Exam 27: The Rise of Animal Diversity

Figure 27.2 Fishes that have swim bladders can regulate their density and thus their buoyancy. There are two types of swim bladder: physostomus and physoclistus. The ancestral version is the physostomus version, in which the swim bladder is connected to the esophagus via a short tube (Figure 27.2). The fish fills this version by swimming to the surface, taking gulps of air, and directing them into the swim bladder. Air is removed from this version by "belching." The physoclistus version is more derived, and has lost its connection to the esophagus. Instead, gas enters and leaves the swim bladder via special circulatory mechanisms within the wall of the swim bladder. -The presence of a swim bladder allows the typical ray-finned fish to stop swimming and still

Among the invertebrate phyla, phylum Arthropoda is unique in possessing members that have

In coelacanths, a swim bladder is present, but the swim bladder is full of adipose tissue (fat), which is there on a fairly permanent basis. If such a swim bladder is used by coelacanths to affect buoyancy, then it does so in much the same way as does the

Which of the following are the only extant animals that descended directly from dinosaurs?

Regarding its position in the water column, the same thing that happens to a shark when it stops swimming also happens to a

Which of these characteristics added most to vertebrate success in relatively dry environments?

Table 27.1. Proposed Number of Hox Genes in Various Extant and Extinct Animals -What conclusion is apparent from the data in Table 27.1?

Placozoan evolutionary relationships to other animals are currently unclear, and different phylogenies can be created, depending on the character used to infer relatedness. Sponges have no tissues, but about 20 cell types. Tp (Trichoplax adhaerens) produces a neuropeptide almost identical to one found in cnidarians. The genome of Tp, although the smallest of any known animal, shares many features of complex eumetazoan (even human!) genomes. The next three questions refer to the phylogenetic trees that follow. I. II. III. -Which phylogeny has been created by emphasizing a protein found in placozoans?

When a shark stops swimming, it does which of the following? 1. sinks 2) quickly dies 3) oxygenates its blood less effectively

Which of the following characterize at least some members of the phylum Cnidaria? 1. a gastrovascular cavity 2) a polyp stage 3) a medusa stage 4) cnidocytes 5) a pseudocoelom

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

A new, sixth global mass-extinction event appears to be occurring on Earth today. The most likely explanation for the dramatic loss of species is

What should be true of fossils of the earliest tetrapods?

Which of the following clades contains the greatest number of animal species?

To which of the following are the scales of chondrichthyans most closely related in a structural sense?

Corals are most closely related to which group?

Tp's body symmetry seems to be most like that of

According to the evidence collected so far, the animal kingdom is

The swim bladder of ray-finned fishes

What is the probable sequence in which the following clades of animals originated, from earliest to most recent? 1. tetrapods 2) vertebrates 3) deuterostomes 4) amniotes 5) bilaterians