Invertebrates and Plant Forms and Life Cycles

Biology

Invertebrates:

Echinodermata Phyla:

What other phyla relies on "hydraulics" as part of their locomotion system?

Arthropoda

Phylum Cnidaria:

How do medusa of Aurelia and Gonionemus differ in size, arrangement of tentacles, and shape of manubrium?

Aurelia has tentacles that are evenly spaced around their center; they also have a single attached to a single tentacle bud. They are more circular in shape.

The Gonionemus is narrow and has many tentacles. They are also small and are bell shaped.

What structures within the coral polyp do the radial ridges within each depression support?

Calyx and stomach

How does fragmentation contribute to the evolutionary success of anthrozoans in their environment?

For many corals, the damage that is caused to the initial coral structure by storms or strong wave actions may create fragments. These fragments move through the water and create new colonies of coral.

Durgesia

Planarians have a head. In biological terms, what constitutes a "head"?

A head in biology is the portion of a creature which has the brain, or chief ganglia of the nervous system. It may also have the mouth and/or chief sensory organs.

Class Cestoda

5a. How does a scolex compare in size to a proglottid near the scolex? Near the posterior end?

The scolex is the front end and has the suckers or hooks. It is then connected to the neck and then the proglottid. The segments can be 10-15 m long.

e. Is having a scolex significant to a fundamental process for tapeworms? For which process, and how is it significant?

The scolex is used to attach itself to the intestinal wall of the host creature. This works for the digestive process and allows the tapeworm to feed.

f. Tapeworms are specialized. Would you expect specialists to have a unique morphology? Why?

The tapeworm has components to its morphology: proglottids, scolex, and tegument. Each would have a unique function. The morphology of the tapeworm allows it to feed off its host.

Phylum Nematoda

6a. How does the number of body cavities of nematodes compare with that of flatworms?

Flatworms have no body cavities. Nematodes have one.

b. What are the advantages of a digestive tract having a separate entrance and exit?

This allows specialization zones within the digestive tract.

c. Female Ascaris are more numerous than males. Why might this be adaptive?

There might be more females so that the creature could reproduce at higher rates.

7. How would you describe the motion of a nematode?

The motion of nematodes is caused by contraction and relaxing of muscles. It can move forward by extension but not much sideways.

8a. The cuticle of Ascaris is flaky and tough. What might be an adaptive advantage of a thick and tough cuticle?

The thick, tough cuticle would protect the creature from predators more easily than a thin one.