Exam 32: An Introduction to Animal Diversity

Which of the following genetic processes may be most helpful in accounting for the Cambrian explosion?

Which of the following characteristics is shared among animals ranging from corals to monkeys?

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise one hemisphere of the embryo seem to be rotated 45° and to lie in the grooves between larger, underlying cells. Which of the following organisms is this embryo most likely to develop into?

Evidence of which structure or characteristic would be rare to find among fossils of the Ediacaran fauna?

Which of the following statements concerning animal taxonomy is accurate?

Based on the tree, which statement is true?

Which of the following is an advantage of using molecular data rather than morphological data for phylogenetic analysis?

In examining an unknown animal species during its embryonic development, how can you be sure what you are looking at exhibits protostome or deuterostome development?

Which of the following characteristics represents the oldest branch point in animal phylogeny?

At one time, sponges were lumped into one phylum. Then, they were separated into several different phyla. Now, they are considered one phylum again. These changes indicate which of the following?

Which of the following processes contributed the most to the successful evolution o of the millions of animal species?

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise one hemisphere of the embryo seem to be rotated 45° and to lie in the grooves between larger, underlying cells. If we were to separate these eight cells and attempt to culture them individually, then what is most likely to happen?

Which of the following inferences can best be made from the fact that arthropods colonized land about 100 million years before vertebrates?

Both animals and fungi are heterotrophic. Which of the following distinguishes animal heterotrophy from fungal heterotrophy?

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups-Lophotrochozoa and Ecdysozoa. What does this finding suggest?

Placing sponges as the basal metazoans on the basis of lack of tissues implies which of the following?

The larvae of some insects are merely small versions of the adult, whereas the larvae of other insects look completely different from adults, eat different foods, and may live in different habitats. Which of the following is most directly involved in the evolution of these variations in metamorphosis?

The last common ancestor of all bilaterians is thought to have had four Hox genes. Most extant cnidarians have two Hox genes, though some have three Hox genes. On the basis of these observations, some scientists have proposed that the ancestral cnidarian's were originally bilateral and, in stages, lost Hox genes from their genomes. If true, what would this mean regarding the phylogeny of animals?