Arthropod Lab

Arthropod Observation- Vu- PAP Bio


Arthropods are known for having segmented bodies and joined appendages. Examples of arthropods are astacoidea, or crayfish and caelifera, grasshoppers. Crayfish, a type of arthropod resembling a lobster that live in lakes, ponds, streams, and rivers across the country. Crayfish feed on small fish that they catch with their claws, plant matter, and almost anything around them. They usually feed on any decaying matter that falls to the bottom of their habitat. Some predators to crayfish are raccoons, turtles, possums, muskrats, and blue gill fish. Humans are the biggest predator of the crayfish and have caused them to go endangered. Grasshoppers live in grass, hince the name grasshopper. While some can be omnivorous, they are herbivores and feed on mostly grass, leaves, and cereal crops. Grasshoppers have many predators, some include, turtles, lizards, fish, chipmunks, and toads. There job is to fertilize the soil around them and serve as food for animals.

Parts of A Crayfish

Respiratory system in a Grasshopper

Respiratory System - at a Glance

Insects need oxygen and use the same metabolic processes as humans (such as the Krebs cycle) to undergo it. In insects, air enters into the body through small valves in the exoskeleton called spiracles. Air then enters a longitudinal tracheal trunk and goes through a long complex system of tracheal tubes whose job is to act as an airway to maintain an adequate exchange of oxygen and carbon dioxide. At the end of each tube is a tracheole which provides a moist place for the exchange of gas between the air outside and a cell in the insect. Oxygen dissolves the liquid in the tracheole and diffuses it into the cytoplasm of a near cell. At the same time, carbon dioxide is produced as a waste product of cellular respiration and diffuses out of the insect back through the tracheal system and out the spiracles. Unlike most animals, arthropods have no single major organ used for respiration. While most arthropods use the tracheal system, some use a system that involves book lungs, a series of leafy like plates that reside within a chamber. This is common in arthropods such as spiders and chelicerates. Book lungs can work along with tracheae, or they can function in exchange of it. All of these structures are only found in arthropods and onychyphora. Crustaceans lack these structures and undergo their respiratory process with their gills.


Students were given an opportunity to observe two animals from the phylum anthropoda, a grasshopper and a crayfish. They were able to see and recognize common characteristics of the phylum such as number of leg pairs, segmentation, and number of antennae. If a student did not know what any of those were, they were able to see it in person rather than looking a a photo, which may be unclear. This lab provided students with the opportunity to see local arthropods up-close and gave them a chance to interact with them and learn from it.