External and Internal Anatomy of the Grasshopper Phylum Arthropoda by MikeJenny

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									                 External and Internal Anatomy
                      of the Grasshopper


                                                Phylum Arthropoda
                                                Subphylum Uniramia
                                                Class Insecta




Objective:

       To observe the external anatomy of the grasshopper
       To observe the internal anatomy of the grasshopper

Material:

      Preserved grasshopper
      Lab apron
      Gloves
      Goggles
      Dissecting tray
      Hand lens or magnifying glass

Day 1: External Anatomy
   1. Examine the outside of the grasshopper and note the three distinct sections of the
      body: head, abdomen, and thorax. (Refer to figure 1)
Figure 1: External features of the Grasshopper




Figure 2: Head view of grasshopper



2. Note the following features and which body segment of the grasshopper they are
   located on: (Refer to figures 1 and 2)

        Head
        Antennae (2)
        Compound eyes (2)
        Ocelli (simple eyes, 3, between compound eyes)
        Mouth parts: Palpus, Labium, Maxilla, and Mandible
             Abdomen
              Spiracles
              Auditory organs
              Ovipositor (on female only)

             Thorax
              Legs (3 pairs)
              Wings (2 pairs)


Since we will need to use these same specimens for the internal dissection next class, you
must preserve your crayfish properly. Wrap your specimen in a dampened paper towel,
place it into a plastic bag, and secure with a twist tie. Place your bagged specimen in the
container on the front counter. Once you have put the specimen away, clean off your lab
bench and equipment with Lysol (located at the sink).


Day 2: Internal Anatomy
Materials:

      Preserved grasshopper                           Hand lens or magnifying glass
      Lab apron                                       Scissors
      Gloves                                          Forceps
      Goggles                                         Scalpel
      Dissecting tray

Procedure:

   1. Use scissors to make an incision from the tip of the abdomen to the left of the
      middorsal line along the entire length of the grasshopper. Be sure to only cut
      though the body covering.

        *Keep the point of the scissors just inside the body and take care not to damage
        the internal organs

   2. Make a similar cut that runs up the front of the head and another one ventrally.

   3. If the interior spaces are filled with slender eggs, your specimen is a female

   4. Observe the many muscles of the grasshopper, mainly those connecting the wings
      and the legs.
5. Remove some of the lateral muscles and locate the following digestive parts:
   (Refer to figures 3)
      Crop                                            Colon
      Gizzard                                         Malpighian tubules
      Gastric area                                    Bellows
      Stomach                                         Accessory Gland
      Intestine
      Rectum

6. Locate the following body parts: (refer to figure 3)
      Heart – Circulatory system                        Testes and vas deferens or
      Trachea – respiratory                             ovaries and oviduct –
        system                                            reproductive system
      Brain – Nervous system
Figure 3: Internal anatomy of female (left) and male (right)

Follow Up Questions:
Answer the following questions on a sheet of loose leaf lined paper. Answers should
be in complete sentences.

1. Compare and contrast the function of the simple eyes to the compound eyes. (2
   marks)

2. What do you think the function of the large hind legs on the grasshopper are? (1
   mark)

3. What is the function of the spiracle? (1 mark)

4. Describe two traits that have allowed insects to be so successful. (2 marks)

5. What is the function of the crop? (1 mark)

6. Follow the path that food takes from the mouth to the anus of a grasshopper. (3
   marks)
Answer key:


   1. Compare and contrast the function of the simple eyes to the compound eyes. (2
      marks)

      Simple eyes: can sense changes in the amount of light but can not form clear
      images
      Compound eyes: may have up to several thousand lenses and forms many
      images. Brain combines images to show complete surroundings.

   2. What do you think the function of the large hind legs on the grasshopper are? (1
      mark)

      Function in jumping

   3. What is the structure and function of the spiracle? (1 mark)

      Small opening through which air enters the body

   4. Describe two traits that allow insects to be so successful. (2 marks)

      Ability to adapt to various food sources
      Ability to adapt to various habitats
      Small size allows them to hide easily and consume less food than larger animals

   5. What is the function of the crop? (1 mark)

      Storage

   6. Follow the path that food takes from the mouth to the anus of a grasshopper. (3
      marks)

      Mouth  esophagus  crop  gizzard  stomach  hind gut  Anus

								
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