Grasshopper Dissection

ArthropodsArthropods make up the largest phylum of animals in theanimal kingdom. Arthropod means “jointed foot”. Allarthropods have jointed appendages. Arthropods alsohave segmented bodies and an external covering called an exoskeleton.

Insects

Insects are one type of arthropod. Insects have threebody regions: a head, a thorax, and an abdomen.

All insects also have six legs, one or two pairs of wings,one pair of antennae, and a pair of compound eyes.

Six Legs

Antennae

CompoundEyes

Parts Of The HeadUse the diagram below to identify the parts of the headon your grasshopper.

The grasshopper has 5 eyes, two compound eyes andthree simple eyes. The antenna are sensory organs located on the head.

Mouth PartsUse the diagram below to identify the mouth parts on your grasshopper. As you identify each part, try and remove it with your tweezers.

The labrum is used to hold food. The mandibles are teethused to chew food. The maxilla are used to chew and taste food. The labium is used to hold food while it isbeing chewed. Now use the diagram below to locate theexternal structures on your grasshopper.

A grasshopper’s eardrum, or tympanum, is located belowthe second pair of wings on each side of the thorax.Locate the tympanum on your grasshopper using thepicture below. The tympanum is used for hearing.

tympanum

Like all insects, grasshoppers have six legs. The front pairare used for walking, climbing, and holding food. The middle legs are also used for walking and climbing. Thehind legs are used for jumping.

Grasshoppers breath through tiny holes in their abdomencalled spiracles. Try and find these tiny holes along eachside of the abdomen.

close up of one spiracle

A female grasshopper has a longer abdomen than a malethat ends with a four pointed tip called an ovipositor.The ovipositor is used to lay eggs. Look and the end ofyour grasshopper’s abdomen and determine if it is amale or a female.

Internal Structure

Using your scissors, remove the three left legs. Next,snip the end off the abdomen and insert the tip of yourscissors under the top surface of the abdomen. Cutstraight up the middle of the abdomen all the way to the head. Only cut as deep as the exoskeleton or youwill cut through the organs.

Next, cut the same way up the bottom surface of the abdomen to the mouth. Remove half of the exoskeleton and pin it open as shown on the next slide. Locate all the organs shown on the next slide.

start cutting herestop cutting here

gizzard

brain

esophagusrectum

anus

heart(ovary)

The esophagus is used to swallow food. The crop, gizzard,gastric ceca, stomach, large intestine, and small intestineare digestive organs. The rectum stores waste and theanus removes wastes from the body. The malpighan tub-ules collect waste from the blood. In the female grasshop-per the ovaries produce eggs. The testes produce spermin the male grasshopper.

Throw the grasshopper away, wipe your dissecting toolsoff, wipe your tray out, and wash your hands with soapand water. Answer the following questions on a sheet of paper.

Questions & Conclusions1. What is the largest phylum in the animal kingdom?2. What does “arthropod” mean?3. List three characteristics that all arthropods have.4. What three body regions do all insects have?5. Name four other characteristics that all insects have.6. How may eyes does a grasshopper have?7. What are the antenna used for?8. How may different mouth parts does a grasshopper have?*more questions on next slide

9. Describe the function of the following mouth parts: a. labrum- b. mandibles- c. maxilla- d. labium-10. What is the tympanum?11. Where is it located?12. How many legs does a grasshopper have?13. Describe the function of the legs: a. front legs- b. middle legs- c. back legs-14. What are the spiracles used for and where are they located?*more questions on next slide

15. What is the function on the ovipositor?16. Was your grasshopper a male or a female?17. Describe the function of the following organs: a. esophagus- b. rectum- c. anus- d. malpighan tubules- e. ovaries- f. testes-18. Name the six digestive organs in a grasshopper:19. Why is a grasshopper classified as an invertebrate?20. How is a grasshopper’s skeleton different from yours?21. List the animals we have dissected so far from least complex to most complex: