Arthropod Dissection

Jonathan Dorsey / Period 7 / Guzman

Objectives

Students will be learning about the external anatomy of arthropods. Our focus will be on the integumentary system, and the external features on the grasshopper and crayfish.

Background Information

The grasshopper, or suborder Caelifera, live all throughout North America in tall grasses. The grasshopper eats a variety of plants, mainly focusing on shrubs and grasses. Its predators are birds, lizards, mantids, spiders, and rodents. Grasshoppers are primary consumers, seeing as they are herbivores. They have adapted to have valves on their abdomen which they use to dig holes to lay eggs in. Grasshoppers have many beneficial aspects towards humans. For example, they fertilize plants through their abundant wastes. However, grasshoppers have been known to destroy whole fields of cropland throughout the Midwest.


The crayfish, or superfamily Astacoidea, live across the world in freshwater habitats. Most, however, reside in North America. The crayfish has adapted to have strong pinchers that it uses for cutting and grabbing hold of objects. Crayfish prey on snails, algae, insect larvae, worms, and tadpoles, and some vegetation, making them secondary consumers and omnivores. Their predators are alligators, cod, chicken turtle, painted turtle, desman, and birds. Humans have all sorts of uses for crayfish. Crayfish are extremely important in gamefish diet, feeding a large population of the fish we fish recreationally. Also, crayfish are a delicious food served all across the world.

Additional Information

Crayfish are closely related to the lobster. There are over 500 different species of crayfish. Only a select few species live in salt water. The largest crayfish, Astacopsis gouldi, can weigh up to eight pounds!


Grasshoppers have no wings in their young stage. Some grasshoppers spit brown liquid as a defense mechanism. During molting, grasshoppers inhale large amounts of air to build up pressure and split the exoskeleton.

Arthopod Cladogram

Crayfish: Crustacea

Grasshoppers: Hexapoda

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