Arthro-whats? Arthropods!

Arthropod Lab March 14, 2014- Zhengde Du

Cambarus

Crayfish are in the Kingdom Animalia. They are under the phylum Anthropoda and subphylum Crustacea. They are also called the Cambarus, which is a genus. Crayfish are aquatic and live in freshwaters. They are bottomfeeders and eat worms, insects, plants, and fish eggs. Since they have many predators after them, like snakes, opposums, and raccoons, they are nocturnal, which is an adaptation. They have also adapted to the aquatic life by having appendages under the abdomen called swimerettes.

Caelifera

The grasshopper is in the kingdom Animalia as well. It is under the phylum Anthropoda and subphylum Hexapoda. The most specific name for the grasshopper is Caelifera, which is a sub order. Grasshoppers are insects that usually live in meadows and fields. They eat plants and other small insects; they are preys to birds, spiders, frogs, and rodents. Grasshoppers have adapted to their habitat by growing hair on their abdomen, legs, and feet, which are used for hearing.

Objectives

Today, we will examine two preserved arthropods, look for similarities in these two animals that may be phylum traits, and look for differences in these two animals that might be class traits.

The Respiratory System

Crayfish-

The respiratory system starts with the gills, which are located on the outside of the body between the crayfish body wall and carapace. The gills take in oxygen in from the water as the crayfish walks. The oxygen is exchanged into the blood across the gill surface by circling around the branchial chamber. The circulatory system then sends the oxygen away to the body.

Grasshopper-

The respiratory system starts at the ten spiracles located in the abdominal region. Oxygen diffused into the cells through the tracheae. The air sacs, similar as 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 to distribute the oxygen to the body.

Human Impact

Grasshoppers-

The grasshopper population can significantly decrease, as grasshoppers are considered pests, since they eat crops. Humans get rid of them so they won't eat all of our crops and plants.

Crayfish-

Some crayfish are endangered now, as they are a food source to humans. We catch them with nets and traps, and so their populations have also decreased significantly.

Have you learned a lot about arthropods? Take this quiz to find out!