inside. These are the insects and the crabs. Theres the echinoderms, which are the

sea urchins and starfish.

91. Paul Chien

Sea stars are different from jellyfish, different from worms and different from crabsand lobsters. So each group has their unique features that make them very different

from the next group.

92. Narration

The stability of these forms in the animals that exemplify the distinct phyla, contradict

Darwins vision of an interconnected tree of life.

93. Paul Nelson

The phyla dont blend, imperceptibly, one into another. Arthropods, for example

didnt evolve from chordates. Mollusks arent the offspring of sponges.

Instead, a phylum is, in effect, as different as it can be from another phylum. So, how

did those differences arise? If one reads The Origin of Species, its clear that Darwinscaught in a bind.


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94. Steve Meyer

Natura non facit saltum. That was Darwins famous Latin phrase which means,

nature takes no sudden leaps. In fact, Darwin went on to say, that if you found

evidence of saltation, of sudden appearance in the fossil record, that would besomething like evidence of special creation.

95. Narration

One of the most striking examples of a sudden leap in nature is evident in the number

and stability of new animal body plans that first appeared during the Cambrianexplosion.

96. Steve Meyer

One of the other remarkable things about the Cambrian explosion is that a hugepercentage of the total number of phyla that have ever existed on earth, all appear

within a very narrow window of time.

97. Paul Nelson

Its a defensible statement, that most of the major animal body plans are present in theCambrian explosion. Thats where they first appear.

98. Paul Nelson

Imagine a graph, if you will, of the appearance, over time, of phyla. In Darwinspicture, youd haveonethen twothen four, perhapsthen eight. A gradually

increasing curve of the number of phyla growing over time.

99. Steve Meyer

What you actually have in the fossil record is a sudden spike in the number of phylathat appear during the Cambrianand then a few that trickle in across the rest of

geologic time

This kind of discontinuity is radically at odds with the Darwinian picture of the history

of life.


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100. Paul Nelson

The pattern we see is the major body plans present at the beginning and that theorganisms that we know today, fall into one or another of those major body plans.

They dont gradually increase over time.

101. Narration

The sudden appearance of animal body plans deepens the Cambrian mystery in

another way. The Darwinian model predicts that as new biological forms evolved(simple to complex), they developed gradually-from the smallest differences in

classification to the largest. Or, from the bottom-up.

102. Jonathan Wells

Darwins idea was that given enough time evolution would lead to new species, new

families, orders, and eventually phyla. And only after millions and millions ofgenerations do you end up with the several dozen phyla that we see around us now

days. That would be the bottom- up pattern predicted by Darwins theory.

103. Paul Nelson

Now, the other picture is top-down. The top-down picture says the primary

differences are original. Theyre there right at the start.

When you find mollusks in the fossil record, or the arthropodsboom, there they are,

with the major differences present, right at the beginning. So the upper levelarchitecture is, top-down, present, right there.

104. Narration

This top-down pattern of biological development can be compared to the

development of human technology.


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105. Stephen Meyer

If you look at any major invention, like the automobile, for example-the basic body

design is set in place from the very beginning.

Youve got four wheels, a chassis, a drive shaft, two axles. There are certain basic

features of all automobiles that have persisted since Ford and Benz got the whole thing

going over a century ago.

106. Narration

In the decades that followed the introduction of the automobiles basic framework,designers and engineers have created thousands of variations on the original theme.

But regardless of differences in size, color, and chassis design, the foundational body

plan remains consistent to its original form.

107. Stephen Meyer

And an interesting thing about the fossil record is that theres a similar top-down

pattern evident in the history of life. The basic body plan of the arthropod phylum hasa segmented torso, jointed legs, and an exoskeleton all of which arose suddenly at the

beginning of the Cambrian explosion. And today, we still see the continuity of thisoriginal plan, this foundational idea, in over a million species of animals.

