Arthropoda II

What are the four main classes under Subphylum Crustacea that are the focus of study?

Class Ostracoda, Class Branchiopoda, Class Thecostraca, Class Malacostraca.

How are crustaceans distinguished from other arthropods?

They possess 2 pairs of antennae, a pair of mandibles, two pairs of maxillae, and appendages on all other body segments.

What is the typical body segment arrangement of most crustaceans?

Most have 16-20 segments, with a head of 5 fused segments, thorax of 8 segments, and abdomen of 6 segments.

What are the major tagma in crustaceans?

Head, thorax, and abdomen.

What type of circulatory system do crustaceans have?

They have an open circulatory system with no separation between blood and interstitial fluid.

How do small crustaceans breathe?

They rely on diffusion across thin areas of the cuticle.

What are paired ostia in crustaceans?

They are openings in the heart that help circulate blood within the open circulatory system.

In the context of crustaceans, what are maxillipeds used for?

Maxillipeds are appendages that hold and crush food.

What is the larval stage in the crustacean life cycle?

The larval stage is called the nauplius.

What class of crustaceans is known for being bioluminescent and having a flattened, leaf-like leg morphology?

Class Branchiopoda.

How do Class Thecostraca crustaceans feed?

They use their long thoracic legs to capture food.

What is a key characteristic of the Class Malacostraca?

They are diverse in morphology and include economically important species like crabs, lobsters, and shrimp.

What is significant about the Order Euphausiacea in the crustacean class?

They are known as 'Krill' and are important in aquatic food webs, serving as critical food for baleen whales and fishes.

What is a notable educational importance of Class Ostracoda?

They are important in aquatic food webs and have 6,000 extant species contributing to their ecological role.

What reproductive strategy do most crustaceans employ?

Most are dioecious and brood their eggs, with indirect development being the norm.

What adaptation do some crustacean larvae have in times of harsh conditions?

They can produce fertilized eggs that withstand harsh conditions.