Use Figure 32

Multiple Choice

Use Figure 32.3 and the following information when answering the next question.
In a review paper published in 2000, Adoutte et al. examined some animal phylogenies generated by comparing the ribosomal RNA (rRNA) of animals from many different phyla. They then integrated these independently created phylogenies into one phylogeny that best fit all the data.
Figure 32.4 compares a traditional phylogeny based on morphological characteristics (A) to the new molecular-based phylogeny described by Adoutte et al. (B) .
Note that platyhelminthes, nemerteans, and entoprocts, which do not have coeloms and are classified as acoelomates in the morphological phylogeny, are reclassified as lophotrochozoans in the molecular phylogeny. Similarly, groups classified as pseudocoelomates in the morphological phylogeny are reclassified as either lophotrochozoans or ecdysozoans in the molecular phylogeny; other lophotrochozoans and ecdysozoans have coeloms. Copyright 2000 National Academy of Sciences, U.S.A. (A. Adoutte, G. Balavoine, N. Lartillot, O. Lespinet, B. Prud'homme, and R. de Rosa. 2000. The new animal phylogeny. Proceedings of the National Academy of Science USA 97(9) :4453-56.)

Figure 32.3
-What does this reclassification based on molecular data imply about the evolution of acoelomates,pseudocoelomates,and coelomates?

A) Pseudocoelomates can be seen as an intermediate stage between acoelomate and coelomate development.
B) Although acoelomates and pseudocoelomates evolved only once,coelomates evolved multiple times in different lineages.
C) Only the animals that evolved earliest are acoelomates.
D) Some pseudocoelomates and acoelomates have evolved from coelomates.