Evolutionary tinkering

Evolutionary tinkering is an explanation of how evolution happens in nature. It explains that evolution works as a tinkerer who experiments with miscellaneous items, unsure of the outcome, and utilizes whatever is available to craft functional objects whose utility may only become evident later. None of the materials serve a defined purpose initially, and each can be employed in multiple ways. According to the tinkering concept, "evolution does not produce novelties from scratch". It comes from previously unseen associations of old materials to modify an existing system to give a new function or combine systems together to enhance the functions. The transformation from unicellular to multicellular during evolution is such an event which has elaborated the existing function.

The process of evolutionary tinkering takes quite a long time. As a meticulous tinkerer who continuously refines its creations, making adjustments, trimming and extending here and there, seizing every chance to gradually tailor them to their evolving purposes, this process happens over countless eons.

Most of the time, traits in nature are barely favorable enough for organisms to survive. For instance, RuBisCO is profoundly inefficient, despite the fact that it catalyzes one of the most important reactions on the planet: carbon fixation. This is likely due to the enzyme originating in the common ancestor of all plastids when the atmospheric conditions were drastically different than they are today.

In his seminal article 'Evolution and Tinkering', François Jacob first introduced the idea of tinkering to a broad audience of scientists, drawing from diverse fields such as molecular biology, evolutionary biology, and cultural anthropology. The concept of tinkering, or more precisely, the notion of bricolage, serves as a theoretical framework for analyzing various phenomena characterized by a common underlying process: the opportunistic rearrangement and recombination of existing elements. Jacob and Monod also won the Nobel Prize in 1965 for his work on the lac operon.

Natural selection is frequently likened to the work of an engineer, yet this analogy falls short. Unlike the engineer who operates based on meticulous planning and a clear vision of the end product, evolution lacks such deliberate intent. Additionally, while the engineer has access to carefully selected materials and specialized equipment tailored for their tasks, evolution relies on the resources available in its surroundings.

Moreover, the engineer's creations tend to approach a level of perfection achievable with current technology, whereas evolution does not strive for perfection but rather resembles a tinkerer. This tinkerer, akin to evolution, lacks a precise blueprint of the outcome and instead utilizes whatever materials are at hand to fashion something functional. While the engineer depends on specific materials and tools precisely suited to their project, the tinkerer makes do with miscellaneous scraps and remnants. The resulting creations of the tinkerer emerge from a series of opportunistic events, enriching their repertoire with each encounter.

The development of lungs in terrestrial vertebrates illustrates a process akin to tinkering rather than deliberate engineering. It originated in certain freshwater fish faced with oxygen deficient environments, leading them to ingest air and absorb oxygen through their esophageal walls. Over time, this behavior favored the enlargement of the esophageal surface area, eventually giving rise to lung-like structures through the emergence and enlargement of esophageal diverticula.

The brain is the key adaptive feature of humans, yet still holds mysteries regarding its precise purpose. The brain has also evolved through natural selection over millions of years, like other body parts, primarily to serve our reproductive needs. However, the human brain's development was more complex unlike straightforward evolutionary changes such as a leg into a wing. It involved adding new structures, particularly the neocortex, onto older ones. This rapid evolution led to a division between the neocortex, responsible for intellectual functions, and the older structures, controlling emotional and visceral activities. These older structures lack the discriminative and symbolic abilities of the neocortex and are primarily associated with emotions. Despite the dominance of the neocortex in intellectual processes, the older structures maintain strong connections with automatic centers, ensuring vital functions like obtaining food and responding to threats. This evolutionary process, characterized by the emergence of a dominant neocortex alongside the persistence of older systems, resembles a tinkering process, where new elements are added onto existing ones without fully replacing them.