Gavest thou the goodly wings unto the peacocks?
or wings and feathers unto the ostrich?
(Job 39:13)
What's a theory? A statement we can test,
However indirectly. On it rest
Predictions, that is, "This must be," we say,
"If that is given. B will follow A."
If what's predicted doesn't follow, then
The theory's falsified (as we heard in
The Physicist's remarks). 1 A theory so
Well tested it's considered "true"? I know
Of one: "All living things have by descent
From simpler forms evolved." No time is spent
Debating that now in biology;
The hypothesis is so well tested we
Consider evolution to be fact--
As much as is Earth's roundness--inexact
Though we may be about the mechanisms.
Look at the fossils, at us organisms,
Both dead and living proof. We don't suspect
The theory's wrong because what we'd expect
To find if it's correct is what indeed
We find. It's in that sense that we proceed
To make predictions. 2 Let us test a few.Prediction number one: if it is true
That life evolved, then fossil forms should be
In evolutionary sequence, we
Should find that older forms are simpler ones,
The younger more complex. That's how it runs
All through the record, just as we'd predict.
Creationists would say that we've been tricked
Into believing that this fossil order
Is evolutionary, for the sorter
Was really Noah's flood. 3 One well can see
That we are leaving science, though, when we
Start trying to explain things by the Bible,
Especially when that will make us liable
To disregard the explanation that
Is natural. What am I driving at
When I say "simpler forms to more complex"?
Well, reptiles like Tyrannosaurus rex
Evolved from some amphibians, from fish
The latter came, and though some may not wish
It so, we mammals came from reptiles. We
Thus say the trend's toward complexity.Prediction number two: if it is true
That life evolved from one form--I and you
And every form related to each other--
All living things should look like one another
In some descending order. 4 Once again
We find what we'd predict. We all contain
The same genetic code (as we have seen), 5
Amoebas, humans, and all in between
Are chemically alike in that regard.
Take Vertebrata embryos: they're hard
To tell apart (the Vertebrata's what
All animals, including man, who've got
Backbones are called). Now of common descent
That clearly seems to be another hint.
Developing beyond the embryo,
Each species will of course proceed to grow
Uniquely, based on which genes are expressed,
Which proteins are at work. 6 I can attest,
However, to work of molecular
Biologists, who find more similar
The DNA in species closely kin
Than is the DNA in species when
The kinship is more distant. DNA
In humans and chimpanzees, by the way,
Is ninety-six percent identical;
The evidence is therefore chemical
That chimps are people's closest living kin,
As all along we figured, seeing in
Behavior and anatomy the clues. 7
The same holds true for proteins: we can use
Amino acid sequences to see
How closely species are related. We
Can take a protein called a cytochrome
(The "c" type), for example: as we roam
Along its sequence, there's one hundred-plus
Amino acids, and we find in us
Close cousins man and chimp that A to Z
The sequence is the same, whereas we see
The sequence differs somewhat in the horse
And even more in tuna fish, of course. 8
What good is all of this? Well, these are tools,
These DNA and protein molecules,
Used by molecular biologists
As bones are used by paleontologists:
They use them to construct a family tree. 9
And both tree types, that based on chemistry
And that based on the fossils, very well
Agree.The naked eye, of course, can tell
To what extent in gross anatomy
Species resemble one another. We
Apply the term homologous ("agreeing")
To structures that are similar by being
Of shared descent. Thus fishes have paired fins,
Kin to the leg pairs in amphibians,
Reptiles, and mammals, for those legs evolved
From fins of fishy forebears. (Not involved
Are structures that have happened to converge;
Thus bird and insect wings did not emerge
From a common forebear, homology
Does not apply, the similarity
Is in the adaptation.) 10Those who preach
Creationism say we're wrong, they teach
That all resemblances, all family trees
Suggesting there is kinship by degrees,
Are due to God's use of one grand design 11
In all that he created down the line--
The concept of a "Great Chain of Being"
That dates back to the Greeks. 12 One man agreeing
Was Carl von Linne (Linnaeus his
Name Latinized); what made him famous is
The system he devised to classify
All forms of animal and plant life by
The use of binomial nomenclature
(Giving all organisms found in nature
Generic names, like Homo, followed by
Their species names, like sapiens). That's why
He's called "the father of taxonomy"
(A taxon is a group of forms). Now he
Was a creationist, for he believed
