Gross Little Arthopods


You will be learning about the external and internal anatomy of a arthropods. You will focus on the organs, structures, and functions of the respiratory system. You will also understand the ecological role, human interactions, taxonomy, evolution, and body systems.

Background Info

The scientific name for crawfish is Cambaridae cambarus and for grasshopper it is Melanoplus differentialis. Crawfish live in freshwater with warm temperatures year round. Crawfish prey on dead algae, dead fish, worms, and dead insects. Grasshopper are herbivores feeding on a variety of plants. Some species only like grasses. Crawfish are omnivoric scavengers. Ecological advantages of crawfish is that they have tough exoskeleton and pincers. They affect humans by scavengeing for dead material decreasing waste in the environment.

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Crawfish belong to kingdom Animalia, phylum Arthropods, class Crustacean, order Decapod, family Cambaridae, genus Cambarus, and species Bartonii.


Crayfish adapted eyes on short stems that move around, allowing them to see in all directions just by turning the stems. They also have two pairs of sensitive antennae that help detect movement in the water as well as chemicals transmitted through the water, such as that of a dead fish or a nearby potential mate. Crawfish come in a variety of colors that tend to reflect their habitats. They might be dark brown to help hide under rocks, yellow to blend in with a sandy lake bottom or green to help camouflage them in underwater vegetation.

Interesting Facts

  • Crayfish can eat hot dogs and cat food.
  • There are 200 species of crayfish in North America.
  • Crayfish fight over their territory.

Respiration System

Aquatic arthropods possess gills for respiration. Although they vary in structure and location, the gills are always outgrowths of the integument (skin) and are therefore covered by the exoskeleton, which is thin in this area and not a barrier to the exchange of gases. Terrestrial arthropods possess tracheae and book lungs as respiratory organs. Tracheae are a system of tiny tubes that permit passage of gases into the interior of the body. In some arthropods the tracheal tubes are bathed by blood, but in insects the minute terminal endings (tracheoles) are embedded in the tissues, even within muscle cells. The small, external openings (spiracles) reduce water loss, the chitinous lining prevents collapse, and the small size of the arthropod and consequent short length of the tubule eliminates the need for moving gases in and out by active ventilation