Recently in Aeon magazine
there was an article entitled “Unified Theory of Evolution” by
biologist Michael Skinner. The article starts out by pointing some
problems in Neo-Darwinism, the idea that natural selection and random
mutations explain changes in species or the origin of species. The
article says this:
As interesting as these
examples are, they are merely the tip of the iceberg if you are
talking about cases in which biological functionality arises or
appears too quickly to be accounted for by assuming random mutations.
The main case of such a thing is the Cambrian Explosion, where we see
a sudden explosion of fossils in the fossil record about 550 million
years ago, with a large fraction of the existing phyla suddenly
appearing. Instead of seeing some slow gradual progression in which
we very gradually see more complex things appearing over a span of
hundreds of millions of years, we see in the fossil record many
dramatic new types of animals suddenly appearing.
The other main case of
functionality appearing too quickly to be accounted for by random
mutations is the relatively sudden appearance of the human intellect.
The human population about 1 million years years ago was very small.
This article tells us that 1.2 million years ago there were less than
30,000 in the population. The predicted number of mutations is inversely
proportional to the population size, which means the smaller the
population, the lower the number of mutations in the population. So
when you have a very small population size, the predicted mutation
rate is very low. But suddenly humanity about 100,000 or 200,000
years ago seems to have got some dramatic increase in brain power and
intellectual functionality. Such a thing is hard to plausibly explain
by mutations, given the very low number of mutations that should have
occurred in such a small population.
But Skinner tries to
suggest there is something that might help fix this “too-slow
mutations” problem in Neo-Darwinism. The thing he suggests is
epigenetics. But this suggestion is mainly misguided. Epigenetics
cannot do the job, because it is merely a kind of “thumbs up or
thumbs down” type of system relating to existing functionality, not
something for originating new functionality.
Skinner defines
epigenetics as “the molecular factors that regulate how DNA
functions and what genes are turned on or off, independent of the DNA
sequence itself.” One of the things he mentions is DNA methylation,
“in which molecular components called methyl groups (made of
methane) attach to DNA, turning genes on or off, and regulating the
level of gene expression.” Gene expression means whether or not a
particular gene is used in the body.
The problem, however, with
epigenetics is that it does not consist of detailed instructions or even
structural information. Epigenetics is basically just a bunch of
“on/off” switches relating to information in DNA.
Here is an analogy.
Imagine there is a shelf of library books at a public library. A
librarian might use colored stickers to encourage readers to read
some books, and avoid other books. So she might put a little “green
check” sticker on the spines of some books, and a little “red X”
sticker on the spines of other books. The “green check” sticker
would recommend a particular book, while the “red X” sticker
would recommend that you avoid it.
Perhaps such stickers
would have a great effect on which books were taken out by library
patrons. Such stickers are similar to what is going on with
epigenetics. Just as the “red X” sticker would instruct a reader
to avoid a particular book, an epigenetic molecule or molecules may act like a
flag telling the body not to use a particular gene.
But these little “green
check” and “red X” markers would not explain any sudden burst
of information that seemed to appear in too-short a time. For
example, suppose there was a big earthquake at 10:00 AM, and then at
11:00 AM there appeared a book on the library shelf telling all about
this earthquake, describing every detail of it and its effects. We
could not at all explain this “information too fast” paradox by
giving any type of explanation involving these little “green check”
and “red X” stickers.
Similarly, epigenetics may
explain why functionality that appeared too fast is or is not used by
a species, but does nothing to explain how that functionality
appeared too fast. Epigenetics is making some valuable and
interesting additions to our biological knowledge, but it does
nothing to solve the problem of biological information appearing way
too quickly to be accounted for by assuming random mutations.
Another analogy we can use
for epigenetics is what programmers call “commenting out code.”
Given some software system such as a smartphone app, it is often easy
for a programmer to turn off particular features. You can do what
programmers call “commenting out” to turn off particular parts of
the software. So the following is a quite plausible conversation
between a manager and a programmer:
Manager: Wow, the
app looks much different now. Some of the buttons that used to be
there are no longer there, and two of the tabs have disappeared. How
did you do that so quickly?
Programmer: It was
easy. I just “commented out” some of the code.
Such “commenting out”
of features is similar to gene expression modification produced by
epigenetics, in which there's a “let's not use this gene” type of
thing going on. But the following is a conversation that would never
happen.
Manager: Wow, the
app looks much different now. I see there's now some buttons that
lead you to new pages the app never had before, which do stuff that
the app could never do before. How did you do that so fast?
Programmer: It was
easy. I just “commented out” some of the code.
The programmer would be
lying if he said this, because you cannot produce new functionality
by commenting out code. Similarly, some new biological functionality
cannot be explained merely by postulating some epigenetic switch that
causes some existing gene not to be expressed. That's like
commenting out code, which subtracts functionality rather than adding
it.
I can give Skinner credit
for raising some interesting questions, but he does little to answer
them. The problem remains that biological information has appeared
way too rapidly for us to plausibly explain it by random mutations.
For every case in which
random mutations produce a beneficial effect, there are many cases in
which they produce a harmful effect. Long experiments on exposing
fruit flies to high levels of mutation-causing radiation have not
produced any new species or viable structural benefits, but produce
only harm. We have so far zero cases of species that have been proven
to have arisen from random mutations, and we also have zero cases of
major biological systems or appendages that have been proven to have
arisen from random mutations. So why do our scientists keep telling
us that 1001 wonderful biological innovations were produced by random
mutations?
It's rather like this.
Imagine Rob Jones and his family get wonderful surprise gifts on
their doorstep every Christmas, left by an anonymous giver. Now
suppose there is someone on their street named Mr. Random. Mr. Random
behaves like this: (1) if you invite him into your home, he makes
random keystrokes on whatever computer document you were writing; (2)
if you eat at his house, he'll give you probably-harmful soup made
from random stuff he got from random spots in his house and backyard,
including his bathroom and garage; (3) if you knock on his door, and
ask Mr. Random for a cup of sugar, he'll give you some random white
substance, maybe sugar or maybe plaster powder or rat poison. Now
imagine how silly it would be if Rob Jones were to look on those fine
Christmas gifts on his doorstep, and say to himself: Let me guess
who left these – it must have been Mr. Random!
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