Exam 27: The Rise of Animal Diversity

In the traditional phylogeny (A),the phylum Platyhelminthes is depicted as a sister taxon to the rest of the protostome phyla and as having diverged earlier from the lineage that led to the rest of the protostomes.In the molecular phylogeny (B),Platyhelminthes is depicted as a lophotrochozoan phylum.What probably led to this change?

What should be true of fossils of the earliest tetrapods?

Had the teacher wanted to point out organisms that move and feed using the same structural adaptation,the teacher should have chosen the

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

During chordate evolution,what is the sequence (from earliest to most recent)in which the following structures arose? 1)amniotic egg 2)paired fins 3)jaws 4)four-chambered heart

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

Which clade does not include humans?

Please use the following information to answer the questions below. Figure 27.2 Fishes that have swim bladders can regulate their density and thus their buoyancy.There are two types of swim bladder: physostomous and physoclistous.The ancestral version is the physostomous 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 physoclistous 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

What do all craniates have that earlier chordates did not have?

Which tree(s)has (have)been created by emphasizing the structural simplicity of placozoans?

On the basis of the information in the paragraph,which of these should be able to be observed in Tp?

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

Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans?

One important evolutionary change that occurred with the rise of animals is

Which statement is most consistent with the hypothesis that the Cambrian explosion was caused by the rise of predator-prey relationships?

What is true of the feeding stage of cycliophorans? 1)It is chemoheterotrophic. 2)It is sessile. 3)Its tube feet allow it to feed efficiently. 4)It has radial symmetry.

Which of these are amniotes?

Which of the following characteristics distinguishes modern humans from other modern apes? 1)Humans walk upright. 2)Humans walk on two legs. 3)Humans use simple tools. 4)Humans are capable of symbolic thought.

Arrange these taxonomic terms from most inclusive (most general)to least inclusive (most specific). 1)lobe-fins 2)amphibians 3)gnathostomes 4)osteichthyans 5)tetrapods

Table 27.1.Proposed Number of Hox Genes in Various Extant and Extinct Animals -All things being equal,which of these is the simplest explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates,as shown in Table 27.1?