How important was/is marine life and marine ecosystems to the theory of evolution and why?
Evolution is a topic I got interested in because of my PhD advisor. He works in both sedimentology and paleontology and uses foraminifera to understand evolution. Most of the record of ancient life is preserved in marine deposits. Terrestrial environments are not very conducive to the preservation of dead organisms. Marine environments are relatively better. Also before the Ordovician- Silurian the only record of macroscopic life is from marine deposits. That makes marine ecosystems of primary importance for studying the evolution of life. Marine depositional basins may last for tens of millions of years. Within these basins sediments are deposited as packages during sea level rise and are separated by unconformities (periods of non deposition) that develop during sea level fall. If you take large enough time slices then these packets of sediment are roughly contemporaneous over large regions of the globe. In shallow water settings we thus have a fossil record of benthic ecosystems / c
