Question

You want to conduct a series of experiments involving the Hawaiian bobtail squid, so you acquired a number of eggs to incubate them under controlled laboratory conditions. However two days after the juveniles hatched from the eggs. you find that none of them is producing bioluminescence. Why? Symbiont transmission is horizontal and the Juveniles were probably colonied by a different bacterial species that cannot produce bloluminescence Symblont transmission is horizontal and involves specific selection of the symbiont from the environment. Since there are no Allvibrio fischer cells in the tanks where the Juveniles hatched, they are growing without endosymbionts. Symbiont transmission is vertical from parent to offspring. Since you obtained the esses without the parents, the juveniles have no source of endosymbionts. Since symbiont transmission is vertical from parent to offspring during es formation, the and didn't provide the juveniles with the endosymbiont. as you purchased were deffective

Answer 1

The Hawaiian bobtail squid and the bacteria Aliivibrio fischeri share a symbiotic relationship. The squid provides A.fischeri with a sugar and amino acid solution that satisfies the nutritional needs of the bacteria. The bacteria, being bioluminescent, protects the squid from predation by illuminating it with a wavelength of light similar to the one hitting it from above such that the squid's silhouette is hidden from the predator.

A.fischeri is not vertically transmittedi.e. they are not passed on from parent to offspring. Rather, the transmission is horizontal. The newly hatched squids are not associated with A.fischeri. They later acquire A.fischeri by a careful selection process during which A.fischeri is specifically selected from the wide variety of microorganisms present in the marine environment that the juvenile squids inhabit.

Hence, the reason for the absence of bioluminescence in the juveniles in this particular experiment would be because the laboratory conditions would have lacked A.fischeri, therefore making it impossible for the juveniles to acquire these bacteria.

So, the correct answer is: Symbiont transmission is horizontal and involves specific selection of the symbiont from the environment. Since there are no Aliivibrio fischeri cells in the tanks where the juveniles hatched, they are growing without endosymbionts.