Grasshopper Observation and Dissection

Grasshopper Observation and Dissection

Background Information: Grasshoppers are members of the phylum Arthropoda. Grasshoppers belong to the phylum arthropods and to the class insects. There are more than 900,000 species of insects. They are mainly land animals and occupy almost every environment on land. The development of wings gave grasshoppers advantages over other land invertebrates. They could spread out into new areas, they could search larger areas for food, and they were able to fly away and escape from predators.

Grasshoppers have an exoskeleton composed of chitin. They have three pairs of jointed legs. The front pair are used for walking, climbing, and holding food. The middle pair are used for walking and climbing. The back pair of legs are used for jumping. There are three distinct body regions, the head, the thorax, and abdomen. The head is used for eating and sensing, the thorax is used for movement, and the abdomen has the digestive and reproductive organs.

Two pairs of wings are attached to the thorax. Grasshoppers have one pair of antennae that is used for sensing, one pair of large compound eyes that detect movement, and three simple eyes that detect light and dark. Tympanum, or eardrums, on the thorax are used for hearing. The grasshopper's spiracles and air tubes provide a way for getting oxygen into the body and removing waste gasses from the body. Grasshoppers lay a large number of eggs, and the eggs hatch very quickly. This allows the grasshopper population to increase rapidly.

External Observation

1. Locate the head, thorax, and abdomen.

2. Observe the head. Locate the two compound eyes and the three simple eyes.

3. Identify the mouth parts. Use your magnifying glass to locate:

Labrum: hinged upper lip that holds food

Mandibles: crushing jaws

Maxillae: chew and taste food

Labium: hold food while being chewed

4. Locate the typamum, or eardrums, on the thorax.

5. All insects have six legs. Locate: Front Legs Middle Legs Back Legs

6. Locate the two pairs of wings.

7. Find the tiny openings along the abdomen called spiracles.
These are the breathing pores through which oxygen enters and carbon dioxide leaves.

8. A female grasshopper has a much longer abdomen than a male.
It ends in a four-pointed tip called an ovipositor through which eggs are laid.

Grasshopper Dissection and Internal Observation

The grasshopper's digestive tract is specialized to eat plant tissue. The mouth parts hold, crush, and chew the food before it passes into the mouth. From the mouth the food passes through the esophagus into the crop. The food is stored in the crop. Next, food moves into the gizzard, where teeth made of chitin grind it up further. Food then moves into the intestines where glands digest the food. and other structures absorb the digested food. Undigested food then goes to storage in the rectum, and then is eliminated out the anus.

Internal structure

1. Remove the three right legs.

2. Insert the point of your scissors under the top surface of the last segment of the abdomen and make a cut to the right of the mid-dorsal line all the way to the head. Be careful not to cut the organs underneath.

3. In front of the thorax, cut down the right side to the bottom of the grasshopper.
Cut down between the next to the last and last abdominal segments.

4. Remove the exoskeleton from the right side of your grasshopper.

5. Locate the large dorsal blood vessel that runs down the grasshopper's body.

6. Remove ovaries from the grasshopper. These look like maggots or brown rice.
Eggs are produced in the ovaries.

7. Remove the muscles of the abdomen. Can you see the air tunes?
8. Carefully cut away muscle and tissue to expose the digestive system.

9. Locate the parts of the digestive system: Mouth, Esophagus, Crop, Gizzard, Stomach, Intestine, Rectum, Anus

Draw what you see in the digestive system and label the drawing.

Questions Names:______

HR: ______Date: ______

Answer the questions below. You can divide the questions among the team members to find the answer.

Name the three parts of a grasshopper's body.

1. ______2. ______3. ______

4. What eyes does a grasshopper use to detect moving objects? ______

Name four functions of the mouth parts of the grasshopper.

5. ______6. ______7. ______

8. ______

Name two functions of the head.

9. ______10. ______

11. Which legs are used for jumping? ______

12. Which legs are used for walking, climbing, and holding food? ______

13. Which legs are used for walking and climbing? ______

14. Can you drown a grasshopper by holding its head underwater? ______

15. The grasshopper belongs to the Phylum ______

16. The grasshopper belongs to the Class ______

17. Which of the 5 Kingdoms does the grasshopper belong to? ______

18. Name one reason a grasshopper population may increase rapidly. ______

Draw and label the parts of the grasshopper's external and internal body.