Exam 32: An Overview of Animal Diversity

Which of the following is (are)unique to animals?

Which of the following statements concerning animal taxonomy is accurate?

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

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes are absolutely conserved, which of the following would be the best choice on which to base the phylogeny?

The common ancestor of the protostomes had a coelom. What does this suggest?

You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is acoelomate?

Which of the following would you classify as something other than an animal?

The primary difference between a coelom and a pseudocoelom is ________.

Use the information to answer the question. Trichoplax adhaerens is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 µm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed, nor have embryos past the 64-cell (blastula)stage. Which of the following T. adhaerens traits is different from all other known animals?

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise 1 hemisphere of the embryo seem to be rotated 45° and to lie in the grooves between larger, underlying cells. This embryo may potentially develop into a(n)________.

When a scientist describes the "body plan" of a phylum, he or she is implying that ________.

One hypothesis suggests that the Cambrian explosion was caused by the rise of predator-prey relationships. This hypothesis is best supported by an increased incidence of which of the following fossil traces?

Soon after the coelom begins to form, a researcher injects a dye into the coelom of a deuterostome embryo. Initially, the dye should be able to flow directly into the ________.

In individual insects of some species, whole chromosomes that carry larval genes are eliminated from the genomes of somatic cells at the time of metamorphosis. A consequence of this occurrence is that ________.

Nine-banded armadillos give birth to four offspring at a time. An amazing fact about these offspring is that they are genetically identical to each other. This fact suggests ________.

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that most animals derive their nutrition by ________.

Use the information to answer the question. One small animal phylum (Placozoa)contains only two species, Trichoplax adhaerens (T. adhaerens)and T. reptans. T. adhaerens is the only species seen in over a century. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2,000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. Individual animals move using cilia, and any "edge" can lead. T. adhaerens feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. T. adhaerens sperm cells have never been observed. Embryos up to, but not past, the 64-cell (blastula)stage have been observed. On the basis of information in the paragraph, which of these should be able to be observed in T. adhaerens?

Use the table to answer the question. Proposed Number of Hox Genes in Various Extant and Extinct Animals Last Common Ancestor ofBilateria Last Common Ancestor of Insects and Vertebrates Ancestral Vertebrates Mammals 4 7 14 38-40 What conclusion can best be drawn from the data in the table?

If in the future the current molecular evidence regarding animal origins is further substantiated, which of the following statements would be correct with reference to fossil evidence that contradicts molecular evidence?

An organism that exhibits a head with sensory equipment and a brain probably also ________.