user16651: Situation
The Community ♦ user "pokes" old questions that do not have accepted answers. This occurs so that questions come to the front of the queue on the sites landing page so that it will receive additional attention. Though it only is supposed to do this for unanswered questions, I see it happening quite often on questions, such as this one, Extending a small fragment of DNA, that have answers, but they have not been accepted.
It is often the case that these questions have a perfectly valid and upvoted answer, but it appears that the question is orphaned. Either the OP was a drive-by poster, they are no longer an active user, or they, for whatever reason have decided not to accept the answer.
Edit: As ff524 challenged that this only happens when there are "no upvoted answers", this example Do species which have a closer common ancestor to humans tend to be more intelligent? was "poked" by Community ♦ user at approximately 15:00 UTC on January 1, 2016. The question has one answer which has +7 votes. So there are cases, at least on Biology S.E. where Community ♦ user is in fact "poking" questions with upvoted answers than have no accepted answer. I have seen others over the past few months, but this is the only example on the main page today (1/1/16 at approximately 21:30 UTC).
Feature Request
This feature does not currently exist, but I have been thinking about whether there is the possibility of adding a queue for "Orphaned Questions," whereby a question that fits the above description gets added to the queue after three to six months, so that those users with the most experience in the relevant tags can vote to accept an answer. 
This queue would provide for the opportunity to give recognition to a quality answer and also keep the question from appearing as a result of Community ♦ user poke, where it inevitably just pushes new questions down or off of the landing page.
I could see the formula for addition to the Orphaned Question queue as follows:

Question has aged to a certain point (e.g. 3 or 6 months after initial posting)
The question has at least one upvoted answer


There could be a minimum threshold, greater than 3, 5, etc. upvotes

The question has been poked by the Community user to the Landing Page at least one or more times and no action has been taken by an Established user since the last time it was reposted
The OP has not been active on the SE for a specified period of time


This could be since the last Community ♦ user poke of the question


From there, the question would go to a queue so that established users in the most relevant tag could vote to accept an answer to the question.
For this I could see:

The top ten users (or some percentage for tags with low activity) of the most active tag a question is tagged under would have the question added to a review queue that they could access


Example of most active tag: A question is tagged with biochemistry which has 769 questions and proteins which has 357; the question would go to the queue of the top ten users of the biochemistry for an accepted answer vote

These reviewers would vote to accept the answer
If an answer received 5 accept votes (or a majority), then the question would be marked as accepted


There should be a minimum threshold, such as with close / reopen votes

If the answer is from one of the top ten users, then that question will be excluded from their queue, and an alternate user would be added to vote
The user that posted the question could either receive the accepted answer bonus or a bonus of some reduced point value

This would clear questions from the Community ♦ user "pokes" so that only those questions that should get another look are edited and it gives the opportunity to reward users who provided well researched answers to receive recognition for their effort.

user19650: 
From there, the question would go to a queue so that established users in the most relevant tag could vote to accept an answer to the question

No, I don't think this is a good idea. There is a reason the accepted answer and the upvoting system are separate. It's up to the OP to accept an answer, if they don't, that's fine.
This has been discussed many times at the main Meta site, the canonical question to any kind of demand for an accepting process that doesn't involve the OP is this: Would it be possible to have a "community accepted" feature? (vast list of questions closed as duplicate of that one) That feature has been declined, so it's unlikely it would be implemented just because Biology thinks it should be anyway. 
Also, the Community user really does not poke questions that have an upvoted answer:
Who is the Community user?

Randomly poke old unanswered questions* every hour so they get some attention
Questions with at least 30 days of no activity, at least one answer scoring zero, and no answers scoring above that. 

The Community user does, however, show up as having edited a question when an answer is deleted as spam, for example. I don't have 10K privileges on Biology, but I can see that happening on Health.SE, where I can see deleted answers. I am pretty sure something like that happened in your example, since it was also protected by a moderator shortly afterwards. 

16651: <h2>Situation</h2>

<p>The <a href="https://biology.stackexchange.com/users/-1/community">Community ♦ user</a> "pokes" old questions that do not have accepted answers. This occurs so that questions come to the front of the queue on the sites landing page so that it will receive additional attention. Though it only is supposed to do this for unanswered questions, I see it happening quite often on questions, such as this one, <a href="https://biology.stackexchange.com/questions/37360/extending-a-small-fragment-of-dna">Extending a small fragment of DNA</a>, that have answers, but they have not been accepted.</p>

<p>It is often the case that these questions have a perfectly valid and upvoted answer, but it appears that the question is orphaned. Either the OP was a drive-by poster, they are no longer an active user, or they, for whatever reason have decided not to accept the answer.</p>

