Paul Lindahl’s comments

QUESTION BY QUESTION:

–Q01: Contingency versus determinism in the origin of life/origin of proteins.

I am not an expert in these issues, but would think that origin of life events were as determined/non-determined as events unfolding today. I favour the view that events are not determined prior to their occurrence, but cannot defend this view relative to the deterministic view.

–Q02: Emergence and emergent properties: is life an emergent property?

There is no doubt that life is an emergent property. However, it seems that this can be said for any function composed of multiple variables (the function will exhibit behavior not observed for its determinants).

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

—Q03: Heterotrophic versus autotrophic scenarios.

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

I strongly favor the chemiautotrophic scenario in which metabolism preceded proteins and nucleic acids. Explaining why would take too long here.

–Q04: On the origin of catalytic cycles

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

See my paper (Stepwise Evolution…) for my perspective.

–Q05: On the origin of specific macromolecular sequences

I am not a synthetic chemist and don’t have an informed opinion on this.

–Q06: About the RNA world

Due to the problems described, I feel that the RNA world model is untenable.

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

–Q08: Proto-cellular world (a)

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

I think that the first living entities were autocatalytic surface metabolists. They grew (spread) on surfaces without lipids membranes, DNA or proteins. These components first appeared as waste products, until they be part of the autocatalytic system, at which point they became incorporated as part of the “cell”. At some point, the cell, containing DNA/RNA, proteins etc, became encapsulated by a lipid membrane, and then lifted off the surface. Eventually, a cell cycle developed.

–Q10: Life as unity or confederacy

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

I view society as a high-level living organism analogous in some respects to a surface metabolist that grows by spreading. Social relationships are analogous to chemical relationships between cells in a multicellular organism.

–Q11: Ecology and individuality

See answer to previous question.

–Q12: Defining the very origin of life

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –I agree that the term means different things to different people, and that this is detrimental to making progress in this field. The term “origin” seems to imply that life was created in an instant rather than as an extended process. The “evolution of life” would capture this better. One important issue is how complex systems could evolve without DNA/RNA.

–Q13: About the anthropic principle (AP) Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

Attributing events to a cosmic purpose does sound difficult/impossible to test scientifically. To be fair, there is little in origin-of-life issues that can rise very far above the level of speculation, casting doubt on whether any of the associated hypotheses are testable science.

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

–Q14: On the entire field of the origin of life

Questions for san sebastian <!– @page { size: 8.27in 11.69in; margin: 0.79in } P { margin-bottom: 0.08in } –>

Somehow I do think the ideas for the origin of life are “better” now than they were a few decades ago, and far better than the ideas of 50 years ago, but it is hard to quantify this.

Note added: After dabbling around these issues ~ 10 years ago, I decided that the field was too speculative for much (any?) progress to be made. So I switched from thinking about the origin of life to trying to define the concept of life better. In my view, this requires a stronger {mathematical/physical/chemical} perspective than is currently in the field. Thus, we have been developing mathematical minimal whole-cell models that self-replicate. I regard this field as being in its infancy and of potential importance within the broader field of Computational Systems Biology. As we develop better/more detailed/more complete models of whole cells with realistic behaviours, perhaps we will learn something about life’s origins in the process.

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




%d bloggers like this: