Summary

Nick Lane explores the ten great innovations of evolution by natural selection. This includes 1) the origin of life, 2) DNA, 3) photosynthesis, 4) the complex cell, 5) sex, 6) movement, 7) sight, 8) hot blood, 9) consciousness, and 10) death. Taken together, Lane makes a strong case for humans representing the leading edge of earthly evolution. Extrapolating the most important trends, we see that effective replicator recombination, complex emergent hierarchical cooperation, as well as increasing energy use and data processing capability drive evolutionary success.

Key Takeaways

• The 10 great evolutionary inventions
• Drivers of evolutionary success:
  • Effective replicator recombination
  • Complex emergent hierarchical cooperation
  • Increasing energy use and data processing

The 10 Great Evolutionary Inventions

1. The origin of life: Primordial soup, thermodynamics, H2O forms basis of life on earth
2. DNA: Original replicator (along with RNA), error rate allows for evolution
3. Photosynthesis: Oxygen in photosynthesis + respiration drives large, high-energy life
4. The complex cell: Cambrian explosion, single progenitor cell founded all kingdoms of complex life
5. Sex: Genetic recombination, selective interference, brings together favorable combinations
6. Movement: Led to more interactions, diverse ecosystems, development of senses
7. Sight: Provides massive sensory advantage, predator + prey arms race
8. Hot blood: 30x higher metabolism / energy, more stamina + size + resiliency, bigger brains
9. Consciousness: Neural Darwinism allows for intra-life evolution, emergent cultural memetics
10. Death: Mandatory for natural selection (differential survival), multicellular life (specialization)

Notes

1: Origin of life - From out the turning globe

• Criteria:
  • Had to revolutionize the living world and thus the planet as a whole
  • Had to be of importance today
  • Had to be the direct outcome of evolution by natural selection
  • Had to be iconic in some way
• Primordial soup: primitive gasses leads to amino acids, but not gasses on earth
• Thermodynamics is basis of complexity
• H2O is basis of life on earth
• Primordial soup has no reactive molecules - where did the energy come from?
• Black smoke vents underwater provide disequilibrium needed for life (sulfur)
• Actually, serpentine vents emitting hydrogen form more likely basis for life
• All life uses cells, ATP, Krebs Cycle, implying shared evolution from evolutionary parent
• Reverse Krebs Cycle produces energy / ATP, powers other 4 cycles → basis for RNA
• Chemi-osmosis: → proton gradient - another key to all life
• First life was porous rock that used proton gradient to generate proteins, DNA etc.

2: DNA - The code of life

• 3B pairs in human genome (3 Gb)
• Error rate: 1 in 1B
• Only about 1% of genomes have changed since species start, 1.4% from apes
• DNA → RNA → 20 amino acids → proteins
• Directed panspermia: Life seeded only once by extraterrestrial means
  • Given how unlikely all DNA → protein code is same across all life
• Actually 1-in-a-million optimized
• DNA evolved once, replication evolved 2x
• Thermal vents home to RNA, start of life

3: Photosynthesis - Summoned by the sun

• Oxygen in photosynthesis + respiration drives life
• Z-scheme: in photosynthesis - input of energy, output of ATP, input of energy
• The hydrogen economy

4: The complex cell - A fateful encounter

• Cambrian explosion 540M years ago, over only 2M years where fossil records started showing
• Eukaryotes (us) and prokaryotes
• Mitochondria must co-evolve but its genetic evolution is 10,000 quicker
• Jumping genes + introns

5: Sex - the greatest lottery on earth

• “Sex is the most peculiar randomizer of genes known”
• Asexual cloning spreads through pool quickly but leads to death of species
• Genetic recombination hides rare, detrimental mutations
  • Also hides good mutations, so just better for introducing more genetic variation
• Sex is beneficial for the individual as well
• Sex exists to combat parasites and their gene editing
• Selective interference: true benefit of sex
• Sex is similar to regular cell replication so little evolution involved

6: Movement - the power and the glory

• Locomotion has led to more complex (diverse) ecosystems
• Plants and animals have coevolved to take advantage of locomotion (flowers, fruits)
• Muscles are key innovation for locomotion
• Muscle motion due to potential across electrolytes rather than electrons
• Myosin ATP usage rate determines speed
• Striated and smooth muscle very different

7: Sight - from the land of the blind

• Eyes: 95% of animal species (6 / 36 phyla)
• Chapter explains how sight could have progressively evolved from raw retina
• Humans have trichromatic vision, red likely evolved to read facial emotion
• Most species have dichromatic, some (like sharks) have 4 color vision

8: Hot blood - breaking the energy barrier

• Hot blood = ↑ metabolism = ↑ activity
• More heat allows more reactions
• Oxygen consumption 2x with 10° temp rise
  • 2x power, speed, etc.
• Bigger = more heat (surface area ratio)
• Greatest advantage: stamina
• Stamina = evolved for ↑ max metabolic rate
• Not sure why RMR, AMR are linked (10x stamina)

9: Consciousness - roots of the human mind

• Consciousness: self-awareness
• Two types of consciousness
• Consciousness is one whole
• “Emotion is the foundation of intellect”
• Feelings are an evolved physical phenomenon

10: Death - the price of immortality

• Multicellular life = mandatory specialization = only some germ cells = somatic cells are subservient to germ line = beneficial death
• Multicellular life evolved independently 5+ times throughout evolution
• Can’t select for lifespan after genes passed on (especially at detriment to early life)
• Calorie restriction leads to a longer life but we’re not sure why (SIRT-1 and TOR)
• Low free radical leak, low metabolism correlated with longer lifespan
• Neurons most valuable, specialized cells but no neuronal stem cells (no replacement)
• “The price of immortality is our humanity”