The Oh, So Famous Arthropods

Arthropod Virtual Dissection Lab

Background Information

Crayfish, also known as Cambarus, are in the class Malacostraca and under the phylum Anthropoda and subphylum Crustacea. They are aquatic and live in freshwaters. Crayfish are mostly botton feeders that eat worms, insects, plants, and fish eggs. They also have predators such as snakes, raccoons, and opposums. Crayfish are nocturnal so they can see in the dark and have adapted to this ability. They also adapted to having appendages under the abdomen know as swimerettes.

The grasshopper is in the kingdom Animalia just like the crayfish and under the phylum Anthropoda and subphylum Hexapda. The scientific name for the grasshopper is the Caelifera and they are insects that usually live in meadows and fields. Grasshoppers eat plants and small insects. Birds prey on them and so do spiders, frogs, and many other rodents. Grasshoppers adapted to their habitat by growing hair on their abdomen, legs, and feet, which many seem peculiar, but they are used for hearing.

Today's Objective

Today, we will examine the external structures of the two preserved arthropods. Look for the similarities in these two organism that may be phylum traits & also look at the differences in these two organisms that may be class traits.

Respiratory System

The respiratory system begins with the gills that are located on the oustside of the body between the crayfish walla dn carapace. The gills take in oxygen from the water as it walks and the oxygen is then exchanged into the blood across the gill surface by circling around the branchial chamber. The circulatory system then works with the respiratory system and sends the oxygen away to the body for the crayfish.

For the grasshopper, the respiratory system begins at the ten spiracles located in the abdominal region and oxygen diffuses into the cells through the tracheae. The air sacs, which are similar to the alveoli, works as a temporary storage for the two gases ( oxygen and carbon dioxide ) when respiration occurs. The respiratory system works with the circulatory system by distributing the oxygen throughout the grasshopper body.

Human impact

The grasshopper population can decrease since they are considered pests. Grasshoppers eat crop and humans will probably try to get rid of them so they won't eat all the crops and plants needed for them to survive.

Some Crayfish are actually endangered now since they are a food source to humans. Humans catch them with nets and traps so their population will decrease and maybe disappear.

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