How Evolution Is Scientific Part 2: Accurate Predictions

Uploaded by shanedk on 19.01.2009

Welcome to part two of this series,
rebutting the Answers in Genesis--excuse me, Creation Ministries International--
article claiming that evolution is not scientific.
Part 2 covers their second claim:
that evolution makes no accurate predictions.
They begin with a typical creationist quote-mine of Darwin,
saying that the lack of transitionals is the biggest problem with his theory.
They then repeat the lie that no intermediate fossils have been found.
Moreover, it's clear that they don't even understand what a scientific prediction is.
For an example, let's look at the fossil Tiktaalik.
This is a half-fish, half-tetrapod. It has fish gills and scales, and tetrapod ribs, neck, and lungs.
Its limbs and ears are halfway between those of fish and tetrapods.
By all accounts, this is a transitional form, exactly what anyone would expect.
But the most important thing about this fossil is not how perfectly transitional it is,
but where and how it was found.
An expedition led by Edward Daeschler and Neil Shubin went to Ellesmere Island
to see if they could find a fish-to-tetrapod transitional.
The reason why they went here is that they knew that this area corresponded
to where the coastline was during the Devonian period.
They also knew what strata corresponded to the Devonian.
Tiktallik was there, in the exact area and in the exact strata predicted by the scientists ahead of time.
That was the only reason they were even in that area to begin with.
But transitional fossils weren't the only--or even the biggest--hole in Darwin's knowledge.
The biggest problem Darwin had was that he had no mechanism
for heritable traits to be passed from parent to child.
Everyone knew there had to be one,
but no one knew what it could be or how it worked.
The prevailing wisdom was Lamarckian evolution, which said that
changes in heritable traits result from acquired characteristics.
According to Lamarck, giraffes, for example, evolved longer necks
through their attempts to stretch and reach fruit and leaves higher up the tree.
Whereas Darwin theorized that some giraffes just happened to acquire slightly longer necks by accident,
and that these giraffes had a better chance of survival than ones with shorter necks.
The biggest problem was the dilution of traits.
If an organism did have a chance beneficial mutation, it would have trouble passing it on,
as its children would only have the mutation at half strength, and their children at a quarter, and so on.
After generations of breeding, the effect of the mutation would peter out.
Evolution just cannot work in such a manner.
In modern terms, evolution predicts these traits to be digital, not analog.
The trait would either be passed on to the next generation in full, or not at all.
Darwin's theory thus predicted three things:
In order to test whether newly-acquired traits are diluted,
Gregor Mendel in the 1860s performed experiments on peas and cataloged their various traits.
He discovered that both forms of a trait--say, tall stalks and short stalks--
could assert themselves fully in future generations.
The traits did not blend together.
Then, James D. Watson and Francis Crick's monumental discovery of DNA
solved the problem once and for all.
Inheritable traits were stored in genes, and these genes were passed on fully from parent to child.
Moreover, the chemicals that make up genes could mutate,
and change themselves into a stronger or weaker version of the gene,
or even alter its function entirely.
Further, these mutations occurred regardless of the needs of the life form,
not only confirming Darwinian evolution but falsifying Lamarck.
If this had turned out any other way, evolution would have been in trouble.
But the genetic story was far from over.
In the 1960s, it was observed that humans have 23 pairs of chromosomes.
However, the other members of the great ape family have 24 pairs.
How could this be possible if we share a recent common ancestor with them?
How could we have lost an entire set of chromosomes?
Chromosomes are collections of genes, and they're not collected in any organized fashion.
Genes are distributed throughout the genome pretty much at random.
So any given chromosome is going to contain vital genes for the development of the organism.
If any of the pairs of chromosomes were to be lost,
the organism would never even develop into an embryo.
Evolution was in trouble.
There was one prediction that evolution could make:
that the chromosome pair was not lost, but fused with a different chromosome.
The chromosomes themselves have no function other than containing the genes,
so it doesn't matter if a particular group of genes is all in one chromosome or divided out into several.
How could this prediction be tested?
First of all, the genetic sequence of this fused chromosome would have to be a perfect match
with two ape chromosomes laid end-to-end (minus the usual genetic differences between them).
But there's more.
At the ends of every chromosome are telomeres, book-ending the genes the chromosome contains.
In the middle of every chromosome is a centromere,
which the cell uses to move the chromosome during cellular reproduction.
A fused chromosome would have telomeres in the middle,
and again these telomeres (as well as the ones on the end) would have to match
the telomeres in the corresponding ape chromosomes.
Moreover, there would have to be not one, but two centromeres,
and one of the centromeres would have to be deactivated.
This is a very specific, detailed, and nuanced prediction,
and if it turned out to be any other way, evolution would be a theory in severe crisis.
Thirty years later, sequencing of both human and chimpanzee genomes
allowed the scientists to test this prediction once and for all.
And what they found matched the predictions of evolution precisely.
Human chromosome #2 is a fusion of two ape chromosomes.
Everything matches just as evolution said it should.
The idea that the human chromosome should arrange itself precisely like this
without there being any relation to apes is too ridiculous to even consider.
It not only confirms evolution, but spells the death of creationism and intelligent design.
If this isn't good enough for you, then consider one more prediction of evolution
regarding endogenous retroviruses, or ERVs.
Retroviruses are viruses that reverse-transcribe their RNA into DNA sequences
and integrate them into the host's genome.
By doing so, they trick the host's cells into reproducing the virus.
If such a retrovirus inserts itself into a germ cell (a sperm or ovum),
the virus's genes can be passed on to the next generation.
If a subsequent mutation destroys the virus's function,
the new DNA sequence can be passed through the generations with no ill effects.
Here is where evolution makes a prediction:
since we share a great lineage with chimpanzees,
we should have many ERV sequences in common:
not only from the same retrovirus, but also inserted into precisely the same position in the genome.
Since we are less closely related to gorillas,
the ERVs we have in common with them should be a subset of the ones we have in common with chimpanzees.
And so on.
We also should have our own unique ERV sequences commensurate
to the amount of time since our last common ancestor.
Guess what? This is EXACTLY what we find.
To see this in more depth, watch this cdk007 video giving more details:
The short answer is that the chances of such an incredible match with evolutionary prediction
coming about just by the random activities of retroviruses
are 2.0 x 10^138.
So small as to be too ridiculous to even THINK about proposing.
Some creationists counter that the insertion of retroviruses may not be completely random.
But even if the possible locations are only 1% of the genome,
that still makes a probability of 4.3 x 10^119.
No help at all.
As you can see, evolution does make testable predictions--
and very detailed and nuanced ones at that.
And the evidence we have discovered has matched them beautifully.
This could only be the case if evolution were true.
So, does evolution make accurate predictions?
In Part 3, we will look at their lame attempts to refute evolution with logic.