Land Lubber Grasshopper Dissection

http://www.google.ca/searchhl=en&pwst=1&rlz=1R2GGIE_en&defl=en&q=define:Cephalization&sa=X&ei=4ZwSTeS_OZC-sQOsqtS6Ag&ved=0CBUQkAE

• Grasshoppers are from the phylum Arthropodia and the class Insecta
• Cephalization - over many generations, the nervous tissue becomes concentrated towards one end of an organism. In this case the nervous tissue of a land lubber grasshopper has cephalized toward the anterier end, making sensory organs (eyes and antennae).
•  Eyes ( http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CompoundEye.html , http://en.wikipedia.org/wiki/Simple_eyes_in_invertebrates )

- Two huge compound eyes that have many ommatidia on them (each one is a visual receptor). Each ommatidium consists of a lens (single facet), a crystalline cone, light-sensitive visual cells (arranged in radial pattern and pigment cells (separate the ommatidium). The compound eye is great at detecting movement. The compound eye can also respond to ultraviolet light (we can't see this light).



A diagram of a compound eye. You can slightly see the
ommatidium on the eye in the picture to the left.





Compound eyes and antenanae
are a result of cephalization







.

- Three small simple eyes (dorsal ocelli) that consist of a cornea (lens) and a layer of photoreceptors (rod cells). The ocelli are far more sensitive to light. The diagram below shows where on a grasshopper head the ocelli are located.

• Mouth ( http://en.wikipedia.org/wiki/Insect_mouthparts )

A Diagram of the Grasshopper Mouthparts

- Mandibles - crush, tear, cut and chew food  

- Maxillae - manipulate food during mastication (chewing)

- Maxillary and Labial Palps - sensory receptors for sensing characteristics of food

- Labium - the floor of the mouth, assists chewing

- Hypopharynx - assists swallowing

- Labrum - upper lip

• Thorax ( http://www.biologyjunction.com/grasshopper_dissection.htm , http://wiki.answers.com/Q/Function_of_spiracles_in_grasshopper )

- Two wings - the outer wings protect the flying wings

The Bottom wing is the protecting wing

- Legs - The first two pairs are for walking and the last pair is for jumping. You can see the different legs in the photo below.

 

A jumping leg from a land lubber grasshopper. This is an example of a jointed appendage.

• Abdomen

- Spiracles - used for respiration. Oxygen comes in and is filtered by tracheae, it is distributed among the cells and then carbon dioxide it taken out.

- Difference between male and female - a female grasshopper has a ovipositor. A comparison is shown in the diagram below.



If you compare this picture with the diagram to the right, you can see that our grashopper is a male.