How does gravity affect evolution of life?

I have two "new" planet earths -- we'll call them Light Earth (LE) and Heavy Earth (HE). These planets are generally the same as our Earth in terms of land masses, oceans, the moon and sun and other terrestrial objects, weather, and so forth. The difference between them and our Earth is in the force of gravity. On LE, gravity is less than that of our Earth, and on HE, gravity is greater than ours.

How does gravity affect the evolution of flora and fauna? Would trees be taller on LE and bushes more prevalent on HE? Would there be no birds on HE? (And if there are no flying birds, are there more dinosaur-like things still present? or more emu-like birds?) Would there be more fish at greater depths in LE?

This question is only about the evolution of life on the HE and LE planets. I am aware that a difference gravity would change how the planet itself would evolve (plate tectonics, atmosphere, etc etc). We're going to ignore that for now.

^{I'm looking for the general overall effects of a different gravity on evolution -- something like "there will be fewer flying mammals in higher gravity, and they will compensate by XYZ." I've intentionally not given numerical values for "higher" and "lower" gravity, but let's consider a range of [10%,190%] of our Earth's gravity, if such a thing matters.}

^{Please note that I'm intentionally not changing the gravity of our Earth. These are brand new almost-duplicate Earths (minus the gravity) whose wildlife and plant life evolved in that environment. The majority of the gravity related questions here appear to be about taking an existing organism from our Earth and placing it in a new gravity environment; this question is intentionally not about that.}

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posted about 8 years ago

Roddy of the Frozen Peas‭

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