They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe. If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
The movements of the worm's body make the blood flow back to the back end of the body, and the hearts pump the blood forward again. Carbon dioxide dissolves out of the blood back to the skin. Eating : Worms do not have teeth, but their mouths are muscular and strong. Nightcrawlers can even pull leaves into their burrows using their strong mouths. The front end of the worm, its prostomium , is pointed and firm, making it easy for worms to push their way into crevices as they eat their way through their burrows.
The mouth of the worm is just behind the prostomium. Worms swallow pieces of dirt and decaying leaves, and the food passes through the pharynx , located in body segments , the esophagus segments , and into the crop, which stores food temporarily.
The worm's stomach is very muscular, so is called a gizzard. Like a bird's gizzard, it grinds up the food, which then moves into the intestine. The intestine extends over two-thirds of the worm's body length.
In the intestine, food is broken down into usable chemicals which are absorbed into the bloodstream. Leftover soil particles and undigested organic matter pass out of the worm through the rectum and anus in the form of castings , or worm poop.
Worm poop is dark, moist, soil-colored, and very rich in nutrients. That's why farmers and gardeners like to have lots of worms in their soil. Cleaning out the blood : Worms don't have kidneys, but they have something serving the same purpose. Earthworms sit in a taxonomic group called annelids, or segmented invertebrates. Other members include leeches, and other terrestrial and aquatic worms, some of which can grow to be 11 feet long. The world has more than 1, species of terrestrial worms that scientists largely consider earthworms, and they have spread far across the Earth.
The United States of America, for instance, has 17 native species and 13 species introduced from Europe. Earthworms can appear in almost any climate that has soil with enough decaying matter and moisture to sustain them. Earthworm bodies have an outer layer of muscle, epidermis skin and cuticle protective hard layer.
They have between and segments and a tube-like shape, which allows the species to easily move through soil. Its innards, as such, also arrange themselves within this cavity. An earthworm's "hearts" sit near the creature's mouth in five pairs, and function much like a human heart, though earthworms breathe oxygen through their skin and require moisture for respiration. These heart-like organs bear a resemblance to arches, hence the name aortic arch.
Some species of annelids regulate heartbeat using their muscles, while earthworms use nerve cells, much like vertebrates. In this way, an earthworm's hearts may seem more similar to a proper, human heart than other members of the annelid grouping. These juvenile worms then enter the host's lymphatic system and are distributed through the body via the circulatory system to active skeletal muscle into which they burrow and become enclosed in cysts.
This slide shows male and female dog hookworms Ancylostoma caninum. The male is easily recognized by its conspicuous copulatory bursa, an expanded posterior portion of the worm used for grasping the female during mating. Several species of hookworms infect over a billion people in warmer regions of the world, including the southeastern United States.
Juvenile parasites gain entrance their hosts often barefoot children by burrowing through the skin. Note the mouth with hook-like cutting teeth that are used to attach to the wall of the intestine where they feed on blood. Heavy infestations can cause anemia, malnutrition and retarded development. This slide shows a stained adult pinworm Enterobius vermicularis.
Although they can cause anal itching, they seldom constitute a serious health hazard because they feed on wastes and bacteria in the cecum and appendix of the large intestine.
This slide shows a close-up of the pharyngeal region of a stained adult pinworm Enterobius vermicularis. Note how the muscular pharynx on this specimen ends in an expanded pharyngeal bulb, which is a characteristic of nematodes in this group.
This slide shows a live freshwater nematode. Although some nematodes including those shown in the previous pages are parasitic, many species are free-living. Free-living forms may feed on small animals including other nematodes , plant material, algae and fungi. Many freshwater and marine nematodes are deposit-feeders that ingest substrate particles that contain dead or decaying organic matter.
This slide shows a number of living nematodes that are commonly referred to as "vinegar eels" Turbatrix aceti. These free-living roundworms exist by feeding on bacteria and fungi found in the sediments of nonpasteurized vinegar. When viewed alive, vinegar eels are seen to be in constant motion, using vigorous dorsolateral undulations to propel themselves through the medium. This slide shows a blood smear containing two microfilariae of the dog heartworm Dirofilaria immitis.
Infection by this parasite occurs when the larval heartworms are transferred to the definitive host through the bite of a mosquito, the nematode's intermediate host.
Heavy infestations of adult worms which live in the heart and large arteries of the lungs can be fatal. The regular use of heartworm medication obtained from a licensed veterinarian can prevent the disease. This image shows an actual dog's heart infected with adult heartworms Dirofilaria immitis. These nematode parasites which are transmitted by the bite of a mosquito carrying the microfilariae stage of the parasite are a major menace to the health of dogs in North America.
