Arthropod Dissection


April 6, 2014 By Jackson Twyman

Caelifera (Grasshopper) and Astacoidea (Crayfish)

The Caelifera lives in high grasses, and in forests or jungles. Grasshoppers like to eat many varieties of plants, but some species only eat grasses. Their predators are birds, spiders, lizards, and rodents. Grasshoppers keep the number of plants in control, and they provide food for many species. Grasshoppers have large hind legs to jump, and wings to fly.

Crayfish like to live in freshwater that doesn't freeze over in the winter. Fish, birds, alligators, and people are the crayfish's predators. They eat the easiest food to find, like dead fish, insects, worms, and anything it can find. The crayfish scavenge off of the bottom of any fresh water body. The crayfish have pincers used to grab prey, and take pieces of meat off of dead material. Also, they have a strong tail used to get away from predators.


Today you will learn about two arthropods. One of them is a grasshopper, and the other is a crayfish. You will learn about their external anatomies, and its parts. The system you will learn about these two organisms is the skeletal system.

Click for more information on arthropods.

Skeletal System

Skeletal System

The grasshoppers skeletal system consists of a three part body containing the thorax, abdomen and head. The body is segmented to allow the insect to move more easily. The thorax contains three pairs of legs, 2 for walking, and 1 for jumping. The grasshoppers skeleton is an exoskeleton, meaning that it is outside of its body. Their exoskeleton is made of chitin. This system is designed to protect its internal organs from the outside world. This protects all of the other body systems in the grasshopper. Also, the skeletal system is used for moving.

Crayfish have an exoskeleton, that is broken up into three segments. These are the head, the thorax, and the abdomen. The thorax contains 4 pairs of walking appendages. The exoskeleton is made up of chitin, proteins, and lipids. Also, it is segmented allowing the crayfish to swim with ease. The crayfish has a cheliped which is used as scissors for defense. The exoskeleton provides homeostasis to the crayfish. Also, the skeletal system protects all of the other systems from being harmed by the outside world.

For more information on arthropod skeletal systems, click this link.

Arthropod Cladogram

Interesting Facts

Grasshoppers and locusts are the same thing. They have ears on their bellies. Grasshoppers make music by crepitating. They cause the loss of billions of dollars in crops each year. People eat grasshoppers for protein. They existed before the dinosaurs. For defense, they spit brown liquid.

When crayfish molt, they eat their old skeleton for the leftover protein. They are able to live from 20 to 30 years. Crayfish claws are able to grow back. Crayfish are cousins of the lobster. Crayfish are used for food by many people throughout the world for their good flavor.