Consider the phylogenetic tree presented in the following figu...

Question

Consider the phylogenetic tree presented in the following figure (Figure 17.17). How were the origins of secondary endosymbiosis in the brown algae determined?

Phylogenetic tree illustrating secondary endosymbiosis origins in brown algae and related organisms.

Accepted Answer

Everyone. Let's take a look at this question together. What is the most accepted theory concerning the origin of secondary endo symbiosis in brown algae? Is it answer choice. A, a heterotrophic eu cario engulfing a red algal cell. Answer choice B A heterotrophic eukaryote engulfing a green algal cell. Answer choice C the fusion of two separate eukaryotic cells or answer choice D the transfer of genetic material across algal species. Let's work this problem out together to try to figure out which of the following answer choices is the most accepted theory concerning the origin of secondary endo symbiosis in brown algae. So when it comes to brown algae, some things that we know about them is that brown algae contains a secondary placid surrounded by four membranes. And we also know that brown algae has genetic similarities to their endo symbion. And when we're talking about brown algae containing a secondary placid surrounded by four membranes, we know that this is typical of red algae. And when it comes to brown algae having genetic similarities to their endosymbiont, we know that they gain their plastys through endosymbiont with a red algal progenitor. And so brown algae contain a secondary plast surrounded by four membranes which is typical of red algae. And they also have genetic similarities to their end symbion which they gain their placid through endosy osis with a red algal progenitor. So, from various studies on brown algae, we are able to determine that the most accepted theory concerning the origin of secondary endo symbiosis in brown algae is the engulfment of a red algal cell by a heterotrophic E cario which means that answer choice. A a heterotrophic ear out engulfing a red algal cell is the correct answer because many lines of evidence support this including the existence of a secondary placid surrounded by four membranes which is typical of red algae. And from a molecular study, we found genetic similarities between brown algae and their endosymbiont supporting the theory that brown algae gain. They are placid through secondary endosymbiont with that red algal progenitor. So the most plausible scenario for the origin of secondary endosy in brown algae is the engulfment of a red algal cell by heterotrophic ear out, which means that answer choice. A a heterotrophic eu Caro engulfing a red alga cell is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

Consider the phylogenetic tree presented in the following figure (Figure 17.17). How were the origins of secondary endosymbiosis in the brown algae determined?

Key Concepts

Phylogenetic Trees

Secondary Endosymbiosis

Molecular Phylogenetics

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