Molecular Machinery
Molecular Machines as Functional Systems
Living cells contain organized molecular assemblies that perform functions resembling motors, transport systems, assembly lines, information processors, and quality-control machinery.
System Integration
Integrated Cellular Organization
Molecular machines operate as parts of larger cellular systems in which energy, information, transport, quality control, regulation, and repair depend upon one another.
Evolutionary Explanation
Evolution by Modification and Co-option
Evolutionary biology proposes that complex molecular systems can arise by modifying existing components, duplicating genes, recruiting parts used elsewhere, and preserving useful intermediate functions.
Irreducible Complexity
Irreducible Complexity and the Design Argument
The argument from irreducible complexity claims that some systems require several interacting parts before their present function can operate, raising questions about how they could arise through successive selectable stages.
Comparative Assessment
Can Molecular Machines Be Built Step by Step?
The central issue is whether known evolutionary mechanisms provide an adequate account of the origin of complex molecular machinery or whether some systems provide positive evidence of intelligent organization.
