Dissection of a Grasshopper Kathy Biernat May 2007
What is a grasshopper? A grasshopper is an arthropod. It has • Jointed appendages • A segmented body • An exoskeleton
Grasshopper Facts: Country: WorldwideHabitat: meadows, fields, and hedgesLength: up to 3 in. (8cm) but mostly 5/8 -1 1/8 in. (15-30 mm) Weight: almost nothingClosest 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
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!
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 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 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
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
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.
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.
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?