Mollusca
Annelida
Key Properties
Arthropoda
Crustacea
100

The process undergone by a mollusc when its visceral mass rotates 180 degrees during development, resulting in looping of the digestive tract. 

What is torsion?
100

These chitinous bristles, used to create friction for locomotion, are the namesake of many segmented marine worms. 

What are chaetae?

100

A type of gas exchange system defined by blood moving in from high to low concentrations of gas, and water moving out from low to high concentrations. 

What is countercurrent exchange?

100
When fired into space (or exposed to any extreme environment), tardigrades rely on this process to survive. 

What is cryptobiosis?

100

Often used synonymously with appendage, this term more accurately describes jointed segmented legs.

What is an article?

200

This muscular part of a mollusc may be used in crawling, burrowing, cleaning, secreting, or grabbing depending on the species. 

What is the foot?

200

This tagmatized region of an annelid contains its eyes, antannae, feeding palps, and brain. 

What is the prostomium?

200

This kind of feeding is neither raptorial nor filter, and comes in two flavors: selective and nonselective. 

What is deposit feeding?

200

This kind of nervation allows for careful control of striated muscle in arthropods. 

What is polyneuronal?

200

The branching of articles, such as into exo- and endopodites. 

What is biramous?

300

A backwards-facing ribbon of chitin and protein with two rows of teeth located on top of the odontiphore. 

What is a radula?

300

The budding off of gamete-producing segments into the water column, where they are externally fertilized to produce trocophore larvae. 

What is epitoky?

300

This blood respiratory protein is found in open circulatory systems and gets part of its name from a familiar body fluid. 

What is hemolymph?

300

These two antagonistic muscles work together to bend jointed segmented articles.

What are flexor and extensor?

300

These colorful secreters are responsible for osmoregulation in crustaceans. 

What are green glands?

400
Located in the mantle cavity, these paired structures are used in gas exchange and exhale both waste and gametes. 

What are ctenidia?

400

Annelids rely on metamerism combined with a coelom to create this kind of efficient movement. 

What is a peristaltic wave?

400

This category of metazoan (introduced for the last exam) serves as a a plesiomorph for molluscs, annelids, and arthropods. 

What is a protostome?

400

These two biological macromolecules make up most of an arthropod's chitinous exoskeleton.

What are polysaccharides and protein?
400

This organ works with the cardiac and pyloric stomachs to digest a crustacean's food by grinding down prey. 

What is a gastric mill?

500
Specialized bundles of nerves analogous to a brain found in the head of molluscs.

What are ganglia?

500

The layer that secretes septa, thin tissue layers responsible for annelid segmentation. 

What is the mesoderm peritoneum?

500

The definition of "-pod", as in gastropod, cephalopod, copepod, arthropod...

What is a foot?

500

The hardening of an exoskeleton with cross-linked proteins; often occurs during the second-to-last step of ecdysis. 

What is sclerotization?

500

Crabs can be distinguished from shrimp by looking at these five key traits. 

What are body length (short vs long), abdomen position (under vs next to thorax), uropods (not present vs present), pleopod uses (reproduction only vs reproduction, movement, and respiration), and claw size (big vs small)?

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