108. Narration

This top-down pattern looks nothing like the predictions of Darwins theory

109. Jonathan Wells

Darwins theory is that there is a tree of life, where you have one organism diverginginto many other organisms and big differences appearing at the top.

What we really see is, from here up. This does not exist in the fossil record.

If I were to using a botanical illustration it would be a lawn, with separate blades of

grass sprouting independently of each other. And those would be the phyla. Now,

within each phylum there is subsequent diversification. But even there, I dont see the

branches connecting that would make them a tree of life.


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110. Paul Nelson

Darwin was caught in the grip of a deep dilemma. The fossil record showed him onething. His theory told him something else.

He comes to an impasse at this point and he says, "If this pattern holds, it is a genuine

argument against by view." I think 150 years later, we have added a great deal moredetail to the picture, but I think the basic problem is still unsolved.

111. Stephen Meyer

How did these new animal body plans and fundamentally new forms of life come into

existence? This was the mystery Darwin set out to solve. But everything weve

learned in biology over the past 50 years has brought this mystery back with avengeance.

How do you explain the origin of the Cambrian animals seemingly out of nowhere?This isnt just a problem of explaining the absence of evidence in the fossil record.

Its also a problem of explaining everything we know about life, right down to thelevel of molecules and cells.

112. Narration

The biological structure of a Cambrian trilobite was as complex and sophisticated as amodern crab. Its organs included a brain, gut, heart and compound eyes. Each organ

was constructed from specific types of cells. Each cell type was made from dozens ofspecialized protein molecules. And each protein was assembled from a four-letter

chemical code in a section of DNA called a gene.

113. Stephen Meyer

Now, for the evolutionary process to transform a simple Precambrian organism like a

sponge (with 4 or 5 cell types) into a Cambrian trilobite (with at least 10 times asmany different types of cells)thats a huge leap in complexity. And to make thatleap, youd need a vast amount of new genetic information

But, where did this information come from? Thats the central mystery of theCambrian explosion.


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114. Narration

According to Neo-Darwinism, new proteins are constructed by the dual mechanismsof genetic mutations and natural selection. As the genetic instructions for building

proteins are copied, an occasional error can alter their contents. If these accidental

revisions prove beneficial to survival, they are selected or preserved and passed on tofuture generations.

Over eons, these small changes accumulate and new proteins, cell typesand even

Cambrian carnivoresgradually evolve into existence.

115. Stephen Meyer

Richard Dawkins, the famous Oxford evolutionary biologist, has illustrated how the

Darwinian mechanism works using the metaphor he calls climbing Mt. Improbable.

116. Narration

From the front side, the mountain is a sheer cliff that could never be scaled in one

giant leap. For Dawkins, this represents the impossibility of creating a complexanimal, by chance alone. Yet, Dawkins also envisionedan alternative route up the

backside of Mt Improbable. A long, gradually sloping trail of small steps leading all

the way to the summit.

117. Stephen Meyer

According to Dawkins, thats how youd climb the mountain. And thats also howyoud build a Cambrian animal-one small step at a time.

What chance alone cant accomplish in one blind leap, natural selection canaccomplish through the cumulative effect of many small incremental steps.

118. Narration

In theory, each step corresponds to a small unit of biological change-a new gene and

its protein product. But do mutations and natural selection have a reasonable chance of

producing even one protein in the time available? Since 1992, molecular biologist

Doug Axe has examined this question.


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119. Doug Axe

Theres a story thats being told and theres an appeal in the case of Darwinism to

random mutation and natural selection as being, in vague terms, the mechanism. But if

you look at the detail, what kind of mutation can accomplish these transitions?

And there, its important to realize that the one area where we can really nail this

down is at the single protein level where you can actually measure it. And if you look

at protein structures, to get a substantially new protein fold is prohibitively difficult.

