From: jimruttshow8596
Eric Smith, a researcher at the Earth Life Science Institute in Tokyo and the biology department of Georgia Tech, as well as external faculty at the Santa Fe Institute (SFI), has extensively researched the origins of life [00:00:33]. His background as a statistical physicist from Caltech and the University of Texas has allowed him to apply these tools to various fields, including the nature and origins of life [00:01:08]. He co-authored “The Origin and Nature of Life on Earth: The Emergence of the Fourth Geosphere” with Harold Morowitz [00:01:27].
How Eric Smith Became Interested in the Field
Smith’s interest in the origin of life stemmed from his prior work in high-energy physics, where he focused on phase transitions [00:07:33]. He viewed these transitions as engines and sought to understand how biology might operate under similar principles [00:08:01]. His collaboration with Harold Morowitz at SFI was crucial, as Morowitz had extensive experience in biophysics and physiology and sought laws to explain the biosphere’s signatures [00:08:15]. Morowitz simplified biology to a core where self-organization laws could be applied [00:08:40].
Metabolism First vs. Control First
The concept of “metabolism first” in origin of life proposes that the fundamental laws of small molecule biochemistry were inherited from regularities in geochemistry that existed before the biosphere formed [00:11:01]. The biosphere then developed around these pre-existing regularities [00:11:13].
This view contrasts with “control first,” which adopted Francis Crick’s central dogma of control flow from DNA to RNA to proteins, attempting to trace it back to the beginning of life [00:10:06]. This perspective often placed the “heavy burden” on RNA molecules to act as both genotype and phenotype, which is chemically challenging [00:10:27]. The “metabolism first” perspective suggests that the laws governing early biochemistry are “low-like” and economical, not easily explained by an arbitrary control flow [00:10:47].
Instead, the modern “metabolism first” idea posits that life’s emergence was a cascade of events, with increasingly organized states of geochemistry forming around “paths of least resistance” [00:11:20]. These paths set a template for biochemistry, strong and simple enough to allow for the later emergence of control structures like genes and the central dogma [00:11:47].
The Emergence of the Fourth Geosphere
Harold Morowitz’s insight was to view the biosphere as a “fourth geosphere,” akin to the atmosphere, hydrosphere, and lithosphere [00:13:52].
- Atmosphere: Gas phase, coupled to stellar irradiance [00:13:27].
- Hydrosphere: Liquid state, chemistry of what can happen in water [00:13:18].
- Lithosphere: Solid state, chemistry and physics of solid materials [00:13:10].
Each of these geospheres has distinct chemical and physical states [00:13:10]. The biosphere, as a new state of matter, is dynamically defined with rules distinct from the other geospheres [00:13:58]. It is more unified by its internal processes than by its exchanges with other planetary components [00:14:12].
The origin of life is understood as something that “happens to a planet,” not just on it, leading to the emergence of a biosphere [00:15:10]. This biosphere likely arose from chemical organization at rock-water interfaces, driven by the disequilibrium between the atmosphere and the deep Earth [00:15:38]. As it formed, it became its own robust system with central tendencies [00:15:54].
Potential Sites and Chemical Foundations
Subsurface water alteration zones are considered “very good places to do planetary chemistry” for the origin of life [00:14:40]. Life is driven by electron transfer under voltage differences, and these zones provide the necessary conditions, including electron transfer potentials and catalytic environments [00:14:44].
A planet like Earth functions as a battery, with electron flow from the deep bulk into the atmosphere, driven by processes like solar ultraviolet and x-ray splitting of water, leading to hydrogen escape and oxygen accumulation [00:17:33]. This electron flow predominantly occurs at spreading centers beneath ocean basins, where new crust forms [00:18:27]. These sites offer a controlled, mild chemistry, more akin to biochemistry than high-energy processes like UV light [00:18:54]. Catalytic environments are essential for low-energy chemistry [00:19:10].
Key chemical foundations in modern biology point to the citric acid cycle as a central organizing principle [00:19:39]. This cycle, composed of eleven small organic acids (the largest having six carbon atoms), serves as a carbon fixation cycle and the starting point for synthesizing everything in biochemistry [00:19:42]. Acetic acid (vinegar) is identified as the central molecule for carbon fixation and the deepest part of the biosphere [00:20:21]. Pyruvic acid appears to be the central molecule for the “beginning of everything complicated” regarding amino acids and the genetic code [00:20:47]. These “core linchpins” in biology provide circumstantial evidence for where to focus the search for small molecule chemistry in origin of life and prebiotic chemistry [00:21:04].
