Problem
As head of the International Space Agency's Intergalatic Evolution and Ecology Unit, you must plan a fossil-hunting mission to another planet, but due to budget limitations you have been approved for only one expedition. Your boss has shortlisted three candidate planets for exploration. Based on preliminary observations (brief descriptions listed below), on which planet would you expect to find the greatest abundance of fossils? Give at least three evidence-based arguments to justify your choice.
Note that there may be more than one acceptable answer, but you need to provide solid, evidence-based reasoning based on the information given.
Note: You can make the following assumptions when selecting your planet: 1. All planets are of similar age to Earth. 2. Decomposition and other mechanisms relevant for fossilization occur on these planets as they do on Earth. 3. Planets are all a similar distance from the sun and experience comparable seasonal temperature deviations. 4. Lacking any knowledge to the contrary, you assume that environments, species, and population abundances in the past would have been relatively similar to what is present now.
• Planet 1: This tectonically active planet is dominated by desert environments and some oceans. Volcanic eruptions and the formation of rift valleys and active subduction zones are regular occurrences. Soft algae and soft-bodied animals are found in the ocean in moderate abundances. A few leafy plants and a diversity of insect- and scorpion-like animals with hard exoskeletons dominate the land at low densities due to the desert environment.
• Planet 2: This swampy planet is characterized by a cool climate. The landscape is relatively flat with a few mountain ranges, and relatively little tectonic activity. Bushy, wooded plants surround swamps and the wildlife is dominated by large populations of several burrowing, rodent-like species (with an internal skeleton). These species are widespread and found across the planet.
• Planet 3: Most of the surface is covered in sulfuric oceans that are too inhospitable for life forms. Several mountain ranges are found across the few existing islands, with new mountain ranges forming regularly. These mountains create rain shadows, resulting in some habitats that are very dry and others that experience high rates of precipitation with fast-flowing rivers. Researchers have identified a few small, isolated populations of a caribou-like organism with large antlers and internal skeletons.