Definitions [7]
Biogenesis is the idea that life arises only from pre-existing life.
Abiogenesis is the concept that living organisms can arise naturally from non-living substances.
Autogenesis is another term for spontaneous generation, meaning self-origin of life from non-living matter.
The process where organisms with favorable variations survive and reproduce more successfully than others is called natural selection.
The concept where only well-adapted individuals survive in the struggle for existence is called survival of the fittest.
The process where organisms with favorable variations survive and reproduce more successfully than others is called natural selection.
The concept where only well-adapted individuals survive in the struggle for existence is called survival of the fittest.
Key Points
- The origin of life is a unique event; Earth formed about 4.5 billion years ago, and life appeared about 4 billion years ago.
- Special Creation Theory: all organisms were created by a supernatural power; religion-based, no scientific proof.
- Cosmozoic Theory (Panspermia): life came from other planets as spores; not accepted, as it doesn't explain life's origin elsewhere.
- Spontaneous Generation (Abiogenesis): life arose from non-living matter; later disproved.
- Biogenesis: life arises only from pre-existing life; explains continuity but not the first origin.
- Redi (1668): maggots appeared only in the uncovered meat jar, showing they came from fly eggs.
- Spallanzani (1767): sealed boiled broth showed no growth, proving microbes come from air.
- Pasteur (1861): swan-neck flask trapped airborne microbes, conclusively disproving spontaneous generation.
