1. Examine your earthworm and determine the dorsal and ventral sides. The ventral side appears flatter than the other side of the worm. The dorsal side is
the worm's rounded top
.
How do you find the dorsal side of an earthworm?
Locate the clitellum
How did you determine which side was the dorsal and ventral side of the earthworm?
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. Turn the worm ventral side up, as shown in the diagram below.
How can you tell the dorsal side from the ventral side?
The top-side of an animal is called the dorsal surface. For example, the fin you see in all shark movies shows the dorsal fin of a shark just before it attacks. The dorsal surface of some species of earthworms is darker than its ventral surface. The bottom-side of an animal is called the ventral surface.
How do you tell which side is the head of a worm?
The head of a worm is always located
on the end closest to the swollen band, called the clitellum
Why is the dorsal side of the earthworm darker?
The eartworm places its dorsal side up in the summer,
when the dirt is brown
. In winter, it flips its lighter ventral side up to blend in with the snow. D) The setae are lighter than the earthworm's skin and, therefore, make the ventral side look lighter. The dorsal side does not have setae.
How many hearts does a worm have?
Heartbeats: Worms don't have just one heart. They have
FIVE
! But their hearts and circulatory system aren't as complicated as ours — maybe because their blood doesn't have to go to so many body parts. Moving around: Worms have two kinds of muscles beneath their skin.
What is the white band on a worm?
Jumping worms have a milky-white to
gray clitellum
Does earthworm have a distinct head?
Worms have
a definite anterior (head) end
and a posterior (tail) end. The ventral surface of worms and other organisms is the bottom side of the body, often closest to the ground.
Do worms feel pain when cut in half?
But a team of Swedish researchers has uncovered evidence that
worms do indeed feel pain
, and that worms have developed a chemical system similar to that of human beings to protect themselves from it.
Do Earthworms make sounds?
They also make
a loud popping noise
that sounds like a champagne cork, underwater microphones revealed. Researchers say the popping sounds emitted by the worms are almost as loud as those of snapping shrimp, which produce sounds so powerful they can break small glass jars.
Do worms have genders?
Earthworms are
hermaphrodites
, meaning an individual worm has both male and female reproductive organs.
What muscles are necessary for the earthworm to move?
An earthworm moves using
circular and longitudinal muscles
, as well as bristles called setae. The earthworm can push the setae out of its body to grab the soil around it. To move forward, the worm uses its setae to anchor the front of its body and contracts the longitudinal muscles to shorten its body.
What does a gizzard do in an earthworm?
Gizzard. Earthworms do not have teeth, so they use the strong muscles of the gizzard (and grains of sand and soil)
to grind up their food
.
Where is the clitellum located in a worm?
About one third of the way down the earthworm (from the head)
is the clitellum (see figure 1). The clitellum is a swelling of the skin and can only be seen in earthworms that are ready to reproduce. It may be white, orange-red or reddish-brown in colour. Earthworms are ready to mate when their clitellum is orange.
