Lecture 10: Complexity & Evolvability

Question 1

What is the main concept that this lecture is about? summarize!

Answer 1

• Lecture 10, “Complexity & Evolvability,” examines constraints on macroevolution and the role of complex systems in evolvability.
• Complexity has intrinsic limitations; complex systems display emergent properties beyond simple part interactions. Modularity and gene duplication likely drove the rapid phenotypic shifts in the Cambrian period, as evolvability thrives on modularity and adaptability within complex, dynamic systems.

Question 2

What are constraints on Macroevolution?

Answer 2

o Structural (limits on material properties),
o Transfer (gas/molecule transfer limits),
o Functional (optimal mechanical forms),
o Historical (ancestral constraints),
o Developmental (modularity and pleiotropy limitations),
o Complex Systems (optimized evolvability).

Question 3

Darwin’s Phylogeny

Answer 3

Emphasizes increasing complexity and diversity over time in evolutionary history

Question 4

Assembly Theory

Answer 4

Measures the evolution of molecular complexity using the Molecular Assembly Index (MA), suggesting that living organisms produce unique complex molecules not found in non-living systems.

Question 5

Evolvability

Answer 5

Defined as the capacity to generate heritable variation; increased through modularity, parcellation, and gene duplication. These elements enhance an organism’s ability to evolve new traits.

Question 6

Stable Networks

Answer 6

Evolution of stable biological networks involving genes and hormones across generations, contributing to adaptability in complex systems.

Question 7

Gene Duplication and Complexity

Answer 7

Gene duplication events, particularly during the Cambrian Explosion, allowed for rapid body plan diversification. This may mark a threshold in complexity evolution.

Question 8

Complexity Optima

Answer 8

Discusses optimized systems like language and DNA, where modular building blocks (e.g., words, amino acids) assemble into complex structures.

Question 9

Zip’s Law and Language Vs. Genetics

Answer 9

Observes how language’s frequency distribution reflects the organization in genetic and protein interactions, underscoring efficient complexity in both systems.

Question 10

Pathways to Modularity

Answer 10

Evolutionary trend from integrated to modular phenotypes, decoupling traits, allowing independent variation in structures such as arthropod appendages and mammalian skulls.