Chapter 32: Animal Diversity (BIOL1510)

Which characteristic below is shared by plants, fungi, and animals?

They are multicellular eukaryotes.

Which of the following is NOT a characteristic of all animals? -They are all multicellular. -They ingest their food. -They have tissues, organs, and organ systems. -They are heterotrophic. -They are eukaryotes.

They have tissues, organs, and organ systems. Sponges are considered animals, and they lack these levels of organization.

All animals with bilateral symmetry have __________ germ layer(s).

Three All bilaterally symmetrical animals have three germ layers.

The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of ______.

True tissues

Which of the following correctly lists the embryonic stages in the order that they develop?

Zygote, blastula, gastrula, larva A zygote is the first embryonic stage, and the final stage is the larva.

In a phylogenetic tree, a lineage that diverges from all other members of its group early in the evolutionary history of the group is described as ____.

A basal taxon

Which of the following is a trait shared by protostomes and deuterostomes?

A body cavity Protostomes and deuterostomes have a body cavity, although the way that it forms is different.

A true coelom is __________.

A body cavity lined with mesoderm A true coelom is a fluid-filled body cavity lined with tissue derived from mesoderm.

Which of the following is radially symmetrical? -A dog -A doughnut -A submarine sandwich -A spoon -An automobile

A doughnut A doughnut has no front, no back, no left, and no right.

During the development of most animals, cleavage leads to __________.

A multicellular blastula The blastula is a multicellular stage, which in many animals takes the form of a hollow ball.

Depending on the blastopore fate of its members, label each branch with P (for protostomy), D (for deuterostomy), N (for neither), or P & D. Labels may be used once, more than once or not at all.

Acoela: Neither Echinodermata: Deuterostomy Chordata: Deuterostomy Platyhelminthes: Protostomy Rotifera: Protostomy Mollusca: Protostomy & Deuterostomy Annelida: Protostomy & Deuterostomy Nematoda: Protostomy Arthropoda: Protostomy & Deuterostomy

Based on the tree in Figure 32.11, which statement is false?

Acoelomate flatworms are more closely related to echinoderms than to annelids.

Animals probably evolved from colonial protists. How do animals differ from these protist ancestors?

Animals have more cells than their protist ancestors, and their cells show greater specialization.

Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). -A pseudocoelom has the same functions as a true coelom. -In a pseudocoelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the muscles. -An acoelomate triploblast has no endoderm. -A diploblast has no mesoderm. -In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the lining of the digestive tract. -The digestive tract of a coelomate functions as a coelom. -In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.

-A pseudocoelom has the same functions as a true coelom. -A diploblast has no mesoderm. -In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity.

Which type of symmetry does each of the following animals display?

Asymmetry: Sponge Radial symmetry: Jelly and Hydra Bilateral symmetry: Bobcat, Snake, Octopus, and Turtle Animal bodies may exhibit symmetry or a lack of symmetry (asymmetry). Some symmetrical animals exhibit radial symmetry, in which the body is wheel- or spoke-shaped, with no obvious front, back, right, or left. Other symmetrical animals exhibit bilateral symmetry, in which the body has left and right sides, a front and back, and a top and bottom.

Which of the following is characteristic of protostomes?

Cell fate is determined early during embryonic development. This is known as determinate development and is characteristic of protostomes.

Which of the following is a characteristic of cnidarians?

Ectoderm and endoderm Cnidarians are diploblastic.

Which example below is a current hypothesis regarding the Cambrian explosion?

Evolution of the Hox gene complex provided developmental flexibility.

Which of the following occurred during the Mesozoic era?

Flight evolved in pterosaurs and birds. This was the era in which flight first evolved in vertebrates.

Among the characteristics unique to animals is ______.

Gastrulation

Which of the following is the most inclusive term for an organism that obtains organic food material by eating other organisms or substances derived from them?

Heterotroph

The presence of a coelom is advantageous because __________.

It allows room for the development and movement of internal organs A body cavity enables the internal organs to grow and move independently of the outer body wall.

For the common ancestor of all the Bilateria, what was the fate of the blastopore? -Protostomy (P) -Deuterostomy (D) -Neither (N) -It is impossible to tell from the data provided.

It is impossible to tell from the data provided. Based on the phylogeny, the ancestral condition in bilaterians may have been similar to that in Acoela, where the blastopore closes and the mouth forms elsewhere (N); however, it is also possible that blastopore fate in Acoela is a derived trait and hence is not informative about the ancestral condition.

Which of the following groups does NOT exhibit bilateral symmetry?

Jellies Individuals in the phylum Cnidaria represent an early branch of the animal kingdom. The other groups mentioned in this question exhibit bilateral symmetry, but jellies exhibit radial symmetry.

Unlike other animals, sponges __________.

Lack true tissues

Many young animals are __________, a sexually immature form that is morphologically distinct from the adult stage. These young animals undergo __________ to become __________, which resemble adults but are not yet sexually mature.

Larvae ... metamorphosis ... juveniles Larvae go through metamorphosis to become juveniles.

One of the primary developmental/anatomical characteristics distinguishing the major animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in which the body cavity is __________.

Lined on one side by mesoderm and on the other side by endoderm If the cavity is not completely lined by tissue derived from mesoderm, it is termed a pseudocoelom.

How many times has blastopore fate changed over the course of evolution? -0 times -1 time -2 times -Multiple times, though the exact number is uncertain.

Multiple times, though the exact number is uncertain. The phylogeny indicates that blastopore fate has changed multiple times over the course of evolution. However, a precise determination cannot be made. For example, if we assume that the ancestral condition was similar to that in Acoela and that the common ancestor of all non-Acoela bilaterians (marked with a 1 on the tree) exhibited protostomy, then blastopore fate has changed at least five times: once in common ancestor 1, once in Deuterostomia, at least once in Mollusca, at least once in Annelida, and at least once in Arthropoda. Other assumptions would lead to different estimates.

Gastrulation is the process that directly forms the _____. -Organs -Muscles -Primary germ layers -Central nervous system -Blastula

Primary germ layers Gastrulation gives rise to either two or three germ layers.

Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither.

Protostome: spiral, determinate cleavage, coelom from solid masses of mesoderm, and mouth from blastopore. Deuterostome: radial, indeterminate cleavage, coelom from folds of archenteron, and anus from blastopore. Both: Tripoblast Neither: Diploblast

An animal with a true coelom that has __________ cleavage must be a(n) __________.

Radial ... deuterostome A true coelom is a fluid-filled body cavity lined with mesoderm. Deuterostomes are characterized by radial cleavage.

Indeterminate cleavage produces embryonic cells that __________.

Retain the capacity to develop into a complete embryo Each cell produced by the first few mitotic divisions can develop into a complete embryo.

The zygotes of many protostomes undergo __________ cleavage and __________ cleavage.

Spiral ... determinate

Which of the following is the defining characteristic of the clade Ecdysozoa for which this group is named?

The secretion of stiff external skeletons that must be shed to permit growth Though named for this characteristic, the clade is actually defined mainly by molecular evidence supporting common ancestry.

A mutualism is an ecological relationship between two species ____.

That both benefit from the relationship.

In the embryo of a shark, ectoderm gives rise to __________; mesoderm gives rise to __________; endoderm gives rise to __________.

The central nervous system ... muscle ... the lining of the digestive tube Each of these is associated with the germ layer that gives rise to it.

Which of the following was probably the least important factor in bringing about the Cambrian explosion?

The movement of animals onto land.