This is the ninth post in our series The Impact of Gravity on Life, a paper written by Dr. Emily R. Morey-Holton, NASA Ames Research Center, Moffett Field, California. Read the series in its entirety here in blog posts tagged Impact of Gravity on Life.
Life most likely will look and, perhaps, move quite differently after many generations in space. We have learned that life is “plastic” and changes with the environment; it adapts at least transiently to changes in gravity. The microenvironments of spaceflight require more study so that we will understand how to use them effectively. We certainly have a lot to learn about the complexity of biological responses to altered gravity. Data to date suggest that certain biological structures have evolved to sense and oppose biomechanical loads, and those structures occur at the cellular as well as at the organismal level. Certainly, the Earth-tuned physiological systems of vertebrates change following acute exposure to space; what will happen over multiple generations is speculative. The “functional hypothesis” theory suggests “use it or lose it”. If this theory holds over multiple generations in space, then gravity-dependent structures may ultimately disappear or assume a very different appearance. Based on the studies described in this paper, gravity most likely is essential for life, as we know it.