Definitions [3]
Definition: Biogenesis
Biogenesis is the idea that life arises only from pre-existing life.
Definition: Abiogenesis
Abiogenesis is the concept that living organisms can arise naturally from non-living substances.
Definition: Autogenesis
Autogenesis is another term for spontaneous generation, meaning the self-origin of life from non-living matter.
Key Points
Key Points: The Universe
- The universe is an ever-expanding expanse encompassing all matter, energy, time, and celestial bodies.
- It is primarily structured by billions of galaxies, which are massive, gravitationally bound collections of stars and planetary systems.
- Our solar system is located within the Milky Way, which forms part of the Local Group of galaxies alongside its closest major neighbour, the Andromeda galaxy.
- Scientific consensus suggests the universe originated from a massive explosion known as the Big Bang approximately 13.7 to 15 billion years ago.
- Earth was formed around 4.5 billion years ago from a collapsing gaseous cloud, with the first life emerging roughly 500 million years later.
Key Points: Origin of Life on Earth
- 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, with 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 disproven.
- Biogenesis: life arises only from pre-existing life; it 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 the air.
- Pasteur (1861): The swan-neck flask trapped airborne microbes, conclusively disproving spontaneous generation.