Autocatalytic Networks and Energy Flow
Like Stu Kauffman’s work, Smith recognizes that persistent patterns in the biosphere must continually renew themselves, a process known as autocatalysis [00:21:42]. Autocatalysis concentrates diverse environmental materials into specific outputs that then facilitate the conversion of more environmental components into the same organized material [00:22:31]. Biochemistry is replete with autocatalytic cycles that maintain its integration and purity [00:23:01].
However, a distinction is made between Kauffman’s approach, which starts from unstructured combinatorial mediums, and Smith’s focus on the highly structured medium of chemistry itself [00:23:13]. The leading edge in science is to understand collective and cooperative effects and natural feedbacks within such structured systems [00:23:55].
Systems like the biosphere are far from equilibrium, requiring constant energy flow [00:24:18]. While energy flow is important, it is seen as incidental to the material systems involved [00:24:50]. In thermodynamics, energy is one factor determining the available state space, alongside material composition and volume [00:25:29]. By coupling a system to non-equilibrium boundary conditions, energy can flow in and out, allowing for greater system ordering [00:25:58]. This aligns with Harold Morowitz’s view that energy flow through a system tends to organize it [00:27:15].
Beyond Prigogine
Smith suggests going “more radical” than Prigogine’s dissipative systems framework, by exploring the native thermodynamics of any stochastic process driven in any way [00:27:57]. This includes the thermodynamics of rule-based systems like chemical reaction networks [00:28:16].
Current Understanding and Future Directions
Current understanding of the origin of life is fragmented into “little islands” of information [00:29:00].
- Core Biochemistry: Carbon fixation pathways, citric acid cycle chemistry, and common reactions [00:29:09]. This might be an extension of the periodic table expressed by the biosphere’s rigidity [00:29:21].
- Ribosome: An “extraordinary repository of history” concerning RNA, early peptides, and the emergence of translation [00:29:32].
- Genetic Code: Traditionally viewed as a problem of assigning amino acids to codons, Smith believes this is “not nearly dynamic enough” [00:30:04]. The process of becoming biotic is integrated with becoming energetically active and discovering how to fold [00:30:31]. The genetic code likely records how different systems (peptides, RNA) bootstrapped themselves, hitting walls until discoveries in one system opened doors for innovations in another [00:30:57].
The “error catastrophe” problem, where information fidelity between generations must be above a certain threshold for complex evolution, is a major challenge for the emergence of life and evolutionary transitions [00:32:09]. DNA and its complex error correction machinery provide the high-fidelity information substrate for evolution [00:32:23].
Herbert Simon’s arguments about the architecture of complex systems suggest that “all error correction is local” [00:33:19]. Complex systems are plausibly created by assembling building blocks with integral error correction in their subsystems, forming stable intermediate states [00:34:02]. In the origin of life, this means looking for chemical paths of least resistance that naturally regress towards central tendencies, reducing the burden on high-bandwidth control systems [00:35:03].
An example of pre-DNA error correction is substrate-assisted catalysis in RNA and DNA reactions [00:36:12]. Here, the RNA or DNA molecule itself largely defines the catalytic context, simplifying the requirements for surrounding catalysts [00:36:25]. This type of chemistry would have been necessary for the memory systems to become more complicated before complex protein catalysis [00:36:57].
The next frontier in origin of life and prebiotic chemistry is learning “how to explore chemistry” [00:37:12]. Chemistry is a vast combinatorial system that is poorly understood, lacking systematic search methods [00:37:17]. New methods are needed to reason about incomplete claims in this complex domain [00:17:15].
Deep Learning and Chemistry
Emerging deep learning and machine learning approaches are being applied, including work by German chemists on Hamiltonians and by researchers from the University of Southern Denmark and Vienna on “halfway detection” [00:38:39]. These efforts aim to discover and optimize chemical pathways from inputs to desired products [00:39:01].
Ultimately, a key question in complexity theory and evolution of life and emergence of life and complex systems is understanding when and how systems capable of carrying a lot of information become available without being “buried in the heterogeneity of the physical material they’re made of” [01:26:16]. This involves identifying “linchpin steps” that are not combinatorial but create narrow bottlenecks, rejecting enough configurational entropy to allow for a subsequent combinatorial, large, and flat space capable of carrying information [01:25:36].