In this chapter, we delve into the unique context of favelasFavelas, Brazil's version of slumsSlums, as a case studyCase studies to explore the concepts of exaptationExaptation, self-organisationSelf-organisation, and unsupervised learning – a specific form of artificial intelligence—in impoverished architectureImpoverished architecture and urban fabricUrbanfabrics. We blend biological, philosophical, and architectural perspectives to illuminate key urban milestones: the global shift towards urbanisation and the 2020 tipping point where anthropogenic mass surpassed living mass. This underscores the urgent need to rethink material flows within our socioeconomic system. We highlight the overwhelming prevalence of buildings and infrastructure as the dominant human-made mass category, illuminating the urban footprintUrbanfootprint and architectural foundation. Our chapter is structured into five parts: critically examining exaptation from biological and architectural standpoints, presenting a case study exhibited at the Venice Biennale 2023, and proposing a material-based approach to exaptation. We prioritise primary sources, particularly in biology, to ensure accuracy and avoid deterministic or moralistic interpretations, especially when integrating current information technologies.