Biology (Raven), 10th Edition

Chapter 23: Systematics, Phylogenies, and Comparative Biology


In a phylogeny two species more closely related to each other than to any others:
A)are always extremely similar to each other.
B)share a common ancestor.
C)must have diverged within the last million years.
D)are distantly related to all other species in the phylogeny.
E)all of the above
Phylogenetic analysis has been applied to the evolution of the human immunodeficiency virus (HIV). It has been estimated that the HIV crossed over to humans from monkeys before 1940. This is based on:
B)the assumption of the operation of a molecular clock.
C)analysis of blood samples from the 1930's.
D)medical records.
Why is overall similarity between two taxa (e.g. species) not a good indication of the degree of evolutionary relationships and time of divergence from a common ancestor?
A)Because convergent evolution can occur.
B)Because evolutionary reversal of traits can occur.
C)Selection pressures may oscillate over time.
D)Characters involved may or may not be phylogenetically meaningful.
E)All of the above.
In cladistics, which types of characters are considered to accurately reflect the evolutionary relationship between taxa?
A)Shared ancestral characters.
B)All characters.
C)Shared derived characters.
D)All ancestral characters.
E)All derived characters.
A monophyletic group:
A)includes all taxa in the lineage.
B)includes the most recent common ancestor of the group but not all its descendants.
C)does not include the most recent common ancestor of the group.
D)includes the most recent common ancestor of the group and all its descendants.
E)includes all the taxa that are the most similar.
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