Basics of Biology

Biology and Life

How did different forms of life evolve on Earth?

No one really knows how life evolved on Earth. One of the reasons is the minute size (single cells) of the first organisms, which makes it difficult to detect them in ancient rocks. In addition, most of the oldest rocks have been exposed to the heat and pressure of geologic activity over time, making detection impossible by erasing all traces of that life. The following is only one interpretation of how early life on Earth developed (all years are approximations):


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