How do you prepare a worm for dissection?
Put the worm in a bowl of 50% alcohol. Without that, the worm will most likely be stiff and contracted, making for a harder time dissecting. If the worm is already dead, make sure the body is still soft and flexible. Immediately place it in alcohol to preserve the body.
What side of the worm should be facing up for a dissection?
dorsal side
Lay the worm on your dissecting tray with its dorsal side facing up. Use dissection pins to secure each end on the tray. Start your dissection about an inch posterior to the clitellum. Lift up the skin with a pair of forceps and snip an opening with a pair of dissecting scissors.
What is the purpose of dissecting a worm?
Purpose: In this lab, you will dissect an earthworm in order to observe the external and internal structures of earthworm anatomy, whilst following the all-important lab safety procedures.
How do you Disect a worm?
Place the earthworm on its ventral side. (The ventral side is more flattened than the dorsal side.) Using dissecting scissors, cut through the dorsal body wall posterior to the clitellum and continue the incision toward the prostomium. Be careful not to cut too deep or you will slice into the digestive system.
What is the purpose of the clitellum?
animal reproduction Sexually mature oligochaetes have a clitellum, which is a modification of a section of the body wall consisting of a glandular, saddlelike thickening near the gonopores. During copulation, the clitellum secretes a mucus that keeps the worms paired while sperm are being exchanged.
How do you know which side of the worm is dorsal and which is ventral?
Gather your lab materials. 2. Place the earthworm in the dissecting tray. Identify the dorsal side, which is the worm’s rounded top, and the ventral side, which is its flattened bottom.
Is the circulatory in the worm open or closed?
closed circulatory system
The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels. There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels.
How many pieces can you cut a flatworm into?
Planarians certainly excel at it, though; a flatworm can recover from being cut up into a staggering 279 tiny pieces, each of which regenerates into a new worm!
Can a worm split in two?
If an earthworm is split in two, it will not become two new worms. The head of the worm may survive and regenerate its tail if the animal is cut behind the clitellum. But the original tail of the worm will not be able to grow a new head (or the rest of its vital organs), and will instead die.
What do setae do?
Bristles, called setae, are located on each segment of the earthworm’s body. They prevent the earthworm from slipping backwards. FEEDING The earthworm is specially adapted for feeding underground. passes out of the body through the anus.
Where are the seminal receptacles located?
Seminal vesicles are also called seminal glands or vesicular glands. They are sacs about 2 inches long that are located behind your bladder but in front of your rectum.