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Invertebrates
Earthworms are invertebrates. That is, they do not have a backbone. Insects, sea stars, Spiders, jellyfish, and millipedes are other examples of invertebrate animals.
Segments
Study the illustration of an earthworm shown below. You will notice that earthworms have long, cylindrical body that is divided into similar segments. The grooves that extend around the body of the worm show the arrangement of the segments.
Some species of earthworms have a body composed of over 100 segments. How many segments does your earthworm have?
Symmetry
Earthworms have bilateral symmetry. This means that if you cut the earthworm down the centerline, the left side of the body would be identical to the right side.
Body Colours
One of the key features of an earthworm is the colour of its body. Some species of earthworms have a dark-red or red-violet body while other species are muddy-green. However, there are species that do not have these colours. For the purposes ofWorm Watch, these animals are said to have "other body colours."
Prostomium
Some species of earthworms have a tongue-like lobe above the mouth called prostomium. The prostomium is actually a sensory device. Earthworms do not have a nose, eyes, ears, or hands to gather sensory information about their environment. Instead, they depend on their prostomium and sensory receptors in their skin to "feel" their way through the soil.
Peristomium
The first body segment is called theperistomium. The peristomium contains the mouth.
Clitellum
Adult (sexually mature) earthworms have a distinct swelling called a clitellum. It is located about one-third of the way down the earthworm. The clitellum is often white or orange in colour. It produces most of the material secreted to form earthworm cocoons. The clitellum forms a band that can be flared, non-flared, saddle-shaped, or annular. It is generally found between segments 26 and 33.
The clitellum is only found on adult worms. Young or juvenile worms do not have a clitellum. The clitellum of each species of earthworm has a distinct colour, size, and shape. Another key structure found on the clitellum is thetubercula pubertatis.
The diagram shows the shape and structure of the clitellum. They may have any combination of shapes.
Tubercula Pubertatis (TP)
The tubercula pubertatis (TP) is another structure used to identify earthworms. The TP are glandular swellings located on both sides of the clitellum. They can assume a variety of shapes such as long and narrow, triangular, or sucker-like.
The shape and location of the tubercula pubertatis (TP) on the clitellum are key features used to identify mature earthworms.]
Genital Tumescences (GT)
The genital tumescences (GT) are areas of modified epidermis (skin) that do not have distinct boundaries. These are openings through which follicles of genital setae open.
The pattern and location of the GT are important clues to identifying different species of earthworms.]
Anterior
Locate the clitellum of a mature earthworm. The shorter region to one side of the clitellum is the anterior or head-end of the animal. This end of the worm is usually more pointed than the posterior end of the animal.
The prostomium is the first segment at the anterior end of the animal.
Posterior
Locate the clitellum of a mature earthworm. The longer region is the posterior or tail end of the earthworm.
Dorsal
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.
Ventral
The bottom-side of an animal is called the ventralsurface. In many animals, the ventral surface is a lighter colour or shade than the dorsal surface.
Periproct
The periproct is the last segment of an earthworm.
Setae
Each segment, except the first and last, have tiny bristle-like structures called setae. These structures help the earthworm to move and act to sense the environment.
The number and arrangement of setae are important clues to the identification of earthworms.]
Epidermis
The epidermis is the name for the skin of an earthworm. It is the outer layer of worm and it secretes a mucous.
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Does earthworm has scales?
No. They have segments.
On what area of the earthworm body do these bristles appear?
The bristles along the body of an earthworm are called the Setae,which are set along its segmented length. In all the body segments except the first, last and clitellum, there is a ring of S-shaped setae embedded in the epidermal pit of each segment.
What is the function of the segments of an earthworm?
Opinion 1. It varies depending on the species, but each has at least 37 segments. http://animals.howstuffworks.com/worms/earthworm-info.htm Opinion 2. Thats wrong, worms have over 100 segments. (i vote for #1.)
How many body segments does a cylinder millipede have?
two single segments
What organ removes wastes from an earthworms blood?
Pair of nephridia in earthworm's segments excretes waste through pores in the skin, removing waste from the blood and body fluids.
What happen to the shape of the earthworm when the circular muscles contract?
When the circular muscles of an earthworm contract, the segments of its body become thinner and longer, causing the earthworm to elongate and appear stretched out.
How many segments are there in front of the clittelum?
There are 14 segments in front of the clitellum in an earthworm.
How many segments does a earthworm have?
An earthworm typically has around 100-120 segments. Each segment contains muscle fibers that help the earthworm move and burrow through soil.
The number of segments between prostomiun and clitellum?
There are about 30 segments between the prostomium and clitellum of an earthworm. actually this question asked as differently as "How many segments are between the prostomium and clitellum of an earthworm?" see answer for this question.
Does earthworm has scales?
No. They have segments.
What is The first segment of the earthworm?
Segments
How many segments does a worm have?
An earthworm, Annelida [= ringed] has up to five pairs of hearts.
How many nephridiopores are in each segment of the earthworm?
Except for the first and last segments, which have no setae, there are eight tiny bristle-like structures that can not be seen with the naked eye called setae on each segment of an earthworm. The arrangement of the setae is one factor that helps in the identification of earthworms, as they can be closely or widely paired in four pairs or separate. Setae grip the soil to help the earthworm move about and sense the enviroment.
How many segments of an earth worm have a heart?
An earthworm, Annelida [= ringed] has up to five pairs of hearts.
Function of septa in earthworm?
Septa in earthworms separate each segment of the body internally. They provide structural support and help in coordinating muscle movement for locomotion. Additionally, septa help in the circulation of fluids and gases within the body segments.
What helps an earthworm dig through the soil and where is this located?
An earthworm's ability to dig through soil is aided by its strong, muscular body and the hydraulic pressure created by its body fluids. The earthworm's setae, tiny bristle-like structures on its body, also help it grip onto soil particles as it moves. These structures are located along the earthworm's body segments.
Which segments lack nephridia?
Nervous system, respiratory system, and circulatory system lack nephridia.
