Arthropods Staring the Crayfish Part 1 – Introduction & External Anatomy

There are Four Main Groups of Arthropods ______________(crayfish, lobsters, shrimp) ________ & ___________ ______________ (spiders) __________ (bugs, beetles, butterflies, grasshoppers, etc.)

Crayfish – External Anatomy Crayfish are _______________ Have an _______________ (2 parts) –Cephalothorax –Abdomen The part that covers the cephalothorax is called the _________________

__________________________

Each segment of both the cephalothorax and the abdomen contain a pair of appendages. The cephalothorax is divided into 13 segments The abdomen is divided into 6 segments The head region also has 5 pairs of appendages.

The long ___________ are organs for touch, taste, and smell.

The ______________ are organs of balance, touch, and taste.

The ____________, or jaws, crush food by moving from side to side.

Two pairs of __________ hold solid food, tear it, and pass it to the mouth.

The second pair of maxillae also helps to draw water over the gills. Crayfish need water to flow over their ___________ so that they can breathe.

The first 3 appendages on the chephalothorax are _________. They hold food during eating.

The ___________ are the large claws that the crayfish uses for defense and to capture prey.

Each of the four remaining segments contains a pair of ___________________.

The first 5 segments of the abdomen each have a pair of __________________.

The _______________ create water currents and help with reproduction. Females attach ___________ to the last three pairs of swimmerets.

The 6 th segment of the abdomen has a pair of flippers or _______________.

In the middle of the uropods is the _________________.

On the ventral side of the telson is the ________________.

The uropod and telson together make up the ______________. The crayfish moves backward by forcing water forward with its tail fan.

Is your crayfish a male or female? Locate the base segment of each pair of walking legs. The base segment is where the leg attaches to the body. Study the inside surface of the base segments of the 3 rd and 4 th walking legs.

Male or Female? Female = observe a crescent-shape slit on the base segment of the 3 rd walking leg (genital pore) Male = sperm duct opening on the base segment of 4 th pair of walking leg.

Genital Pore