/sci/ - Science & Math

>>6294254
Think about it. Say you have a desert animal such as a jerboa, cobra, lizard, ect... and it has gills. An organ evolved to process oxygen from water would not only be useless in this environment, but would severely decrease that animal's ability to maintain a stable and sustainable water balance. If an animal living in a dry environment had open-aired sensitive organs that must be wet at all times in order to function, it would be extremely difficult to retain water in said animal's body. Also, evolution tends to simply get rid of things that animals no longer need, turning them into vestigial organs. It's just the way things are. Also, extra unneeded organs take energy to maintain, and the majority of the energy you take in goes to maintaining your organs. Having a major organ such as a pair of gills that is useless would be an extreme disadvantage for an organism's survival.