Dissection of a Grasshopper

What is a grasshopper? A grasshopper is an arthropod. It has Jointed appendages A segmented body An exoskeleton

Grasshopper Facts: Country: Worldwide Habitat: meadows, fields, and hedges Length: up to 3 in. (8cm) but mostly 5/8 -1 1/8 in. (15-30 mm) Weight: almost nothing Closest relative: katydid and cricket

Why dissect a grasshopper? To identify the external and internal anatomy of the grasshopper To practice basic dissection skills

Explore this site to learn more about grasshoppers. http://www.ris.net/~lawnman/hopfaq.html#GUTS

Get ready to learn more as we dissect a grasshopper!

Step One Identify the materials you will need for your dissection. Dissection Tray Hand lens

Materials, continued Ruler Scalpel Scissors Eye dropper Dissection pins Forceps (tweezers)

Materials, continued Gloves Goggles And a grasshopper!

Study the external parts of the grasshopper

Step Two: Identify the Head Thorax Abdomen Notice also the eyes, antennae, legs and wings

Skeleton The grasshopper has a hard exoskeleton. That means its skeleton is located on the outside of its body, not internally like ours. This skeleton is made of chitin, a carbohydrate.

The head

A Frontal View of the head

The compound eye The grasshopper has two compound eyes that are made up of hundreds of individual eyelets.

Observe the antennae The grasshopper's head has two antennae that are able to feel and smell what is nearby.

The mouth The mouthparts are a set of movable jaws that let the grasshopper chomp its way through grass blades.

The mouth Labrum - the broad upper lip Hypopharynx - the tongue Mandibles - two heavy blackish jaws with teeth along the inner margin. The mandibles move up and down. Maxillae - two smaller jaws that move side to side Labium - the lower lip Palp - maxillary and labial palps are sensory appendages

The thorax

The legs Using huge hind legs, the grasshopper makes gigantic leaps into the air. Long legs are an advantage for jumping, because they increase the distance over which the jumper can push off the ground

The legs, continued When a grasshopper jumps, it first crouches down, there is then a short delay, and then off it goes. Back leg- knee

The leg, continued The two rear legs are specialized and strengthened for jumping, while the front two pairs are used only for walking on the ground

The Wings The two pairs of grasshopper wings differ in shape, structure, and function. The hind pair are responsible for flight.

Close up of the wings After its spring-assisted takeoff, it can unfurl its two pairs of wings and continue flying with them.

The abdomen The hind region of the grasshopper’s body, the abdomen, consists of 11 segments.

The Abdomen The abdomen is built up of a series of upper plates known as 'tergites' and lower plates known as 'sternites‘. It is held together by a tough yet stretchable membrane

Determine the sex of your grasshopper

Close up Female Male

Reproductive organs Female

Reproductive organs Male

Task Draw a diagram of the external parts of the grasshopper. Label at least the following: Head Thorax Abdomen Compound eye Antennae Wings (forewing and hindwing) Mouth

Step Three: Measure

Measure Be sure to record the length of your grasshopper. Measure the grasshopper from the tip of the head to the end of the abdomen. We will collect these measurements at the end of the dissection lab and compare!

Step Four: The Dissection begins: Position the grasshopper dorsal side up Carefully remove the protective sheath from the scalpel. Hold the grasshopper firmly.

Cut along the dorsal surface of the thorax and abdomen

Gently pull the exoskeleton aside

You may wish to use the dissection pins to make viewing easier.

Using a hand lens, identify as many of the internal organs as possible

Digestive System These are the parts of the digestive system : Mouth Esophagus Crop Stomach Intestine Chewed food is stored in the crop, digested in the stomach, and absorbed in the intestine.

Observe the digestive system

A little closer

The crop, gizzard and digestive caecae The digestive caecae produce enzymes which aid in digestion

Respiratory System You will probably NOT be able to see the small holes. on the side of their bodies without your hand lens. These holes are called spiracles, each hole leads to a large tube called a trachea. The large tubes divide into small tubes that branch out to all the cells of the body. This system of tubes carries oxygen to the cells and takes away the carbon dioxide.

Respiratory System Do you see anything in your grasshopper that resembles a lung?

Respiratory System The grasshopper does not have a lung. How then does it breathe? Air enters the spiracles and as the abdomen expands and contracts, fresh air moves in and used air moves out. The air enters the cells directly and is not transferred to the blood- that’s why their blood is yellow, not red- it contains no hemoglobin!

Circulatory System The grasshopper’s circulatory system is open- that means that it does have a “heart”, but the heart is more of a muscular tube that collects the blood and forces it to the front of the body. The blood freely flows throughout the grasshopper

The Nervous System The grasshopper's brain is located between its eyes, above the esophagus.

Cool fact… The grasshopper does not use its brain to walk or jump! It does that without a brain. The brain is used to control the mouth and to send sensory information to the rest of the body.

Excretory System There are a number of tubules between the large intestine and the stomach. The outer end enters into the body cavity and takes in the wastes. The wastes are carried into the large intestine and out through the anus.

Task Draw a diagram of the internal organs you identified. Include at least the following: Intestines Crop Reproductive organs

Be sure to: Properly dispose of your grasshopper Remove the dissection pins. Pick up the grasshopper and any organs that you may have removed. Discard them into the plastic bag provided. Be sure to dump the remaining liquid in the jar as this is the last dissection. Sanitize scalpels and pins, rulers and hand lenses and trays. Return them to the kit. Wipe down lab tables and discard gloves.

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