Learning Curve CH 29: Animal Orgins and the Evolution of Body Plans

Refer to the table. (Click image to enlarge.)"V" is a shared, derived character state for deuterostomes in which character(s)?

26

Which of the following does not contribute to evidence that animals have a common ancestor?

Animals have bilateral symmetry and exhibit cleavage.

In animals with two or more life stages, which is least associated with dispersal?

Caterpillar

Which structural parts of a sponge are responsible for creating water currents and capturing food?

Choanocytes

Which is not an example of a trade-off that would constrain evolution?

Colonial species that consist of individuals that become specialized for different functions

Refer to the table. (Click image to enlarge.)The character states of characters 25 and 27 are shared and derived for which clade(s)?

Deuterostomes only

Refer to the figure. (Click image to enlarge.)Ctenophores are radially symmetrical. Which group shown in the figure shares this trait with the ctenophores?

Echinoderms

Refer to the figure. (Click image to enlarge.)Which animal has a feeding strategy similar to that of the two the organisms shown in the figure?

Flamingo

Which of the following includes only deuterostomes?

Human, lizard, echinoderm, and chicken

Which statement concerning colonial animals is false?

Individuals in a colony are genetically diverse.

Which statement about the medusa phase of cnidarians is true?

It is the gamete production and dispersal stage

Which statement about pseudocoelomate animals is true?

Mesoderm lines the body cavity but does not surround organs.

Refer to the figure. (Click image to enlarge.)Which pair of terms best describes the mobility and feeding strategy of the comb jelly (a ctenophore) shown?

Motile, predator

Ctenophores are animals with true tissues that lack most of the Hox genes found in all other members of their clade. They have a radially symmetrical body plan, are diploblastic, and have cells organized into tissues. Based on this information, which would be the most appropriate group in which to classify the ctenophores?

Sister group to all other animals

Fluid-filled internal body cavities function as hydrostatic skeletons that facilitate movement. Which animal has a body cavity that functions as a hydrostatic skeleton?

Snail

Which statement regarding some species of hydrozoans is false?

Some have no known sexual reproduction.

Refer to the figure. (Click image to enlarge.)Which best describes the segmentation shown in the part B of the figure (the scorpion)?

Specialization of body regions

Animals appear to have evolved from a common ancestor. Which statement about the early evolution of animals is false?

Studies of Hox genes suggest a polyphyletic origin for the animal kingdom.

Refer to the figure. (Click image to enlarge.)Which statement concerning the two forms shown is true?

They function in dispersal of the species.

Which statement concerning ctenophores (the comb jellies) is false?

They have a polyp stage.

Which characteristic distinguishes sponges from all other animal groups?

They have no distinct tissues or organs.

Which statement best reflects a change that would occur during an evolutionary transition from direct development to metamorphosis?

Upon hatching, some eggs produce underdeveloped young.

A body form with radial symmetry is most likely found in

a predator that drifts through the ocean.

A coral animal is a _______ cnidarian in the group known as the _______.

colonial; anthozoans

The major animal groups exhibit multiple feeding strategies because there is

competition with other animal species to obtain food.

Refer to the figure. (Click image to enlarge.)The nauplius shown is the larval form of

crustaceans only.

An insect with a life cycle in which similar food resources are used by all life stages would most likely exhibit

direct development.

Herbivory could evolve from a predatory feeding strategy through

existence of an omnivorous feeding strategy.

The characteristic of sponges that most resembles the hypothetical animal ancestor is their

flagellated choanocyte.

A member of the protostome group of animals

has a mouth derived from the blastopore.

The characteristic that best defines placozoans as animals is that they

have two surface layers with a layer of contractile fibers in between them.

There are three major groups of cnidarians: the anthozoans (which include sessile colonial corals), the scyphozoans (jellyfish), and the

hydrozoans.

Cnidarians typically have two body forms: one asexual and the other sexual. The sexual form is the _______, and it differs most from the asexual form in that it is _______.

medusa; free swimming

The body cavity of a coelomate organism would act as a hydrostatic skeleton because

muscular contraction would cause fluid movement in the cavity.

Refer to the figure. (Click image to enlarge.)The trochophore shown is the larval form of

polychaete worms and mollusks.

The _______ are marine cnidarians with a thick, firm mesoglea within the medusa.

scyphozoans

All of the following are necessary parts of a hydrostatic skeleton except

segmentation.

Filter feeders differ from predators in that filter feeders

strain food from their environment, while predators capture and subdue their prey.

A female frog can lay large numbers of eggs but these eggs have small energy stores. This demonstrates a reproductive

trade-off

Sponges

were once thought to be plants.