Arthropod Army

Arthropod Virtual Dissection Lab by: Tina Liu-Vu-PAP Bio-4


In this lab, students will examine two preserved arthropods – a grasshopper and a crayfish – and look for both similarities and differences amongst the two animals that may classify the two arthropods into separate phylums and classes.

Caelifera - The General Information

How do we classify a grasshopper? The grasshopper, is in the Kingdom Animalia, Phylum Arthropoda, Subphylum Hexapoda, Class Insecta, Order Orthoptera, and Suborder Caelifera.

What habitats do grasshoppers live in? Most grasshoppers prefer dry open habitats with lots of grass and other low plants, though some species live in forests or jungles. Many of the grassland species invade farmer's fields too.

What adaptations have grasshoppers made to survive better in the environment? - Grasshoppers usually have large eyes, and are colored to blend into their environment, usually a combination of brown, gray or green. In some species the males have bright colors on their wings that they use to attract females. A few species eat toxic plants, and keep the toxins in their bodies for protection. They are brightly colored to warn predators that they taste bad.

Grasshoppers: its predators and prey

Big image

Evolutionary relationship of a grasshopper (cladogram)

Grasshoppers are placed in the order Orthoptera, which is distinguished by its biting mouth parts.
Big image
Grasshopper Dissection
Click here for more about the systems in a grasshopper

Click here for more information about the respiratory, digestive, reproductive, circulatory, and nervous system of a grasshopper!

Respiratory System

The exchange of gases in a grasshopper happen through the tracheal system but begins at the spiracles where air is taken in first. This system contains of ten spiracles located in the abdominal area and the others are thoracic. Oxygen diffuses into cells directly into the atmosphere and that completes the grasshoppers process of respiration. The air sacs that the tracheal system works to create can be compared to human alveoli because it stores carbon dioxide and oxygen when the respiration is taking place. However, we take air in from our mouths and nose while their spiracles do that with the control of their brains. A few of the spiracles are involved in the expiration of air as well. The grasshoppers tracheal system works as an independent function not involving the circulatory system. The respiratory system provides the oxygen to keep the body functions running by distributing oxygen through the circulatory system.
Big image

Grasshoppers year-round

This map shows where grasshoppers are concentrated in the United States during the seasons.


Grasshoppers are found on all continents except Antarctica. There are over 10,000 species of grasshoppers known, about 50 of which are found in Michigan.
Most grasshoppers can only survive the winter as an egg; the adults all die when it gets cold.
No grasshoppers are known to be endangered.

Human Impact

In high densities, grasshoppers can severely reduce the forage value of rangeland. Their feeding causes direct damage to plants' growth and seed production, thus reducing valuable forage and feed for wildlife and livestock. Other effects include: soil erosion and degradation, disruption of nutrient cycles, introduction of invasive plants, interference with water filtration, and potentially irreversible changes in the flora and fauna of the rangeland ecosystem. This can severely damage a farmers' crops and land and possible ruin his or her's business.

Crustacea - the general information

How do we classify crayfish? Crayfish are classified into Kingdom Animalia, Phylum Arthropoda, Subphylum Crustacea, Class Malacostraca, Order Decapoda, and Suborder Pleocyemata.

Where do crayfish live? Rivers and brooks are the main living habitat for the crayfish due to their water clarity and thin ice conditions. Freezing water conditions are enough to destroy crayfish habitat and that’s a main reason they thrive in rivers of moving water.

What adaptations do crayfish have? Crayfish have two big pincers that help tear food apart. When threatened, crayfish often raise their pincers high and wave them around. Some also use their front pincers to help dig burrows. If a crayfish loses a leg or pincer, it grows back, usually during the animal's next molting cycle.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.

Crayfish: the friends, the foes, and the food

Big image

Evolutionary relationship of the crayfish (cladogram)

Crayfish are sorted into the class Malacostraca, because the crayfish are close relatives to the crab, the crab is shown on the cladogram.
Big image
Crayfish Dissection
Learn more about the crayfish anatomy

Interested in learning more about the functions, inside and out of the crayfish? Click the button!

Respiratory System

The gills of the crayfish are located on the outside of the body between the crayfish body wall and carapace. If you were to detach one of the crayfishes walking legs, you would observe that the crayfish's gill is attached to its walking leg. The crayfish's gills are attached to the walking legs, so as it walks, it can breath.A crayfish has a pocket where water is stored. The water is stored so the crayfish can walk on land and still breath. A crayfish has to have water in order to breath. As the crayfish walks, the surface area of the gills spread so the water can pass through in order for the crayfish to breath.
Big image

Map of the concentrations of crayfish in the United States

We can tell from the map that in the Ohio region, is where the native region of crayfish began blooming out towards the Wisconsin area.


Did you know...
Over 350 of the 500 total crayfish species lives in the United States alone
Crayfish are also called craw-fish, crawdads and mud bugs.
Crayfish live on every continent except Africa and Antarctica.
The colors of a crayfish can be sandy yellow, pink, red, dark brown, and blue.

Human Impact

Some species of invasive crayfish can cause additional damage to river systems by constructing burrows in the banks leaving them prone to collapse. This presents a hazard to human health and safety by weakening walkways and of the river side and impacts on the flood defence of the areas affected.

Works cited