Explain cladistics as a method of classifying organisms.

a. cladistics uses cladograms/tree diagrams;
b. show clades/branches (in parallel) that begin at a point/node;
c. each clade includes a (common) ancestral organism/node and all its descendents;
d. members of a clade share derived/inherited characteristics;
e. clades are nested/subsets of larger clades;
f. cladograms show evolutionary history/origin of organisms / phylogeny;
g. branch length (of clade) can indicate (relative) amount of genetic change/time;
h. clades based on (objective) molecular analysis/genetic evidence / differ in amino acid sequences/DNA base changes/mutations;
i. fewest number of differences/maximum parsimony determines branch separation;
j. predictability of DNA base changes/mutation rates suggests evolutionary timelines;
k. problems arise when gene change varies (greatly) from one gene to the next;
l. cladograms may not match traditional/Linnaean classification;
m. (mismatch) prompts re-examination of data / reclassification of a group;
Some of the above points may be included in a correctly annotated diagram clearly stating above points.

This was probably the most poorly answered of the longer response questions on this paper.  Candidates did not seem to have enough knowledge about cladistics to allow them to respond adequately and marks above 2 or 3 were rarely seen.  As they were unable to communicate ideas on clades clearly they waffled and were repetitive.  Better candidates were able to discuss cladograms to some degree.  Better teaching of this topic is required.