You discover a new species of ape that is more closely related to gorillas than to any other species of ape, but walks upright. How would you change the phylogeny below? Photo sources: (left to right) Zoonar/K. Jorgensen/age fotostock; S Sailer/A Sailer/age fotostock; J & C Sohns/age fotostock; Michael Dick/ Animals Animals-Earth Scenes; FLPA/Jurgen & Christi/age fotostock; Yellow Dog Productions/Getty Images.
A)I would not change the phylogeny at all because only molecular data are considered when studying evolutionary relationships.
B)I would not change the phylogeny at all until a fossil of the new species is found because fossil evidence is a required component of the data set.
C)I would group gorillas with humans based on the synapomorphy (shared trait)of upright stance.
D)I would branch the gorilla lineage and add the new species sister to gorillas.

Question

You discover a new species of ape that is more closely related to gorillas than to any other species of ape, but walks upright. How would you change the phylogeny below?  Photo sources: (left to right) Zoonar/K. Jorgensen/age fotostock; S Sailer/A Sailer/age fotostock; J & C Sohns/age fotostock; Michael Dick/ Animals Animals-Earth Scenes; FLPA/Jurgen & Christi/age fotostock; Yellow Dog Productions/Getty Images.
A)I would not change the phylogeny at all because only molecular data are considered when studying evolutionary relationships. 
B)I would not change the phylogeny at all until a fossil of the new species is found because fossil evidence is a required component of the data set. 
C)I would group gorillas with humans based on the synapomorphy (shared trait)of upright stance. 
D)I would branch the gorilla lineage and add the new species sister to gorillas.

Quizplus · Accepted Answer

Since the new species is more closely related to gorillas than to any other species of ape, it should be added as a sister species to the gorilla lineage. Even though it walks upright, this trait alone does not warrant grouping gorillas with humans, as they have many other differences. Additionally, while fossil evidence can provide important information about evolutionary relationships, it is not the only source of data considered when constructing a phylogeny.

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