Monday, December 1

Crayfish/Grasshopper Worksheet

NOTE: The worksheet and lab write-up has been combined in this post because they both cover the exact same thing.

The following link will emphatically provide you with the correct answers:

Los Answers

The following is the (incomplete) lab write-up for the crayfish and grasshopper dissections:

Grasshopper/Crayfish Lab

Purpose: Compare and contrast the grasshopper's and crayfish's structres in relation to their environment.

Problem: How do the structures of a crayfish and grasshopper compare and contrast in relation to their environment?

Hypothesis: The crayfish's body will be more suitable to acquatic environments; contrasting the body structure of the grasshopper which will be more suitable for terrestrial environments.

Materials: *1 Grasshopper*1Crayfish*1Dissection Scisson*1 Dissection pan*2 probs*Numerous dissection pins*Plastic gloves*Lab apron*Tape*Black marker

Procedure Grasshopper
Place the grasshopper in the dissecting tray. Locate the head, thorax, and abdomen. Observe the grasshopper carefully.Make a cut to the left of the mid-dorsal line. Be careful not to cut the organs underneath. In front of the thorax, cut down the left side to the bottom of the grasshopper. Cut down between the next to the last and last abdominal segments.Use your forceps to pull down the left side. Locate the large dorsal blood vessel.Use your scissors to cut the muscles close to the exoskeleton. Locate the finely branched trachea leading to the spiracles. Use forceps to pull skeleton apart, exposing internal systems. With dissecting pins, tack the flaps to the tray, thus keeping the body cavity open.Locate and identify structures associated with the internal morphology of insect.

CONCLUSION: Identify similar structures and shape and explain whe they may have these similarities:(structures that crayfish and grasshopper have in common, according to the orange sheet)1.Antenna: for sensing and feeding2.Compound eye: to see shape, color, movement, and tell the distance3.Walking legs: to walk on ground4.Stomach: to digest food5.Intestine: to absorb nutrients6.Anus: secrete solid waste7.Mouth: where food enters.

The following links may be helpful for the practical (crayfish/grasshopper); I suggest visiting all of them: