Another Excuse to Talk about Front-loading

Over on the blog Izgad, Benzion Chinn summarizes a talk from biologist PZ Myers. I would like to quote a excerpt from Chinn’s blog to further help my readers understand the perspective of front-loading and the design of evolution.

Choanoflagellates are single cell organisms that have a lot in common with sponges. We see that they are able to clump together and act as a singular organism. This could be a precursor to multi-celled organisms. The Choanoflagellate possesses things that were once thought to be unique to metazoans; they have receptors such as tyrosine kinases, cadherins and integrins. Trichoplax adhaerens are in a phylum all by themselves. Think of them as micro organic versions of the Blob. They possess genes found in complex brains like ours. In essence our brain is a glorified digestive system. What we think is special about us exists in simpler organisms, serving another purpose.

But evolution can also create things. Nylonase bacteria eat nylon, a product which did not exist before the 1930s. A Japanese nylon factory was dumping waste into the local river and sure enough within a matter of decades the bacteria had evolved to be able to eat nylon. What we have here is a frameshift where a previously useless protein turns out to be useful in binding to nylon. The bacteria were able to exploit this.

In conclusion, nature is not an engineer. The factors that play a role in change are chance, modularity, multifunctionality, incremental tinkering and contingency.

Let me use this to highlight three points.

1. We have seen how Choanoflagellates and Placozoans significantly enhance the plausibility of front-loading. But this excerpt can help us appreciate the difference between the non-telic perspective and the front-loading perspective.

What if genomic data from protozoa and placozoa had confirmed what scientists had previously believed – that tyrosine kinases, cadherins and integrins were indeed metazoan innovations? Would that has damaged the non-telic perspective? Of course not. The non-telic perspective has existed quite comfortably with the notion that such genes were metazoan innovations for decades. Whether the tyrosine kinases, cadherins and integrins pre-existed in protozoa or were invented with the appearance of metazoa does not matter from the non-telic perspective, as either one just as comfortably fits.

For how would the non-telic perspective explain the appearance of tyrosine kinases, cadherins and integrins in metazoan? Exactly as it explains the appearance of nylonase.

Yet the front-loading perspective is not quite as plastic. If tyrosine kinases, cadherins and integrins, which all play crucial roles in metazoan life, has appeared alongside the appearance of metazoa, much like nylonase appeared in bacteria, then the front-loading hypothesis would be seriously damaged. How could a designer design metazoan life through a protozoan state if crucial metazoan-specific information was to pop into existence alongside metazoan emergence because of pure contingency? It is this realization that allowed me to predict we would find metazoan-specific information in protozoan life-forms over seven years ago.

2. “In essence our brain is a glorified digestive system. What we think is special about us exists in simpler organisms, serving another purpose.” This statement really is a classic example of whether the glass is half-full or half-empty. Or, should I say, Rabbit/Duck? A teleologist could look at the exact same data and interpret it as follows:

“In essence, the digestive system was our brain in-waiting. What we think is special about us was long ago in simpler organisms, waiting to exploit its full functional potential.”

However you choose to look at it is a matter of choice.

3. “In conclusion, nature is not an engineer. The factors that play a role in change are chance, modularity, multifunctionality, incremental tinkering and contingency.”

Exactly – nature is not an engineer, so features that echo engineering will catch the attention of our design suspicions. Things like modularity and multifunctionality would allow a designer to make intelligent use of chance and contingency.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s