Adaptation

      The key to any organism’s success lies in its ability to adapt to its environment and the other organisms living there. Adaptation requires modification throughout the evolution of a population that allows that population to be more successful and live more cohesively among the other organisms in its ecosystem. Success refers to the ability of an organism to grow, develop, and reproduce effectively in this ecosystem, or wherever the organism may end up.

      One adaptation that Cassiopea xamachana can do is switch between reproducing asexually and sexually through the alternation of generations (Post et al. 2012). If the environment or parasites are posing a threat to the upside-down jellyfish, reproducing sexually can be a way of staying one step ahead of parasites. This is called the Red Queen hypothesis, and it refers to a mechanism that makes it more difficult for parasites to adapt and evolve in a way that makes Cassiopea xamachana vulnerable to them (Campbell et al. 2008). The other part of the alternation of generations is reproducing asexually. By using the asexual reproduction process, many more offspring are produced and at a much quicker rate, less energy is imputed into those offspring from the parents, and males are not needed; males are seen as a limiting factor in sexual reproduction.  The problem with asexual reproduction is that it makes the upside-down jellyfish vulnerable to being wiped out and completely controlled by parasites because of the lack of genetic variability (Campbell et al. 2008).

     Cassiopea xamachana have adapted to live symbiotically with other organisms. Both the upside-down jellyfish and its photosynthetic partners have adapted to live with each other so well that it is not known if the jellyfish can survive without their symbionts (Thornhill et al. 2006). One thing that plays a role in adjoining the upside-down jellyfish and its symbiotic organisms is the chemicals present in the area and the organisms. They are capable of mutualistic symbiosis with a variety of dinoflagellates. It is the environment or location of the host Cassiopea xamachana that is usually the determining factor as to which dinoflagellate it will have a mutualistic bond with. Another way that Cassiopea xamachana adapt is by being able to change symbiotic partners based on their surrounding environment (Thornhill et al. 2006). They have also adjusted to living with their photosynthetic symbiotic partner by resting their bell on the sediment. The symbiotic partner resides on the hosts arms which are directed to the sunlight. The combination of resting on its bell and letting the photosynthetic partner reside on its arms is a useful modification (Santhanakrishnan et al. 2012). By resting on its bell, there is more surface area for the symbiotic partner to be on, and it does not have to expend as much energy keeping itself afloat (Santhanakrishnan et al. 2012). Lastly, the oral arms, or tentacles, are the only safe place for the dinoflagellates. If they were located in the gastrovascular cavity, (the inside of the jellyfish) they would be digested (Campbell et al. 2008).    

      Cassiopea xamachana has also adapted to its predators. Like many other jellyfish, its mucus will cause a stinging sensation to the part of the predator that it comes in contact with. When humans come into contact with the mucus, an itchy rash will occur.  Crabs have noticed the protection that the stinging mucus gives the upside-down jellyfish. As a result, crabs have adapted to their own predators by carrying Cassiopea xamachana on their backs (Living Florida 2013).