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Unformatted text preview: imals with diploblastic development form a
d. Animals with triploblastic development are a clade. Sponges (Porifera)
The older edition of your textbook (Life, 8th Edition) treated
sponges as a paraphyletic group comprising three clades:
1. glass sponges (Hexactinellida)
2. demosponges (Demospongiae)
3. calcareous sponges (Calcarea)
What would this suggest about the features observed in
sponges? Major lineages of
to older (8th) edition
of Life 3 Sponges (Porifera) Clicker Question 2. Pick the best answer.
Based on the phylogeny presented in the older edition of
your textbook (Life, 8th Edition), features shared among
sponges are likely to represent:
d. If sponges were a paraphyletic group, as in the phylogeny
below, the most parsimonious interpretation would be that
features observed in sponges trace back to their MRCA –
which is the MRCA of all animals! Eumetazoan synapomorphies.
Synapomorphies of the glass sponges.
Ancestral metazoan conditions.
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- Spring '09