Oxygenic photosynthesis has been a key factor for the development of multicellular macro-organisms such as plants and animals on Earth. Oxygenic photosynthesis uses photons in the 400 nm to 700 nm spectral region, known as "photosynthetically active radiation" (PAR). To see if plants and animals could evolve on TRAPPIST-1 e (a known planet in the habitable zone), we employ an Earth-analog model where we replace TRAPPIST-1 e with a hypothetical Earth. The critical difference is that the star TRAPPIST-1 is much smaller and lower temperature than the Sun. Compared to the Earth, this planet only receives 0.91% of photons within the PAR. On Earth it took roughly 700 million years to build up significant amounts of oxygen in the atmosphere, whereas on TRAPPIST-1e it would take approximately 77 billion years. Considering this over 5 times the age the universe, we conclude that the likelihood of plants and animals being present on TRAPPIST-1 e is very low.
