Low light and evolution

[Thallone]

Not to say that all the evolutionary biology and all that is wrong, but considering how a captive-bred coral only reproduces it's best-adapted polyps, it would seem to me that after a few generations in captivity, the corals would require far less light. After all, if that were not the case, then why are acroporas that are fouth and fifth generation preferred over ocean-harvested ones? The ocean harvested ones should be heartier and more diverse in their simbiotic zoxanthelle(sp, I know), and thus should have a better survival chance. The truth is, the generations of captive breeding cause a selection of the simbiants that are the most active under the lower lighting conditions of the tank, and thus the most able to survive in captive aquaria. This same type of captive selection should also be able, after several more generations, be able to produce sps corals that require not too much more light than the average leather or even mushroom polyp.

Well, that's my $.02. feel free to pick my theory apart.

DOH! Wrong button. This was meant to be in the Low light corals thread.

[This message has been edited by Thallone (edited 01-25-2001).]

[horge]

Hi Thallone,

Well, the rebuttal is mostly within your very statements. The coral adapts to a given lighting situation by altering density or type of hosted dinoflagellate "zooxanthellae". Adaptation is not evolution, and since the adaptation can hinge on the availability of the appropriate dinoflagellate species in the water, it can be more luck than general hardiness at work.

Corals straight from the reef are IMO healthier, but are SPOILED on ideal lighting and prey-densities. Bring them into our badly-lit, polluted, crowded, pathogen-loaded glass boxes, and... well, it's no surprise so many of them don't make it

Facing severe changes in lighting spectrum leads to expulsion of the hosted zooxanthellae in the hope of recruiting a better strain or species of the same. There's not always an availability of a better deal, zooxanthellae-wise.

Propagated frags may have simply lucked out in recruiting the right zooxanthellae to better suit the lamps that the hobby uses.


horge

[Brooke]

That is a very interesting way of thinking. And, in a way, I've seen that happen with captive raised xenia. I received a cutting of xenia that was at least 5-6th generation. It spread, we made cuttings, etc. I was able to keep it in our FO with NO (normal output) lights. Obviously growth was better under VHO, but I found it quite capable of adapting to a number of lighting conditions.

This would definately be an interesting experiment, especially on SPS.

Brooke

[MRIGUY]

Very interesting concepts. I agree that it would make an interesting experiment but keep in mind the five to ten generations is well below the sensitivity threshold for envirmental adaptability. The specimens may very well be adapting but the change is so slow that we would be unable to observe it. But then again.....

[AxelG]

I originated the most recent low light thread but... Being a former mad scientist/microbiologist/medical technologist (but now a PowerBuilder Developer)I had to respond to this thread. Is this possible? I know in the microbial world, which so little is known about, that anything is possible. We know so little about the ocean. Any thoughts? Are we doing more harm than good?