Chapter 27

Which of the following statements is false? a. Eumetazoans have specialized tissues and parazoans don't. b. Lophotrochozoa and Ecdysozoa are both Bilataria. c. Acoela and Cnidaria both possess radial symmetry. d. Arthropods are more closely related to nematodes than they are to annelids.

Which of the following statements about diploblasts and triploblasts is false? a. Animals that display radial symmetry are diploblasts. b. Animals that display bilateral symmetry are triploblasts. c. The endoderm gives rise to the lining of the digestive tract and the respiratory tract. d. The mesoderm gives rise to the central nervous system.

Which of the following is not a feature common to most animals? a. development into a fixed body plan b. asexual reproduction c. specialized tissues d. heterotrophic nutrient sourcing

5\. During embryonic development, unique cell layers develop into specific groups of tissues or organs during a stage called ________. a. the blastula stage b. the germ layer stage c. the gastrula stage d. the organogenesis stage

During embryonic development, unique cell layers develop into specific groups of tissues or organs during a stage called ___________. a. the blastula stage b. the germ layer stage c. the gastrula stage d. the organogenesis stage

Which of the following phenotypes would most likely be the result of a Hox gene mutation? a. abnormal body length or height b. two different eye colors c. the contraction of a genetic illness d. two fewer appendages than normal

Which of the following organisms is most likely to be a diploblast? a. sea star b. shrimp c. jellyfish d. insect

Which of the following is not possible? a. radially symmetrical diploblast b. diploblastic eucoelomate c. protostomic coelomate d. bilaterally symmetrical deuterostome

An animal whose development is marked by radial cleavage and enterocoely is __________. a. a deuterostome b. an annelid or mollusk c. either an acoelomate or eucoelomate d. none of the above

Consulting the modern phylogenetic tree of animals, which of the following would not constitute a clade? a. deuterostomes b. Iophotrochozoans c. Parazoa d. Bilateria

Which of the following is thought to be the most closely related to the common animal ancestor? a. fungal cells b. protist cells c. plant cells d. bacterial cells

As with the emergence of the Acoelomorpha phylum, it is common for ________ data to misplace animals in close relation to other species, whereas ________ data often reveals a different and more accurate evolutionary relationship. a. molecular: morphological b. molecular: fossil record c. fossil record : morphological d. morphological : molecular

Which of the following periods is the earliest during which animals may have appeared? a. Ordovician period b. Cambrian period c. Ediacaran period d. Cryogenian period

What type of data is primarily used to determine the existence and appearance of early animal species? a. molecular data b. fossil data c. morphological data d. embryological development data

The time between \(542-488\) million years ago marks which period? a. Cambrian period b. Silurian period c. Ediacaran period d. Devonian period

Until recent discoveries suggested otherwise, animals existing before the Cambrian period were believed to be: a. small and ocean-dwelling b. small and nonmotile c. small and soft-bodied d. small and radially symmetrical or asymmetrical

Plant life first appeared on land during which of the following periods? a. Cambrian period b. Ordovician period c. Silurian period d. Devonian period

Approximately how many mass extinction events occurred throughout the evolutionary history of animals? a. 3 b. 4 c. 5 d. more than 5

Why might the evolution of specialized tissues be important for animal function and complexity?

Describe and give examples of how humans display all of the features common to the animal kingdom.

How have Hox genes contributed to the diversity of animal bodv plans?

Explain some of the advantages brought about through the evolution of bilateral symmetry and coelom formation.

Describe at least two major changes to the animal phylogenetic tree that have come about due to molecular or genetic findings.

How is it that morphological data alone might lead scientists to group animals into erroneous evolutionary relationships?

Briefly describe at least two theories that attempt to explain the cause of the Cambrian explosion.

How is it that most, if not all, of the extant animal phyla today evolved during the Cambrian period if so many massive extinction events have taken place since then?