Arthropods, Annelids, and Mollusks: Key Characteristics and Roles

What does the word arthropod mean?

Jointed legs

What are 3 distinct characteristics of arthropods?

Jointed legs, exoskeleton, segmented body, well-developed head, paired appendages, and very active.

How are arthropods of economic importance?

They serve as food, disease vectors, pests, pollinators, and producers of honey, silk, wax, dyes, and medicine.

What are the 3 body parts of an arthropod?

Head, thorax, and abdomen.

What is the major disadvantage of an exoskeleton?

It must be shed through molting in order for the animal to grow.

Which animals belong to the subphylum myriopods and what does the word mean?

Centipedes and millipedes; it means many-footed.

What are the differences between Chilopoda and Diplopoda?

Chilopoda (centipedes) are nocturnal predators with one pair of appendages per segment; Diplopoda (millipedes) are scavengers that feed on vegetation with two pairs of appendages per segment.

What is a cephalothorax?

A body segment formed by the fusion of the head and thorax.

How do earthworms reproduce?

They are hermaphrodites that use a clitellum to secrete mucus for sperm exchange and create a cocoon for fertilized eggs.

Do earthworms have a complete digestive system?

True

Do Pogonophorans have a complete digestive system?

False, they do not have a digestive system.

How are leeches used in medicine?

They provide natural anticoagulants, encourage blood flow to healing areas, and are used in microsurgeries and reattachments.

How is the blood of horseshoe crabs used?

It is used to clean and sterilize medical equipment.

Do all spiders build webs?

False, but all spiders produce silk.

What is a notable characteristic of tardigrades?

They are the most resilient animals in existence and capable of cryptobiosis.

What are setae?

Bristle-like structures extending from annelid segments that help them stay in place.

Are annelids segmented internally, externally, or both?

Both.

What are 4 traits that make leeches effective parasites?

Anterior and posterior suckers, heat/smell sensing for blood vessels, anticoagulant saliva, and a gut that expands up to 4 times its size.

In what area of the ocean are Pogonophorans found?

The deep sea.

What class do earthworms belong to?

Oligochaetes.

What are parapodia?

Extensions on each segment of a polychaete that assist in movement.

What are the 2 types of muscles found in annelids?

Longitudinal and circular.

What is a coelom and what is its purpose?

A fluid-filled body cavity surrounded by tissue that allows for hydrostatic movement through muscle contraction.