CSH Workshop

Trade-offs between thermodynamic cost, intelligence and fitness in living organisms

11th-12th March 2024

slides available at: slides.com/jankorbel

Welcome!

About the workshop

1) At the scale of an individual organism (be it a unicellular creature, a single cell in a multicellular organism, or an individual in a eusocial species), what are the inherent physical constraints relating to thermodynamic efficiency, fitness, and intelligence?

2) At the scale of natural selection, how should the theorems of evolutionary biology be modified to account for the trade-off between the thermodynamic costs of performing computation and the fitness benefits of computations?

Two main questions

How do we answer them?

• Participants will give talks related to the main questions
• We will have a discussion after each talk
• We can also use the breaks for discussions
• At the end of the workshop, we will have a round table session

Recommended reading

https://www.dropbox.com/scl/fo/t2089fl9prh12m2c23yw1/h?rlkey=80pai6ifgkhu1qi8b3vuksh1b&dl=0

General rules for talks

Workshop schedule

Monday

   9:00 –    9:30 Registration
   9:30 – 10:00 Welcome
10:00 – 10:30 David Wolpert
10:50 – 11:10 Coffee break
11:10 – 11:40 Valentin Riedl
12:00 – 14:00 Lunch Break
14:00 – 14:30 Edgar Roldán
14:50 – 15:05 Coffee Break
15:05 – 15:35 Robert Foley
15:55 – 16:25 Tom Ouldridge
 

Tuesday

   9:00 –    9:30 Coffee
   9:30 – 10:00 Sosuke Ito
10:20 – 10:40 Coffee break
10:40 – 11:10 Gonzalo Manzano
11:30 – 12:00 Peter Stadler
12:20 – 14:00 Lunch break
14:00 – 14:30 Chris Kempes
14:50 – 15:05 Coffee break
15:05 – 15:35 Riccardo Rao
15:55 – 17:00 Round table

Brief introduction

Can every participant briefly introduce themself?

Please mention briefly:

• Your scientific background
• What are you currently working on? 
• Why are you interested in the workshop topic?

Why do we think using a physics theory (stochastic thermodynamics) in biology can be useful?

• Energetics is a crucial aspect of all living systems

• All living organisms must be efficient in energy consumption

• All organisms are, by definition, far from thermodynamic equilibrium

• Novel results in non-equilibrium physics can be useful in understanding the energetics of living organisms and their evolution

• There are many similarities between physical and biological systems

Similarities

Evolution equations

• Deterministic equations (ordinary/partial differential equations) 
• Probabilistic equations Markov dynamics (no memory)
  • Master equation 
  • Fokker-Planck equation (diffusion) 

Differences

Conservation laws

• Physical systems - global conservation (global energy) 
• Evolutionary systems - local conservation (no single global "potential", typically a set of local "potentials")

The simplest model of a living system

metabolism

nutrients

energy

ATP

chemical reaction network

energy \(E_n\)

# particles \(N_n\)

evolution

genotype

phenotype

fitness function \(\Psi_n\)

environment

ATP synthase

...

Importance of ST in living systems

Entropy production - the arrow of time

$$\Sigma = D_{KL}(P(x(t))||\tilde{P}(\tilde{x}(t))) $$

• \(D_{KL}(p\|q) = \sum_i p_i \log \frac{p_i}{q_i}\)  is the Kullback-Leibler divergence
•  \(P(x(t))\) is the probability of forward trajectory
• \(\tilde{P}(\tilde{x}(t))\) is the probability of backward trajectory

EP is the measure of the time irreversibility of a system

Many results of non-equilibrium thermodynamics remain valid also for non-physical systems

\( \frac{P(\Sigma_t = A)}{\tilde{P}(\Sigma_t= -A)} = e^{At} \)

FT's

\(\frac{Var(J_t)}{E(J_t)^2} \geq \frac{2}{\Sigma_t}\)

TUR's

\(\frac{L(p(t),p(0))}{2 \Sigma_t \bar{A}_t} \leq t\)

SLT's

Two recent papers

Analogy between thermodynamics and evolution

Is it the correct framework?

Can we learn something from this picture?