According to an answer key, there should be a comma before "called". However, I thought it was part of the subject and in a subject, there should not be commas. Can anyone explain why there is a comma?

These single-celled survivors, called extremophiles, don't merely endure environments too serve for other life forms.


closed as off-topic by Davo, David, NVZ, Scott, Hellion Oct 9 '17 at 18:03

This question appears to be off-topic. The users who voted to close gave this specific reason:

If this question can be reworded to fit the rules in the help center, please edit the question.

  • There is a comma because you are not distinguishing the single-celled survivors in question from others by giving their name. See: en.wikipedia.org/wiki/… – Khuldraeseth na'Barya Jul 19 '17 at 21:04
  • So would this require commas: I have a lot of friends and one of them, Alex, is a tennis player. – G.B Jul 19 '17 at 21:09
  • And basically, if it is a proper noun, it will most likely go between commas, correct? – G.B Jul 19 '17 at 21:11
  • 3
    The phrase called extremophiles is reduced from the nonrestrictive relative clause which are called extremophiles. Since it's nonrestrictive, it has to be separated by comma intonation at both ends. The relative clause modifies survivors, so it is part of the subject, but it's not the word called that modifies it -- it's the whole reduced clause. – John Lawler Jul 19 '17 at 22:30
  • @G.B No, proper nouns can go either way: That man, Johannathan, runs vs My friend Johannathan runs. – Khuldraeseth na'Barya Jul 19 '17 at 23:55

These single-celled survivors, called extremophiles, don't merely endure environments too serve for other life forms.

-called extremophiles is closed in by commas because the commas act as an appositive

Appositives are words that add information to a noun or noun phrase that precede them. They are always enclosed by commas.

In your example the added information = what the single celled survivors are called.

Here are a few more examples.

  1. Liverpool**, my home town,** is a wonderful place.

  2. My friend**, called Fred,** is not very clever.

  3. English**, my favourite subject,** is very challenging.

Appositives function to add more information and to make our language more interesting.

I hope that helps you.

Source: Advanced Grammar Course Manual. BC Ministry of Education, Canada.


There is a comma because it is used as parenthesis. You are separating a subordinate clause - a part of the sentence that doesn't make sense on its own. This is why you have two commas in the sentence. If you remove the section within the commas, the rest of the sentence still makes sense.


I agree commas are warranted before and after called extremophiles but must call attention to typo: "too serve" I believe should be "too severe."

Not the answer you're looking for? Browse other questions tagged or ask your own question.