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Sep 19, 2022 · When did life on Earth begin? Earth is about 4.5 billion years old. Scientists think that by 4.3 billion years ago, Earth may have developed conditions suitable to support life. The oldest known fossils, however, are only 3.7 billion years old.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day.
Mar 8, 2024 · Here are 3 popular theories. The first signs of microbial life emerged around 3.5 billion years ago. Scientists think early life may have formed from lighting strikes or arisen in deep...
- Simple organic molecules were formed. Simple organic molecules, similar to the nucleotide shown below, are the building blocks of life and must have been involved in its origin.
- Replicating molecules evolved and began to undergo natural selection. All living things reproduce, copying their genetic material and passing it on to their offspring.
- Replicating molecules became enclosed within a cell membrane. The evolution of a membrane surrounding the genetic material provided two huge advantages: the products of the genetic material could be kept close by and the internal environment of this proto-cell could be different than the external environment.
- Some cells began to evolve modern metabolic processes and out-competed those with older forms of metabolism. Up until this point, life had probably relied on RNA for most jobs (as described in Step 2 above).
Scientists disagree about which chemical components of life came first, which of life’s processes came first, and where on Earth life first arose.
Oct 25, 2024 · The origin of life is a result of a supernatural event—that is, one irretrievably beyond the descriptive powers of physics, chemistry, and other science. Life, particularly simple forms, spontaneously and readily arises from nonliving matter in short periods of time, today as in the past.
Oct 25, 2024 · Life ultimately is a material process that arose from a nonliving material system spontaneously—and at least once in the remote past. How life originated is discussed below. Yet no evidence for spontaneous generation now can be cited.
