It is not easy to understand how natural selection works …
Shining Sun – is there any cheaper source of energy ?
Despite the great advantages, loss of photosynthesis has occurred in diverse lineages of organisms (e.g. apicomplexans, chlorophytes, cryptophytes, diatoms, dinoflagellates, euglenophytes, and Orobanchaceae species), along with heterotrophic free-living algae, holoparasitic plants, and pathogenic protists
https://www.nature.com/articles/s41598-017-18378-8