<p><strong>Edit</strong>: As ff524 challenged that this only happens when there are "no upvoted answers", this example <a href="https://biology.stackexchange.com/questions/19547/do-species-which-have-a-closer-common-ancestor-to-humans-tend-to-be-more-intelli">Do species which have a closer common ancestor to humans tend to be more intelligent?</a> was "poked" by Community ♦ user at approximately 15:00 UTC on January 1, 2016. The question has one answer which has +7 votes. <strong>So there are cases, at least on <a href="http://biology.stackexchange.com">Biology S.E.</a> where Community ♦ user is in fact "poking" questions with upvoted answers than have no accepted answer.</strong> I have seen others over the past few months, but this is the only example on the main page today (1/1/16 at approximately 21:30 UTC).</p>

<h2>Feature Request</h2>

<p>This feature does not currently exist, but I have been thinking about whether there is the possibility of adding a queue for "Orphaned Questions," whereby a question that fits the above description gets added to the queue after three to six months, so that those users with the most experience in the relevant tags can vote to accept an answer. </p>

<p>This queue would provide for the opportunity to give recognition to a quality answer and also keep the question from appearing as a result of Community ♦ user poke, where it inevitably just pushes new questions down or off of the landing page.</p>

<p>I could see the formula for addition to the Orphaned Question queue as follows:</p>

<ul>
<li>Question has aged to a certain point (e.g. 3 or 6 months after initial posting)</li>
<li>The question has at least one upvoted answer

<ul>
<li>There could be a minimum threshold, greater than 3, 5, etc. upvotes</li>
</ul></li>
<li>The question has been poked by the Community user to the Landing Page at least one or more times and no action has been taken by an <strong>Established user</strong> since the last time it was reposted</li>
<li>The OP has not been active on the SE for a specified period of time

<ul>
<li>This could be since the last Community ♦ user poke of the question</li>
</ul></li>
</ul>

<p>From there, the question would go to a queue so that established users in the most relevant tag could vote to accept an answer to the question.</p>

<p>For this I could see:</p>

<ul>
<li>The top ten users (or some percentage for tags with low activity) of the most active tag a question is tagged under would have the question added to a review queue that they could access

<ul>
<li>Example of most active tag: A question is tagged with <a href="https://biology.stackexchange.com/questions/tagged/biochemistry" class="post-tag" title="show questions tagged &#39;biochemistry&#39;" rel="tag">biochemistry</a> which has 769 questions and <a href="https://biology.stackexchange.com/questions/tagged/proteins" class="post-tag" title="show questions tagged &#39;proteins&#39;" rel="tag">proteins</a> which has 357; the question would go to the queue of the top ten users of the <a href="https://biology.stackexchange.com/questions/tagged/biochemistry" class="post-tag" title="show questions tagged &#39;biochemistry&#39;" rel="tag">biochemistry</a> for an accepted answer vote</li>
</ul></li>
<li>These reviewers would vote to accept the answer</li>
<li>If an answer received 5 accept votes (or a majority), then the question would be marked as accepted

<ul>
<li>There should be a minimum threshold, such as with close / reopen votes</li>
</ul></li>
<li>If the answer is from one of the top ten users, then that question will be excluded from their queue, and an alternate user would be added to vote</li>
<li>The user that posted the question could either receive the accepted answer bonus or a bonus of some reduced point value</li>
</ul>

<p>This would clear questions from the Community ♦ user "pokes" so that only those questions that should get another look are edited and it gives the opportunity to reward users who provided well researched answers to receive recognition for their effort.</p>
 19650: <blockquote>
  <p>From there, the question would go to a queue so that established users in the most relevant tag could vote to accept an answer to the question</p>
</blockquote>

<p>No, I don't think this is a good idea. There is a reason the accepted answer and the upvoting system are separate. It's up to the OP to accept an answer, if they don't, that's fine.</p>

<p>This has been discussed many times at the main Meta site, the canonical question to any kind of demand for an accepting process that doesn't involve the OP is this: <a href="https://meta.stackexchange.com/questions/3669/would-it-be-possible-to-have-a-community-accepted-feature">Would it be possible to have a &quot;community accepted&quot; feature?</a> (<a href="https://meta.stackexchange.com/questions/linked/3669?lq=1">vast list of questions closed as duplicate of that one</a>) That feature has been declined, so it's unlikely it would be implemented just because Biology thinks it should be anyway. </p>

<p>Also, the Community user really does not poke questions that have an upvoted answer:</p>

<p><a href="https://meta.stackexchange.com/questions/19738/who-is-the-community-user">Who is the Community user?</a></p>

<blockquote>
  <p>Randomly poke old unanswered questions* every hour so they get some attention</p>
  
  <p>Questions with at least 30 days of no activity, at least one answer scoring zero, and no answers scoring above that. </p>
</blockquote>

<p>The Community user does, however, show up as having edited a question when an answer is deleted as spam, for example. I don't have 10K privileges on Biology, but I can see that happening on Health.SE, where I can see deleted answers. I am pretty sure something like that happened in your example, since it was also protected by a moderator shortly afterwards. </p>
