Exam 31: Animal Origins and the Evolution of Body Plans

The existence of three embryonic cell layers, including an outer _______, an inner _______, and a middle _______, is a synapomorphy for protostomes and deuterostomes.

The endosymbiotic dinoflagellates present in many corals

A pseudocolomate animal lacks a

Use the following to answer questions : Refer to the diagram below, showing the life cycle of a cnidarian. -What is indicated by label D?

A bilaterally symmetrical animal can be divided into mirror images by

Bilateral symmetry

Cnidarians have the type of symmetry known as _______ symmetry.

Use the following to answer questions : Refer to the diagram below, depicting a sponge cross-section. -Which structure is an epidermal cell?

Use the following to answer questions : Refer to the diagram below, depicting a sponge cross-section. -Which structure is a spicule?

Bilateral symmetry

Discuss two evolutionary trade-offs involving reproduction that animals are confronted with.

Placozoans, ctenophorans, and cnidarians are all considered _______, since they have inner and outer cell layers.

Which of the following is not a feature that enables some animals to capture large prey?

Some species of hydrozoans

Motile filter feeders include

An important factor contributing to the evolution of diversity among animals is the considerable variation in their

There are three major groups of cnidarians: the _______ (which include sessile colonial corals), the _______ (commonly known as jellyfish), and the _______.

Which of the following is a significant threat to the coral reefs in many parts of the world?

In the common ancestor of protostomes and deuterostomes, the pattern of early cleavage was

Of the more than 9,000 species of sponges, _______ live in fresh water.