The first idea, the process of evolution drives the diversity and unity of life, is presented by the evolution of HeLa cells. Cells must adapt to their ecological niche. This happens when a cell divides, genetic mutations occur, and those that make the cells better suited to their ecological niche, or their Petri dish, are preserved by natural selection. “When Henrietta Lacks' cells became cancerous, they also acquired the ability to survive indefinitely in a culture medium; that massive genetic transformation made them fundamentally different from normal human cells, and after four decades of evolution they have become even more different. Different strains of HeLa cells, analogous to different races of humans, have even developed into some geographically separate lineages.” (discovermagazine.com). The second idea, that biological systems use free energy and molecular building blocks to grow, reproduce, and maintain dynamic homeostasis, is represented when cells reproduce. HeLa cells are considered immortal, meaning they are kept alive and can grow indefinitely. This tells us that cells are not in homeostasis because their “births” exceed their “deaths”. The reason for this and the type of energy the cells use are not fully known, making it difficult to fully connect HeLa cells to AP Biology's second big idea. THE