All my bones are out of joint.
(Psalm 22:14)
Around four billion years ago, as we
Have heard, life first arose. 1 It's not for me
To say exactly how--except that as
A scientist I say it came to pass
By natural means. But what about creation?
Well, that is just religious speculation
Or statement of belief. If it were true
That species were created, how could you
Now prove it? You cannot. Moreover, we
Can't falsify it. It's not science, you see.
But we can falsify the theory that
All life evolved, with just one fossil at
A place it shouldn't be. Find, for example,
A Homo skull in Permian rock: that's ample
To show me Charles Darwin was all wet.
But no such fossil's been discovered yet
And we predict such never will be found. 2
Now one thing I propose to do is pound
A favorite spiel of these creationists
To powder. A creationist insists
No fossil forms exist that we might call
Transitional. That, friends, is folderol.
That life evolved is just as much a fact
As that it now exists, and I'm exact
About it thanks to lots of bones. And don't
Say they were left by Noah's flood. (I won't
Go into that, for the Geologist
Has covered that, and well it's been dismissed.)So life arose--and single-celled it went
Three billion years, till close to that event
In the Cambrian Period that we
Deem so "explosive" it appropriately
Is called the Cambrian explosion. 3 (That
Is really a misnomer, looking at
The time involved: what "suddenly" appears
In point of fact took several million years--
Not long, though, speaking geologically.) 4
Appearing was a wide variety
Of complex, multicellular, marine
Life forms, the first to happen on the scene
With skeletons or hard parts. 5 Common sights
Were little arthropods called trilobites. 6
Creationists have this abrupt appearance 7
Of complex forms out running interference
For their beliefs, but it's a sorry call,
It doesn't gain them anything at all.
The ICR has said that no forebear
Of any of these forms has anywhere
Been found. 8 As Dr. Gish wrote in summation:
The Cambrian Period rocks "cry out, 'Creation!'" 9
Yet Cambrian forms that in his book Gish terms
Creation evidence are things like worms
And shellfish. Higher life forms weren't around,
There was no bird or insect to be found,
No mammal, reptile, or amphibian--
Land creatures make their first appearance in
Devonian times, a hundred million years
After the Cambrian. So what appears
In Cambrian times that even faintly is
Suggestive of the book of Genesis
(Seen by these folks as literal history), 10
In which life's basic "kinds" all come to be
Made in a week? The Cambrian explosion
Lends no support at all to such a notion,
There was no life at all as yet on land. 11
Creationists like Gish deserve a hand:
If Cambrian rocks speak of creationism,
It's quite an act--it's called ventriloquism.We think we know enough to dimly see
What lies behind the Cambrian mystery.
Forms rapidly diversified, spread out--
Adaptive radiation--as about
Them were so many habitats to be
Staked out, all nearly competition free.
It's theorized that photosynthesis,
Producing more free oxygen, helped this
Activity occur. 12 Development
Of hard parts was not something heaven-sent
But naturally selected. And forms that
Were so equipped were much more likely at
A later time to be found fossilized
Than those soft-bodied creatures that comprised
Their forebears. 13Things went swimmingly as fish
Became the first known vertebrates. I wish
There were a fossil intermediate
To show the vertebrate-invertebrate
Connection--but then that would be a creature
Quite simple, and would probably not feature
A skeleton; in short, it wouldn't be
A likely fossil candidate. 14 So we
Are not at all surprised that here we've got
One of those fossil gaps that often spot
The record. But consider now the lancelet
Called Amphioxus, an invertebrate
More like the vertebrates than any of
Its kin; 15 with ocean-bottom sand above
It usually, it lives today, down where
It feeds on strained food particles. If there
Lives a close cousin of some past form that
Was vertebrates' forebear, we're looking at
It in this little beast. We also can
Point out that from the Middle Cambrian
A fossil called Pikaia shows that there
Indeed were forms like Amphioxus where
The forebear lived in geologic time. 16
To study ancient life, it's not a crime
To check out living forms, for all are kin.Let's move along. Let's say we now are in
The period that's called Devonian.
A lobe-finned fish (sarcopterygian)
Possessed a fin that although used to swim
Was in between a fish fin and the limb
Of walking vertebrates (the tetrapods).
