NextPrevious

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):



Close

This is a web preview of the "The Handy Biology Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App