120. Narration

Each of the thousands of different proteins in nature is actually a chain made from aspecific combination of 20 different amino acids. The sequential order of thesechemical building blocks is crucial, for if they are arranged correctly, the chain folds

into a functioning three-dimensional molecule. But if the amino acids are incorrectly

assembled, no protein will form.

If proteins are indeed rare among the possible sequences of amino acids, what are theodds that mutations would stumble upon a functional combination of chemicals from

the vast number of alternatives?

To find out, Axe randomly altered the structure of an enzyme protein comprised of

150 amino acids.

121. Stephen Meyer

Youve got a protein 150 amino acids long, then youve got 20 to the 150th

power ofpossible ways of arranging the amino acids. Out of all those possibilities, how many

are functional and how many are gibberish?

122. Doug Axe

If you do the experiments and you analyze how much information is required to get anew protein fold, its just far beyond what you can get by random mutation and natural

selection.


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123. Narration

How far beyond? Axe published his findings in The Journal of Molecular Biology.

He determined that among all of the possible amino acid combinations, the probability

of generating just one short protein by mutation is roughly 1 in 10 to the 74th

power.

Or, one chance in a hundred trillion trillion trillion trillion trillion trillion

124. Stephen Meyer

To put that in context, there are only 10 to the 65 atoms in the entire galaxy. So tobuild a new functional protein, by selection and mutation (within the time allowed for

the Cambrian explosion), what youre essentially having to do is equivalent to a

blindfolded man looking throughout the entire galaxy for one marked atom.

So what were talking about is searching for a tiny, tiny needle in an enormoushaystack. And having a very limited time to search.

125. Doug Axe

So on the question of something like the Cambrian explosion, there does not appear to

be any way that unguided random mutations can accomplish what needs to be

accomplished to explain new functional proteins.

And certainly by extension, wherever in the history of life you would need to havemultiple new protein folds the probabilities multiply. So theres no reason to think that

this is plausible.

126. Narration

But the inability of random mutations to generate new genes and proteins is only part

of the problem. For, the origin of Cambrian body plans demanded more than newgenetic information.

127. Richard Sternberg

A lot of the information for specifying an Anomalocaris, a Trilobite, what have you,

does not reside at the DNA level.


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128. Jonathan Wells

The body plan, as far as we know, is not in the DNA.

129. Narration

While DNA carries the instructions to manufacture proteins, it cannot alone, assemble

them into cell types. Or arrange cell types into new tissues and organs. Or tissues andorgans into body plans.

Instead, the formation of body plans ultimately requires another level of information

stored somewhere in the three- dimensional structure of the egg cell and the embryo

Instructions that direct the development of complex animals from fertilized eggs.

With computer animation, we can observe this intricate process.

130. Narration

As an egg cell begins to divide and differentiate, a network of biological commandsorchestrates the development of an arthropod.

After several stages of division, dozens of new cells align against the outer membraneof the egg. And then, cued by a chemical signal, they start their migration toward

targeted areas in the embryo where they will gather and develop into a mature

organism.

131. Narration

The cells steadily increase their numbers and align, like members of a marching band,

into patterns that will form the tissues and organs, head and legs of the growingembryo.

132. Paul Nelson

That happens by a process of cell specification and differentiation where cells arecommitted, irreversibly, to performing particular roles. Youre going to give them

different jobs to do. Youre going to be part of the locomotary system of thisorganism. Youll be an eye, youll be a gut, and so forth. To me thats an absolutely

astonishing process, but it works. And what it builds you is different kinds of

organisms depending on the instruction set thats provided


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So there is an organismal blueprint-an ultimate point that the embryo hones in on, and

is attracted to, and eventually embodies.

134. Jonathan Wells

That foresight, that preordained outcome, is built into the embryo


When you talk about these early developmental sequences in Anomalocaris, and

Opabinia, or what have you, youre talking about information in the broad sense,codes, specifications, entailments, implicationsthat are orders of magnitudebeyond

anything we can currently conceive. Its so off scale that youve left that line of

impossible by chance a long time ago.

