Amazing Arthropods

Venu Kantamani 04/07/14 Vu - PAP Bio

Objectives

In this lab, students will examine 2 preserved arthropods - a grasshopper and a crawfish. They will look for similarities in these 2 animals that may be phylum traits. They will also look for differences in these 2 animals that may be class traits.

Grasshoppers Background Information

Grasshoppers belong to the kingdom Animalia under the phylum Arthropoda, class Insecta, and order Orthoptera. The grasshopper's diet primarily consists of grasses, leaves, and cereal crops, but are also considered omnivorous. Its main predators are birds, lizards, spiders, and rodents. Ecological adaptations for grasshoppers include having jointed appendages, having 3 pairs of legs, having a chitinous exoskeleton, molting, big hind legs for jumping, and camouflage due to exoskeleton color.

Grasshopper Respiratory System

The respiratory system of the grasshopper consists of the air sac, spiracles, dorsal and ventral tracheal trunk, visceral branch and ventral branch. The spiracles first take in air from the atmosphere. The spiracles open into small spaces called atria that continue as air tubes called the tracheae. The tracheae join together to form the dorsal, ventral, and lateral tracheal trunks. At some places, the trachea enlarge to form air sacs which are devoid of cuticle and serve to store air.

Grasshopper Interesting Facts

Grasshoppers migrate in groups.

Grasshoppers change their chirping based on the temperature.

Young grasshoppers can eat twice their own body weight in one day.

Crayfish Background Information

Crayfish belong to the kingdom Animalia under the phylum Arthropoda, class Malacostraca, and order Decapoda. The crayfish's diet primarily consists of fish, shrimp, water plants, worms, insects, snails, plankton, and even dead plants and animals. Its main predators include alligators, fish, and some types of turtles and birds. Ecological adaptations for crayfish include having jointed appendages, having 3+ pairs of legs, having a chitinous exoskeleton for shelter against predators, and molting.

Crayfish Integumentary System

The integumentary system of a crayfish consists of the antennae, antennules, rostrum, carapace, cheliped, walking legs, telson, and uropod. The crayfish's body is divided into 2 sections: the cephalothorax and the abdomen. The antennae and antennules are used for tactile and olfactory sensations. The rostrum is an extension of the shell of the crayfish. The carapace is the shell itself. The cheliped is used for grasping food. Walking legs allow the crayfish to move around. Swimmerets are used by males to transfer sperm to females and by females to hold eggs and young. The telson and uropod are both used for swimming.

Crayfish Interesting Facts

Crayfish are often caught using traps.

Crayfish live on every continent except Africa and Antarctica.

There are 200 species of crayfish in North America.

Crayfish have inner gills that allow them to live out of water.