Biyogenezis

Biyogenezis, also known as biogenesis, is the principle that life arises only from pre-existing life. In biology it underpins the understanding that organisms reproduce and pass genetic information to their offspring. The concept stands in contrast to abiogenesis, the idea that life can arise from non-living matter, a topic that remains central to origin-of-life research.

Historically, many ancient thinkers believed in spontaneous generation, the notion that living things could arise from decaying matter or fluids. Experiments by Francesco Redi in the 17th century showed that maggots originate from eggs laid by flies, not from meat itself, challenging spontaneous generation for larger organisms. In the 18th century, Lazzaro Spallanzani boiled nutrient broth and sealed flasks, finding no microbial growth; later critics argued about air exposure. A decisive breakthrough came with Louis Pasteur in 1859, whose sterilized broth in swan-neck flasks remained free of microorganisms while exposed to air, demonstrating that microbes originate from existing organisms rather than from the broth or air alone.

Today biogenesis is supported by the modern cell theory, which holds that all living things are composed of cells and arise by cell division and reproduction. The overarching rule in biology is that life arises from pre-existing life. In parallel, origin-of-life research continues to investigate abiogenesis, asking how the first self-replicating entities and metabolic networks could have formed from chemistry on early Earth. In contemporary practice, biogenesis also informs fields such as microbiology, embryology, and ecology, emphasizing the continuity of life across generations.