Question

The Phylogeny homework introduced you to the idea of "Sister groups." Based on this phylogeny, which two species are sister species, and what common ancestor do they share?

Answer 1

In identifying sister species using a phylogenetic tree, you should look at the most recent divergence point from which only those two species emerge. Species 1 and 2 would be considered sister species because they share an immediate common ancestor that is not shared with Species 3.

Step-by-step explanation:

The question seeks to identify which two hypothetical species are sister species based on a provided phylogenetic tree, and what common ancestor they share. Sister species are those that are each other's closest relatives and share an immediate common ancestor. To determine sister species on a phylogenetic tree, one should look for the point where their evolutionary paths diverge from a single node, representing the most recent common ancestor. When two species, such as Species 1 and Species 2, are more closely related to each other than either is to a third species, such as Species 3, they are considered sister species.

Sister groups are important for understanding evolutionary relationships, helping scientists to pose scientific questions, make inferences about evolutionary history, and improve the existing phylogenetic classifications. It is also essential to be aware that phylogenetic trees and cladograms are hypotheses that can change with new data. The process of classifying organisms and deciphering their evolutionary past is an ongoing effort that requires the comparison of morphological and genetic data.