One of the great questions that Palaeontology poses is how did life and the Earth co-evolve together? This is especially so in the case of early life during the Phanerozoic period (540 million years ago until now), when complex multi-cellular life took off and ultimately came to dominate the planet. When one considers the vast number of potential factors involved in this, it can be pretty overwhelming. To start off with, you have organisms themselves which adapt through altering their physical appearance and functionality. Driving this, you have the environment and the ecosystems in which organisms dwell. How many parameters can you think off that may have some effect, any effect, on the life of an organism or population of organisms, that could have some impact on evolutionary trajectory? There’s a lot, right? Some of the major environmental factors include oxygen and carbon dioxide concentrations, nitrogen, temperature, humidity. You can find variations of almost any environmental variable nowadays, and correspond it to variability in the local biota. But what about during the Phanerozoic? How much can we still see left preserving this great orchestra of ever-changing life and planet?
The complex spiral of life on Earth. But what about the fine points of co-evolutionary history? Source: Astrobioblog (click for larger image)
