1. How does chemical messengers help to maintain homeostasis in the body?
1. After school help on Thursday
2. Work on your homework packet- don’t save it all for the last minute! It’s due Friday
3. Quiz Ch 17 on Friday
Identify the neurons in the diagram and their function.
Starred thought of the Day
*Know your limits; push them.*
Today we dissected the grasshopper in lab. This lab identifies different parts of Insects and works to get you comfortable with dissections. I was using two resources on the SMARTboard. This website- http://www.biologyjunction.com/grasshopper_dissection.htm and this picture: http://biology.unm.edu/ccouncil/Biology_203/Images/Protostomes/grassdis1.jpg
Grasshopper Dissection Lab
Background Information –
There are more than 1 million species of insects on the Earth. Insects have three body parts: the
head, the thorax and the abdomen. Insects have one pair of antennae on the head, and three
pairs of legs on the thorax. Most adult insects have one or two pairs of wings attached to the
One team member will read the directions aloud while the other works, switching roles as often as
they wish. The reading aloud is required.
1. External structures and body plan – Place a lubber grasshopper in a dissecting tray. Use
your hand lens to observe the grasshopper carefully.
2. Locate the following on the grasshopper, check off each as you work
o Head – first body region
o Eyes – the grasshopper has two compound eyes and three simple eyes.
o Antennae – sensory organs used to feel and smell
o Palps – mouth parts that grasp food; found under the jaw
o Mandible – jaw used to crush food; found at the bottom of the head
o Thorax – second body region
o Legs – all insects have six legs.
o Tympanum – (eardrum) small drum-shaped structures on either side of the thorax.
o Wings – Locate the two pairs of wings.
o Abdomen – third body region. 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.
o Spiracles –the tiny openings along the abdomen. These are breathing pores through which
oxygen enters and carbon dioxide leaves.
3. Label the diagram of the grasshopper:
4. Locate all six legs. Are there any missing? If so, why might this be?
5. Observe the exoskeleton. Is it in one large shell or in many smaller sections?
4. Inspect the 2 compound eyes and 3 simple eyes with the hand lens. Add the simple eyes to
5. Locate the tympanum and add it to your diagram.
Wait for further instructions; do not cut into your grasshopper until told to do so!
Internal Anatomy – Check off each of the following as you work, use the diagram to help
you identify the organs.
o Position your grasshopper dorsal side upward.
o Cut along the dorsal surface of the thorax and abdomen and pull the exoskeleton aside.
Be sure to keep your scissors close to the body wall to avoid damage to the internal
o Cut through the exoskeleton over the top of the head between the left antenna and left eye
to the mouth. Remove the exoskeleton on the left side of the head.
o Locate the large dorsal blood vessel.
o Locate the finely branched trachea leading to the spiracles.
o Find the brain and the ventral nerve
o The digestive system fills most of the internal cavity of the grasshopper. A muscular
tube, the esophagus, carries food from the pharynx into a large storage organ, the
crop. Chewed food is stored in the crop. Next is the stomach to which are attached six
double fingered-shaped digestive glands, the gastric caecae, which produce enzymes
that are secreted into the stomach to aid in digestion. The digestive tract continues as the
intestine, it leads to the short rectum which opens to the exterior via the anus. The hair-
like tubules lying over the intestine are Malpighian tubules, the excretory organs, which
collect wastes from the blood.
1. Summarize the main characteristics of insects, how do we distinguish them from other
2. Describe the “feet” and legs of the grasshopper. Are the three pairs of legs identical?
Predict what task each type of leg might be used for. A diagram may aid your answer.
3. Identify and describe, in detail, three ways that humans and grasshoppers are anatomically
4. Identify and describe, in detail, three ways that humans and grasshoppers are
5. Compare the grasshopper with the earthworm. Explain which characteristics make the
grasshopper well adapted for its life on dry land, and which characteristics make the worm
well adapted to life underground.
Grasshopper Dissection due Monday
Work on HW packet- Due Friday
Study for Quiz Ch 17 on Friday