While some may think this was a plan of God�s,
This fish was in transition all the same;
Tiktaalik is this creature�s species name. 17
A later creature�s also in between
Fish and amphibian, this form is seen
In Ichthyostega, Carboniferous
The period in which amphibious
Life forms appeared and so proliferated,
Three hundred million years ago (though fated
To be displaced by their reptilian
Descendants). 18We move to the Permian,
Last period of the Paleozoic
Era. Before we start the Mesozoic,
Is there a form transitional between
Amphibian and reptile? Yes, I mean
To say there is: Seymouria by name. 19
Then what are we to make of Gish's claim
That this is incorrect? Can it be true
That this Seymouria's "ancestral" to
The reptiles, when Seymouria appears
Not prior to them but twenty million years
Too late? That's Dr. Gish's question, 20 and
It shows how one can fail to understand
What makes a form transitional. The gist,
As the Paleoanthropologist
Explained, 21 is that it needn't mean "direct
Line of descent." It means we can detect
Transition. The reptilian family tree
Has many branches, and it's plain to see
Seymouria's a branch close to the form
That must have been ancestral. 22 That's the norm
For intermediate fossil finds: we don't
Dig up a "10" but something close; we won't
Hit 10 unless we're lucky. (I'll come back
To, not the absence, but the general lack
Of intermediates--forms smack-dab in
The middle--presently.)Now let's begin
The Mesozoic Era: it's the Age
Of Reptiles, dinosaurs will hog the stage
A hundred and fifty million years. Then they
At last die off, and mammals have their day,
As we've already heard. 23 So here we go
Again: "Is there a fossil form we know
Of that's transitional between reptile
And mammal?" There are many, which we style
The "mammal-like reptiles." (A less prosaic
Name is the therapsids.) They're "mosaic,"
As Dr. Gish described them 24--that's as far
As he would go, denying that they are
Transitional. It makes me want to scream,
Like what he wrote about the monotreme
(The spiny anteater and platypus),
Of living mammals (that's including us)
The form most primitive--the monotremes
Lay eggs as reptiles do. 25 (The bird, it seems,
Descended too from reptiles past; birds too
Lay eggs. But I'll come back to birds.) Now you
Recall Gish on Seymouria, the man
Said that this form was no amphibian-
To-reptile link, it lived too late (the fact
Is that it was a "cousin"). Well, his act
Gish re-performed: the platypus can't be
Ancestral to the mammal line, said he,
Because the platypus shows up too late
In time. Again I'll set the record straight:
No one is claiming that the platypus
Was forebear of all mammals down to us.
The platypus will often drop a hint,
In egg form, of reptilian descent,
And that's the only point that need be made.
(Another egg creationists have laid.)And now for Archaeopteryx, a bird
According to taxonomists. 26 My word,
It looks more like a reptile! You could pluck
It, though, the thing had feathers, so it's stuck
In with the birds. Extinct it was to go
A hundred and fifty million years ago
(Its name means "ancient wing"), a reptile-bird
Transitional form. 27 But guess who has been heard
To disagree. "True bird!" Gish called it. 28 So
What if the thing had teeth? We also know
That some Cretaceous birds had teeth. So what
If Archaeopteryx's wings have got
Clawed fingers? We know of some birds today,
Gish wrote, whose wings have claws. 29 Another way
These people miss the point--the point being:
In toothy birds whose wings have claws we're seeing
Reptilian pedigree. 30Now Archaeop-
Teryx is a good place, I guess, to stop
On intermediates. For we have seen
Already the australopithecine
And Homo habilis and H. erectus,
Transitions used by nature to select us
Who sit here now in Dayton. Let's explore
A nagging question now: why aren't there more
Forms in between than what we find? Well, first
Of all, we know that nature does its worst
To see that few dead things will ever be
Preserved. And this especially we see
With intermediates. Why so? We come
To punctuated equilibrium
(Known also as "punk eek"), a theory that
Eldredge and Gould put forth for getting at
This problem. 31 And some credit, I might add,
They owed biologist Ernst Mayr, who had
Proposed that geographic isolation
Plays an important role in speciation-- 32
That is, the way that new species arise.
Darwin was wrong, they say, to emphasize
Slow change (gradualism). 33 They propose
The following: a band of migrants goes
Beyond the normal geographic range
Of its species and settles; sudden change
Can happen, as mutation, adaptation
Occur in this peripheral isolation--
Abruptly a new species thus appears.
("Abruptly" covers several thousand years
In geologic time.) 34 It's only when
The new species invades what up till then
Was the ancestral range that we will start
To find its fossil form, which for our part
We find "abrupt," for likely we'll not find
The shortlived, isolated form, the kind
That was transitional. Thus speciation
Occurs in bursts, each one a punctuation
In time, which mostly goes along without
Much change at all. So as we dig about,
Found fossil intermediates are few--
Though we've found good ones, as I've said to you.That's punctuated equilibrium.
Though many colleagues buy the theory, some
Don't--there's debate between the gradualists
And punctuationalists. Creationists
Think somehow this helps them, they point and say,
"Aha! See that? They're all in disarray,
Their evolution theory's in real trouble." 35
Pure balderdash! I hate to burst their bubble,
But science--which they seem to know not much
About--thrives on debate, that's why it's such
Exciting work, and that's how we advance. 36My time is up, I thank you for the chance
To talk a bit on paleontology.
I really dig my work, as you can see.