136. Narration

The volume and complexity of information that controls the development of a body

plan is staggering. And its location in the cell stands as perhaps the ultimate

challenge to the neo-Darwinian scenario of random mutation and natural selection.

137. Steve Meyer

We know that much of this higher level information required for building new tissues

and organs and body plans isnt found in DNA. That means that you can mutate DNAindefinitely without respect to probabilistic limits, without respects to time and

number of trials, and youre never going to get the kind of form and structure you need

to build a new organism.

DNA is simply the wrong tool for the job and no amount of time is going to overcome

that limitation. That has a really devastating implication for the Neo-Darwinian

mechanism.


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138. Narration

If the Darwinian mechanism cannot explain the origin of the information necessary to

produce the Cambrian animals-is there any other cause that can?For more than 20 years, Stephen Meyer has explored this fundamental mystery.

In August 2004, Meyer published several of his conclusions in a peer-reviewed journal

affiliated with the Smithsonian Institution. His essay triggered a firestorm ofcontroversy that jeopardized the career of the journals editor, evolutionary biologist

Richard Sternberg. But, why did a technical paper on the origin of animal body plansevoke such heated response?

139. Stephen Meyer

For many people, the problem with the paper was simply my conclusion. I not only

argued that the Darwinian mechanism could not explain the origin of the new form

and information that arises in the Cambrianbut, I also argued that there were critical

features of that explosion that pointed to the reality of a designing intelligence in thehistory of life.

140. Narration

Since his years as a graduate student at Cambridge University, Meyer has worked todevelop a scientific case for intelligent design. A case based on a standard method of

reasoning used by both Darwin and the famed 19th

century geologist, Charles Lyell.

Lyell insisted that the best explanation for an event in the remote past was a cause,known from our experience, to produce it. A presently acting cause-one now in

operation

141. Stephen Meyer

The present is the key to the past. That was Lyells dictum. Its standard historical

scientific methodology. If youre trying to reconstruct what happened in the remote

past we should let our present experience of cause and effect guide our search for thebest explanation.

142. Narration

This reasoning helped focus Meyers conclusions about the origin of information.


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143. Stephen Meyer

The light came on for me because I realized its not that hard. What youre looking

for are causes, which are known to produce the kinds of effects youre trying to

explain.

And I asked myself the question: what is the cause now in operation that produces new

information-whether its digital code, or whether its hierarchical information in theform of a blueprint? Where does that kind of information come from?

Well, we know from our experiencefrom uniform and repeated experience (which isthe basis for all scientific reasoning about the past)-that information always comes

from an intelligent source.

And so when we find information in the Cambrian animals, when we realize that large

infusions of new information are required to build those animals, the most natural

thing, the most logical thing to conclude is that those animals owe their origin to anintelligent source.

That the information required to build them, in turn, must have come from anintelligence.

As Ive reflected on this over the years, Ive realized that the same reasoning thatapplies to the origin of biological information, also applies to the origin of the other

key features of the Cambrian explosion.

144. Narration

The sudden top-down appearance of the phyla during the Cambrian explosion defies

the simple-to-complexpattern of development that Darwin predicted.

145. Paul Nelson.

In Darwins picture, youd have little differences accumulating to big differences. Thetop-down picture turns that on its head.


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146. Stephen Meyer

You find first you get new phyla, and then you have some variations on those themes

over time. But the new form, the big differences appear right from the beginning in

the fossil record.

Now, if you consider the possibility of design, you realize that that pattern makes

perfect sense because we see in our own history of technology the same pattern of top-

down appearance in new forms.

147. Douglas Axe

Youre always working from your high level objective to your details in order to

accomplish the high level objective.

148. Paul Nelson

Only intelligence can visualize a complex end point and bring together everything

thats needed to actualize that end point.

