What do phylogenetic trees represent?

kiki · June 2021

A) anatomical similarity

the pattern of continental drift

C)the evolutionary relationships among organisms

D) the degree of similarity in the habitats occupied by different organisms

E)None of the above

Which E is not the answer so it's A-D

Please help.

rick-k · June 2021

C.

They are showing how organisms are related one to another. They are developed mainly by examining similarities in morphology and function but this has become enhanced in recent years by the used of genetic mapping. Some species originally though to be closely related are found to be actually more distant based on what we now know about rates of genetic change. Other species have been found to be more closely related by the same token even though outward appearances show them to be quite different.

Even though answer A) may seem to be correct, many organisms have very similar body structures due to evolutionary convergence. A big example here is the structure of the eyes of cephalopods (octopus and squid) and vertebrates (fish, amphibians, lizards, birds, mammals). Their eyes are VERY similar but there is no way that these two groups are closely related.

anonymous · June 2021

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I would say D. Both A and B are a similar line of reasoning, that is how many mutations have occurred in sequences derived from the same ancestral sequence over time. Depending on the gene mutation rate, and how distant the taxonomic relationships examined the strength of the resulting tree will vary. However, as with any hypothesis, being able to support it with multiple, independent lines of evidence provides the strongest support for the hypothesis. Also, with regards to "B", whether or not the gene coding for a protein has introns or not is pretty much irrelevant to the strength of an amino acid based phylogenetic tree, since only the exons (coding regions) are reflected in the AA sequence anyway.