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 degrees and lie in the grooves between larger, underlying cells (spiral cleavage). If we were to separate these eight cells and attempt to culture them individually, then what is most

likely to happen?

TLS Online TPP Program

#Question id: 8896

#Unit 9. Diversity of Life Forms

Chordate pharyngeal slits appear to have functioned first as

TLS Online TPP Program

#Question id: 8897

#Unit 9. Diversity of Life Forms

Which of the following statements would be least acceptable to most zoologists?

TLS Online TPP Program

#Question id: 8898

#Unit 9. Diversity of Life Forms

Which extant chordates are postulated to be most like the earliest chordates in appearance?

TLS Online TPP Program

#Question id: 8899

#Unit 9. Diversity of Life Forms

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?

TLS Online TPP Program

#Question id: 8900

#Unit 9. Diversity of Life Forms

Which of the following statements about craniates is (are) correct?

1. Craniates are more highly cephalized than are non-craniates.

2. Craniatesʹ genomic evolution includes duplication of clusters of genes that code for transcription factors.

3. The craniate clade is synonymous with the vertebrate clade.

4. Pharyngeal slits that can assist in gas exchange originated in craniates,

5. The two-chambered heart originated with the early craniates.

TLS Online TPP Program

#Question id: 8901

#Unit 9. Diversity of Life Forms

The origin of the craniates occurred at roughly the same time as the