149. Narration

The body designs evident in the Cambrian animals have continued to appear indifferent species throughout the history of life. Yet though these species share

common body plans, they are not connected by a continuous line of intermediatematerial forms.

150. Steve Meyer

The continuity that explains that consistency of form through time is the continuity ofan idea. And so when we see in the fossil record the same basic idea popping up overand over again, that suggests that a mind has played a role in the origin of that form, of

that body plan organization.


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151. Narration

Designed systems also display another distinctive feature: they are comprised of a

network of complex, and precisely organized, component parts.

152. Douglas Axe

You could speak of these in terms of a nested hierarchy. You have the very high levelparameters that specify the whole project goal. Below that you have layers and layers

of more detailed parameters that are needed in order to complete the whole project.

153. Narration

As an example, resistors, capacitors, and transistors are each made from specifically

arranged materials. These components are then assembled to form integrated circuits.

Circuits are arranged to build computersthat are then arranged into networks ofcomputers.

154. Stephen Meyer

So at each level there is a specificity of arrangement thats provided in turn by the

intelligent designer, the engineer that keeps the whole system working. Well, what

you have in biology is something very similar.

155. Narration

In living systems, genes code for proteinswhich are organized to form distinctive

cell typeswhich are arranged to form tissues and organswhich are assembled intobody plansincluding the plans that arose during the Cambrian explosion.

156. Stephen Meyer

We know of only one cause in the entire universe that can produce that kind of

hierarchical arrangement of form, and structure and information, and that cause is

intelligence. This is the kind of thing that minds do, but natural undirected processes

dont.


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157. Paul Nelson

Evolution works very slowly as Darwin saw it. With lots of failed experiments along

the way and one would expect, that over millions of years, as sediment was beingdeposited, that you would capture some of those experiments, some of those linking

groups leading to the trilobites that he knew all about

158. Stephen Meyer

And so the absence of those forms is profoundly mysterious. But from the standpoint of

intelligent design its not mysterious at all because we know that intelligent agents canbring things into existence that didnt exist before, because they had an idea. They had a

blueprint in their minds that they realized in their creative activity.

So, theres no need to tinker through millions of years of evolutionary history if you can

actualize a plan at a discrete moment in time. And thats exactly what appears to have occurredin the Cambrian explosion.

159. Darwin Character voice

If numerous species, belonging to the same genera or families have really started into

life all at once, the fact would be fatal to the theory of descent with slow modificationthrough natural selection.

160. Narration

No aspect of the natural world troubled Charles Darwin more than the Cambrian fossil

record and the explosion of life it revealed. Today, many of the details of this

remarkable chapter in the history of life still await resolution.

Yet modern paleontology, genetics, and embryology have cast new light upon the

Cambrian mystery and the origin of complex life on Earth.


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161. Douglas Axe

If you have very different forms of life that appear in a very short, and a very brief

time period with respect to the earths history, it certainly has the appearance that

design problems were solved, and that they were solved elegantly, and that they were

solved in very many instances.


When these forms appeared it wasnt just one or two rickety, hanging on the edge

forms. It was a panoply, a manifold of different body types.

It does have an explanation, if you regard in addition to matter and energy in the

universe, information as being just as important, if not more important. And that iswhere I think intelligent design theory comes into play.

163. Paul Nelson

I think, to build an animal, the kind of process the evidence requires is a process thatcan look into the future and bring everything together, to actualize something like a

trilobite, or a chordate, or a mollusk, or the other different forms that we see in the

Cambrian explosion.

Its going to be a process that has foresight. Its going to be a process that can

visualize complexity. Its going to be a process indistinguishable from intelligence.Thats not natural selection. Thats design.

164. Steve Meyer

The postulation of intelligent design not only helps to resolve a longstanding scientificmystery, but it also speaks to a larger question

Because what we see in the origin of complex life on earth is not evidence of just anundirected process. Instead we see evidence that life was designed, that life was

plannedthat it was intended.

Darwin's Dilema Script

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