Why are protists considered paraphyletic?
a. They include many extinct forms, including lineages that no longer have any living representatives.
b. They include some but not all descendants of their most recent common ancestor.
c. They represent all of the descendants of a single common ancestor.
d. Not all protists have all of the synapomorphies that define the Eukarya, such as a nucleus.

Question

Why are protists considered paraphyletic?

a. They include many extinct forms, including lineages that no longer have any living representatives.

b. They include some but not all descendants of their most recent common ancestor.

c. They represent all of the descendants of a single common ancestor.

d. Not all protists have all of the synapomorphies that define the Eukarya, such as a nucleus.

Accepted Answer

Hi everyone here's our next question. It says proteas are considered blank as they include some but not all descendants of their most recent common ancestor. So let's look through our answer choices, noting that choice D. Is both A. And B. So we want to be alert to that possibility. So Choice A. Says mono, fill a tick while a mon affiliated group. As we can note by the prefix mono meaning one is a group that consists of a common ancestor and all of its lineal descendants. So if you're looking at a philo genetic tree, you can just chop off um anaphylactic um branch because it includes a common ancestor and then everything descended from it. So that's not what we have here because we see that protease includes some but not all. So choice A is not correct. That also means that choice D. Cannot be our answer since A. Is not correct. So let's look at choice B. That says para Philip dick. And that is indeed the term that we're looking for. Para filet tick means a group that includes a common ancestor and some but not all of its descendants. In the case of proteas, uh that group does not include the multicellular organisms that are descendants of the common ancestor. So para syphilitic is the term we're looking for. Let's look at the last one. We haven't looked at choice C. Polypill epic and polypill attic means a grouping without a common ancestor. Whereas with protease they do have a common ancestor. The group just doesn't include all of the descendants of that ancestor. Choice C. Is not our answer, and so we have proteins are considered choice be paralytic as they include some, but not all descendants of their most recent common ancestor. See you in the next video.

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Key Concepts

Paraphyletic Group

Protists

Synapomorphies