To save: right-click (Windows) or control-click (Mac) on the image and select "Save image."

Parsimony (3 of 5) Amniotic egg clade and phylogeny Image caption: We focus in on the group of lineages that share the derived form of the egg character, an amniotic egg (A), and hypothesize that they form a clade (B.) << Back to search results

Image credit:
If you use this image in your own non-commercial project please credit it to the University of California Museum of Paleontology's Understanding Evolution (http://evolution.berkeley.edu).

This image is part of a series:

Parsimony (1 of 5) Vertebrate character matrix Character data for some major vertebrate lineages. Characters were limited to characters that are likely homologous (note that many vertebrate lineages and many characters were excluded from this example for the sake of simplicity).

Parsimony (2 of 5) Vertebrate ancestor characters From studying fossils and lineages closely related to the vertebrate clade, we hypothesize that the ancestor of vertebrates had none of these features.

Parsimony (4 of 5) All clades and phylogeny If we go through the whole table like this, grouping clades according to shared derived characters (C) we get the following hypothesis (D).

Parsimony (5 of 5) Comparison of two hypotheses The parsimony principle tells us to choose the simplest scientific explanation that fits the evidence. Hypothesis 1 requires six evolutionary changes and Hypothesis 2 requires seven evolutionary changes, with a bony skeleton evolving independently, twice. Although both fit the available data, the parsimony principle says that Hypothesis 1 is better — since it does not hypothesize unnecessarily complicated changes.