Some types of organisms originated through endosymbiosis, the engulfing of one organism by another so that a part of ...

Sangwook on December 23, 2014

Help

Please explain this question. I'm totally lost. Thanks,

2 Replies

Melody on December 23, 2014

We are told that endosymbiosis is "the engulfing of one organism by another so that a part of the former becomes a functioning part of the latter."

We know that an unusual nucleomorph has been discovered within a plant known as a chlorarachniophyte. Two types of a specific gene have been found in the DNA of this nucleomorph, and the argument explains that "one would expect to find only a single version of this gene if the nucleomorph were not the remains of an engulfed organism's nucleus."

So, we diagram the last sentence:

P: not NREON ==> SVG
not SVG ==> NREON

We know that we have two types of a specific gene, i.e. "not SVG,"--not only a single version of this gene.

So, we know that the nucleomorph is the remains of an engulfed organism's nucleus, i.e. is a byproduct of endosymbiosis, which is answer choice (E): "Chlorarachniophytes emerged as the result of two organisms having undergone endosymbiosis."

Hope that clears things up! Please let us know if you have any other questions.

Sangwook on December 23, 2014

Thanks a lot!!!