That every form of life should be perceived
As specially created, one more link
In God's Great Chain of Being. Now we think,
Of course, that in the pattern he discovered
In life forms he unwittingly uncovered
Inherited relationships. 13 Linnaeus
Would surely be surprised if he could see us
Now use his system as clear evidence
That life evolved! But I will not commence
To deal yet with "intelligent design,"
Creationism's new "scientific" line. 14
(The "argument from design" is centuries old
And long has been refuted--Hume, I'm told,
Did quite a job on that, so I assume
We'll hear from the Philosopher on Hume.) 15
Design I'll speak of, but there's more to be
Predicted first.Prediction number three:
If truly life evolves through adaptation
By natural selection, the duration
Of time involved about four billion years,
Enough mutations, strifes, and new frontiers
Would have occurred by now to guarantee
Life would exhibit much diversity
Despite its common origin. Well, that
Is really understating it! Look at
The vast array of forms, variety
So stunning that species are found to be
Innumerable quite literally. More than
A million and a half so far has man
Named and described as living species, though
As many as ten million--we can't know
Exactly what the number is--now share
This Earth. 16 Yet all these living can't compare
Numerically with species that have gone
Extinct. Old Elbert Hubbard must have known
This when he said, "Life is just one damned thing
After another!" 17Species well might sing
A plaintive song. Prediction number four:
The same long struggle that has led to more
And more diversity should also lead
To countless forms' extinction. We can read
The fossil record, that gives us a hint
Of the degree to which forms came and went
Throughout the past; they far outnumber those
That now survive. Lord Tennyson well chose
His words: nature is "red in tooth and claw." 18
It's estimated that extinction's maw
Has swallowed more than ninety-nine percent
Of all the species that have ever spent
Some time here. 19 That's a pretty gruesome rate.
O curséd fruit! (Creationists relate
That all the death with which life has to grapple
Is just deserts: one couple ate an apple.) 20Prediction number five: geography
Should make a difference in biology,
To wit, closely related species should
Be found in close proximity, 21 while good
Space in between should mean that species are
More distantly related. 22 Groups may far
Migrate; all migrants must adapt, and so
Should differ more the farther that they go
Away from one another. That is what
We would expect and that is what we've got.
Not only groups, whole lands are known to shift.
I'm sure you get my continental drift.
(Geologist, that's yours.) 23 With barriers
Like drift and mountain-building, change occurs
As isolation leads to separate ways.
That's why we find down under nowadays
The kangaroo, it's nowhere else, and why
There are no hummingbirds around to fly
Outside of the Americas. 24 The poor
Creationists have one whale of a chore
In trying to explain life's distribution.
They claim all creatures died in an ablution
Called Noah's flood save pairs of every "kind"
Aboard an ark. (You have to keep in mind
That Genesis is taken literally
As being actual ancient history
By ICR, the creation think tank that
Heads this whole movement.) From Mount Ararat
These pairs, creationists believe, spread out
To populate the Earth, all in about
Four thousand years or so, no matter how
Slow moving or how isolated now,
For all Earth's natural barriers. They say
"The hand of God" helped creatures find their way
Around the world. 25 That's science? They ignore
The problem, ICR folks don't explore
How this occurred. Biogeography's
A subject that "creation science" flees. 26And now, with our prediction number six,
Creationists are really in a fix.
The subject is design--if that's the word.
Creationists believe, as you have heard,
That everything reflects the order and
Design bestowed by a Designer's hand.
Neocreationists (Bill Dembski's one,
There's also lawyer Phillip Johnson) shun
The c-word though. To what do they resort?
"Intelligent design" (ID for short). 27
They credit Michael Behe with the key,
It's "irreducible complexity"
In forms like the bacterial flagellum. 28
But if we can't yet say (I hate to tell 'em
This) how this or that evolved, that's not
To say it therefore was designed. We've got
Ideas how the flagellum came to be, 29
But we should not pursue it? Seems to me
That this design they're selling is perhaps
Some damaged goods, the old "God of the Gaps":
Explaining things in nature by reliance
On acts of God, instead of using science
To find out natural causes, is to see
God have to keep retreating more as we
Fill in each gap in knowledge. 30 (They don't claim
It's God, though, their "designer" has no name,
Or so they say.) What should we call this credo?
