Exam 18: The Evolution of Invertebrate Diversity

You find a wormlike, soft-bodied adult animal in a mudflat. It is bilaterally symmetrical, is segmented, has a true coelom, and has a complete digestive tract. Based on these characteristics, what phylum does the animal represent?

While wading in the ocean, you look down into the water and notice an umbrella-shaped, translucent animal. It swims by pulsing its body, and long tentacles trail behind it. One of them brushes your leg. Ouch! You feel a burning sensation where it touched you. To what phylum does this creature probably belong?

Cassiopeia is a marine organism with a medusa body that has an unusual orientation: It floats upside-down. It also has a distinct coloration that is due to algae that live between the epidermis (outer)layer and gastrodermis (inner layer that lines the digestive cavity)of the Cassiopeia. The algae provide food for the Cassiopeia, and the Cassiopeia's orientation provides sunlight to the algae for photosynthesis. Cassiopeia is a/an ________, and the Cassiopeia and the algae have a ________ relationship.

In protostomes,

Which of the following statements regarding cnidarians is true?

Which of the following is a unique feature of echinoderms?

The flexible, longitudinal rod that is located between the digestive tract and the nerve cord in chordates is called the

Complete the analogy: A cuticle is to a nematode as a/an ________ is to a/an ________.

The traits that are unique to insects and have probably contributed to their diversity and success include

Which of the following statements is true of a typical animal?

________ are soil-dwellers; ________ are mostly marine; and ________ mostly inhabit fresh water.

Suppose that the bottom of an ocean floor is disrupted, and bits of algae along with other bottom-dwelling microorganisms are scattered about into the ocean water. Which organism would be able to take the best advantage of this temporary food source?

Which of the following groups includes both spiders and horseshoe crabs?

Which of the following items demonstrates radial symmetry?

Which of the following statements is true?

Flatworms (Platyhelminthes)are ________ and typically have ________.

The digestive tract of a nematode is most like which of the following?

Which part of this figure shows the thorax segment of the lobster?

Which of the following are not included among the bilateria, a clade of animals with bilateral symmetry at some stage of development?

According to recent genetic research, the complexity of an organism