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Life Doesn't Change Terrain Much - Universe Today
Even through life has flourished on Earth for billions of years, it doesn't seem to make much of an impact on our planet's landscapes. A team of scientists from UC Berkeley did an extensive survey of landscapes across the planet, and couldn't find any place that was obviously modified by lifeforms; from large grazing animals to microscopic bacteria. The only effect seems to be that lifeforms will tend to round off sharp hills. So landscapes once covered with life on Mars might have a higher chance of being smoother and less jagged.