If life on Earth is constantly evolving, why do we still have life forms such as amoebas? © Getty Images

If life on Earth is constantly evolving, why do we still have life forms such as amoebas?

Who says amoebas are less evolved?

Asked by: Tom Hampton, Townsville, Australia

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Evolution is not a ladder, with every organism steadily climbing its way to the top. It’s a cacophony of random mutations where natural selection favours the ones that are slightly better adapted to their local environment. Amoebas are simpler organisms than humans or pine trees, but they aren’t less evolved: they’re the result of the same four billion years of evolution as every other living thing. Amoebas continue to exist because they’re very well adapted to life in each of the many different ecological niches they’ve colonised, from the bottom of the sea to the inside of your skull.

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