4.276: Earthworm and Grasshopper Locomotion

What happens when the posterior longitudinal muscle contracts in an earthworm?

• The earthworm becomes longer and thinner

• The earthworm becomes shorter and thicker

• The earthworm jumps forward

• The earthworm remains still

What do the chaetae at the posterior segment of an earthworm do?

• Release their hold of the ground

• Anchor to the ground

• Remain still

• Jump forward

Which muscles contract in the anterior segment of an earthworm?

• None of the above

• Longitudinal muscle

• Circular muscle

• Both circular and longitudinal muscles

What are the antagonistic muscles of a grasshopper attached to?

• Outer surface of the exoskeleton

• Wings

• Inner surface of the exoskeleton

• Leg joints

What does the flexor do in a grasshopper's hind leg?

• Contracts to pull the leg towards the body

• Straightens the leg backwards

• Remains still

• Anchors to the ground

What is the position of the hind leg when the flexor contracts in a grasshopper?

• Straightened backwards

• Folded into a Z shape

• Anchored to the ground

• Extended forward

What is the purpose of the extensor in a grasshopper's hind leg?

• Extends forward

• Anchors to the ground

• Straightens the leg backwards

• Pulls the leg towards the body

What happens when the chaetae at the anterior segment of an earthworm anchor to the ground?

• The earthworm jumps forward

• The earthworm becomes shorter and thicker

• The earthworm becomes longer and thinner

• The earthworm remains still

What is the function of the flexor and extensor in a grasshopper's hind leg?

• Bend and straighten the leg joint

• Anchor the leg to the ground

• Extend and retract the leg

• Rotate the leg

How are the hind legs of a grasshopper adapted for jumping/leaping?

• Muscular and long

• Short and weak

• Thin and fragile

• Stiff and short