"Creationism in a cheap tuxedo." 31
The ID cause was set back (it�s not over)
By Judge Jones in Kitzmiller versus Dover,
Who ruled that ID isn�t science, and
Has a religious viewpoint, to be banned
In public school science classes (at least those
In Dover, Pennsylvania--how it goes
Across the land we�ll see). 32 Look out for this:
Some call for "critical analysis
Of evolution" now in public school,
While they deny such language is a tool
To introduce ID. 33So they have picked
Design not close to what we would predict,
And therefore it should not be hard to see
Who's closest to the truth. So here's what we
Predict: if life by natural selection
Evolves, no form will ever reach perfection
Nor will it work like something engineered
By a divine intelligence. It's weird
To think a panda's "thumb" (which thanks to Gould 34
Folks see now is a form that had 'em fooled)
Was God-designed; the panda for a thumb
Has had to use a wrist bone, which seems dumb
As engineering--why no thumb? Adapt,
That's what the panda had to do, for apt
Is not always the right word for selection,
It's not a process leading to perfection,
It makes do with what is at hand.The eye,
Now that's an organ often cited by
Creationists as well designed. Come on!
To start with, it did not arise full blown;
Like other complex organs, it arose
From simpler forms that forebears had, and those
From even simpler forms, until we're back
To light-sensitive cells. 35 It shows a lack
Of planning, too, there's quite a flaw that tells:
The retina's photoreceptor cells
In vertebrates point not toward the light,
They're wired in backwards! 36 Jared Diamond's right:
A camera designer who made a blunder
Like that would be fired on the spot. No wonder!The eye, the panda's thumb, those are but two
Examples, I could sit all day with you
And speak of organs poorly engineered.
Indeed no living form has yet appeared
To falsify what we've predicted. Show
Me one and I'll concede that it is no
Contraption, it's a marvelous design
That only could derive from the divine.
Why do amphibians have legs that are
So clumsy? 37 Is it possible that far
Back in the past those legs were fins? Indeed,
That's just how life adapts: when there's a need,
A part gets modified, improvisation 38--
Not some new part, some tailor-made creation--
Is what comes into play, and so we find
No part is ever perfectly designed
But often seems just modified enough
To do the job required. That's how forms tough
It out.Some structures have no use at all
("Vestigial organs" is what we would call
A few of these), 39 like tiny legs on whales,
Like genes for teeth in chicks, and like the tails
Some humans have been born with. 40 Tell me why
A male has nipples. 41 Such things mystify
Based on creation, like divine mistakes,
But evolutionary theory makes
Them simply understood. Genes normally
Inactive but retained, occasionally
Become reactivated, get recast
Out of the evolutionary past--
Why else might newborn Johnny have a tail?
God made it when he made legs for the whale?
Male nipples weren't "designed," it's plain to see
They're scraps, spare parts from embryology,
Where some things differ soon and others late
As male and female differentiate.
Life's stuck with poor design, much uselessness.
Creation wouldn't augur such a mess,
But evolution does. By now it's clear,
I trust, the latter is no engineer,
It is a "tinkerer." 42 Maladaptation,
Genetic side effects, reactivation
Of long inactive genes--it's no surprise
With evolution that such things arise.Some forms are worse than useless. An example
That Charles Darwin wrote about is ample:
Ichneumon larvae, parasites that feed
Inside live caterpillars. Do we need
Such forms as that? Darwin could not persuade
Himself that any kind Creator made
Ichneumon larvae, or designed a cat
To play with mice. 43 And I can tell you that
I'm not persuaded either. What could cause
Such things then? Nature's blind, amoral laws.If species were designed, then why have they
So poorly fared that all have died away
Save one percent? We know that adaptation
Cannot save all, but one would think creation
Would be designed to see that most do well.
I cannot buy the story they would tell
That living things must struggle, die, and grieve
Because old Adam listened to his Eve
And ate that fruit. 44 No, that's theology
(They're welcome to it), not biology.I'll say, concluding, I can't see creation,
While evolution tracks with observation
So well, with all that we'd expect to see,
It is as much a fact as there can be.
Epilogue to the Biologist's Tale
"Well I predict," said the Astronomer,
"We'll later hear from the Philosopher
On nature's amorality." 45"Indeed,"
Said the Philosopher, "we have a need
For values. Nature simply is; we go
Outside of science, then, to seek to know
What's 'good' and 'evil.' It's my moral view
That parasites are evil." 46"It's mine too,"
Said the Astronomer, "but let us visit
The moral issues later. Whose turn is it?"The Paleoanthropologist said, "May
I add a word first? I'd just like to say,
On babies born with tails, that surgery
To cut off human tails is easily
Performed. The one known case of nonremoval
Was when the parents wouldn't give approval,
They made good money showing their tailed child." 47"As parasites, ichneumon larvae's mild
Compared to that tailed baby's mom and dad,"
Said the Astronomer. "That's pretty sad,
They made their own poor child the butt of jokes.
Whose tale is next? No pun intended, folks."