Evolutionary Implications: Species 2 and 3 have many similarities in their physiologies. They both have proboscis-like organs that are used for feeding, the same mating process and reproductive organs, similar matriarchal behavior, and similar outer shells for protection. However, there are still some differences in genetic code and morphology. Additionally, the similar traits are most likely not the product of convergent evolution due to enough similarities in genetic code. Because of this, species 2 and 3 can be classified into the same class. Due to drastic biological differences between species 1 and species 2 and 3, species 1 is most likely only in the same kingdom as species 2 and 3. This also implies that species 2 and 3 share a more recent common ancestor than species 1 and 2 or 3 share.
Another interesting observation to note is how slow (relative to species on Earth) the organisms are on Kepler-442 b. This is most likely the product of Kepler-442 b’s higher gravity: organisms need to expend more energy the faster they move. On Kepler-442 b, the energy required to move fast in an environment with a relatively high gravitational acceleration is not available. Consequently, organisms evolved to move at a slower pace. Additionally, the heightened gravity has led organisms to evolve into flatter, more muscular, and denser forms. For example, the head of an adult female of species 2 has high muscle density in order to keep it above ground. Organisms on this planet do not get much taller than 10 meters.
Species 1, 2, and 3 have also evolved to survive through Kepler-442 b’s long rotational periods. Species 1 always moves with the planet's rotation in order to constantly be photosynthesizing. Species 1 and 2 also move with the planet's rotation: species 2 follows species 1 in order to have food readily available, which causes species 3 to follow species 2 for the same reason. Both species 1 and 2 have evolved to sleep while moving in order to keep up with the planet's rotation. If any of these species are caught on the nightside of the planet, they will typically not survive. Other organisms adapted for the night side of the planet can prey on them, as well as limited resources.
Ecological Implications: Species 3 is likely a keystone species due to its control over the populations of species 1 and 2. Species 3 controls the population of species 2 by preying on it, which in turn controls the population of species 1. If species 3 were removed from this system, the population of species 1 would grow rapidly, causing a large disruption in the population of species 1, which could be detrimental to the ecosystem as a whole.
It’s also important to note that the 10% rule of trophic levels also still applies in this ecosystem: the overall biomass of species 1, 2, and 3 decreases as energy is moved up trophic levels.