Phylogenetic groups:
<ul><li>A <a href="https://en.wikipedia.org/wiki/monophyletic" class="extiw" title="en:monophyletic">monophyletic</a> <a href="https://en.wikipedia.org/wiki/taxon" class="extiw" title="en:taxon">taxon</a> contains a common <a href="https://en.wikipedia.org/wiki/ancestor" class="extiw" title="en:ancestor">ancestor</a> and all of its descendants.
<ul><li><i>Diagram: in yellow, <span style="background-color:#fffc00; padding: 2px">the group of "reptiles and birds"</span></i></li></ul></li>
<li>A <a href="https://en.wikipedia.org/wiki/paraphyletic" class="extiw" title="en:paraphyletic">paraphyletic</a> taxon contains its <a href="https://en.wikipedia.org/wiki/most_recent_common_ancestor" class="extiw" title="en:most recent common ancestor">most recent common ancestor</a>, but does not contain <i>all</i> the descendants of that ancestor.
<ul><li><i>Diagram: in cyan, <span style="background-color:#00efff; padding: 2px">the reptiles</span></i></li></ul></li>
<li>A <a href="https://en.wikipedia.org/wiki/polyphyletic" class="extiw" title="en:polyphyletic">polyphyletic</a> taxon does not contain the most recent common ancestor of all its members.
<ul><li><i>Diagram: in red, <span style="background-color:#ff0202; padding: 2px">the group of "all warm-blooded animals"</span></i></li></ul></li></ul>
<a href="https://en.wikipedia.org/wiki/User:TotoBaggins" class="extiw" title="wikipedia:User:TotoBaggins">TotoBaggins</a> at <a href="https://en.wikipedia.org/wiki/" class="extiw" title="wikipedia:">English Wikipedia</a>
12 January 2007 (original upload date)
Transferred from <span class="plainlinks"><a class="external text" href="https://en.wikipedia.org">en.wikipedia</a></span> to Commons.