The use of heartworm pills can prevent this serious disease! The above image shows a magnified view of the anterior end of the large intestinal roundworm Ascaris lumbricoides , one of the largest of the parasitic roundworms, with females reaching a length of up to 30 cm in humans! The digestive system of nematodes consists of a mouth that leads to a muscular pharynx, from there to a long, non-muscular intestine 1 , which is injected with yellow latex on the dissection mount, a short rectum and terminal anus.
Since the intestine is only one cell layer thick and lacks any musculature, food must be moved posteriorly by body movements and by additional food being passed into the intestine from the muscular pharynx. The above image shows a magnified view of the middle portion of the large intestinal roundworm. Except for the thin, non-muscular intestine 1 , most of the internal organs are given over to reproduction. In females, a short vagina 2 leads from the genital pore to a point where it splits into two large uteri 3.
Each uterus continues to highly coiled oviducts 4 that eventually terminates in thread-like ovaries shown on the next page. The above image shows a magnified view of the terminal portion of the large intestinal roundworm. Note the highly coiled, thin ovaries 2 in which the eggs are produced. As the eggs mature, they move into the oviduct and from there they are carried to the two uteri one of which is shown on the image as structure number 1 where they are fertilized by ameboid sperm from a male worm.
A single female can produces thousands of eggs each day. These eggs which are deposited in the soil with the feces of their hosts can remain viable for months or even years. Not surprisingly, over a billion people on earth are infected with the large intestinal roundworm!
Also seen on the image is the end of the non-muscular intestine 3. Home Zoo-lab. Examples of polychaete worms include: Nereis virens the clamworm , Amphitrite the spaghetti worm , Glycera the beak thrower , Chaetopterus the parchment worm , Aphrodita the sea mouse and fan worms also called feather duster worms or Christmas tree worms Nereis virens Lab-7 01 Nereis virens is a common polychaete inhabitant of shallow waters along the Atlantic coast of North America.
Amphitrite Lab-7 02 Lab-7 03 Amphitrite is a genus marine polychaete worm that lives in the mucus tubes, which become thickly covered in fine sand and broken shell material. Glycera Lab-7 04 This marine polychaete is a voracious predator that remains hidden in an elaborate gallery system constructed in a muddy bottom.
Chaetopterus Lab-7 05 This unique polychaete lives in mud flats in a leathery, open-ended U-shaped tube. Aphrodita Lab-7 06 This strange looking polychaete has numerous felt like setae on the dorsal surface and parapodia on the ventral surface that allow it to crawl across the substrate. Dorsal surface Lab-7 09 This image of a sea mouse show the brilliantly colored setae that emerge from its scaled back.
Ventral surface Lab-7 11 This image shows the ventral surface of a sea mouse with its numerous parapodia that permit it to crawl over the substrate in search of prey. Fan worms Lab-7 07 These colorful polychaetes sometimes called feather duster worms or Christmas tree worms live in tubes constructed of sand grains embedded in mucus. Freshwater forms Lab-7 10 Although most oligochaetes are terrestrial, some live in freshwater. Reproduction Lab-7 12 During the reproduction, two earthworms come together from opposite directions in a way so that their clitella are in contact.
Phylum Annelida - Class Hirudinea Lab-7 13 The Class Hirudinea contains about species of leeches that have bodies that are flattened dorsoventrally and lack setae. Medical leech Lab-7 14 The medicinal leech Hirudo medicinalis is best known as the organism used for blood letting people used to believe many health problems caused by getting rid of "bad" blood. Phylum Nematoda Lab-7 15 Phylum Nematoda contains about 12, species of roundworms. Phylum Onychophora Lab-7 16 The Phylum Onychophora contains about 70 species of small, nocturnal, caterpillar-like animals called "velvet worms" or "walking worms" that live in rain forests and other tropical and semitropical leafy habitats of the Southern Hemisphere.
Nereis c. Lab-7 17 Dorsal blood vessel Longitudinal muscles Coelom Lumen of intestine Ventral nerve cord Ventral blood vessel Parapodia This slide shows a cross section through the body of a clamworm Nereis virens. Dorsal region close-up Lab-7 18 Dorsal blood vessel Longitudinal muscles Cuticle Hypodermis Circular muscle layer Ventral region close-up.
Earthworm c. Lab-7 20 Dorsal blood vessel Body wall layers Nephridium Seta Ventral blood vessel Ventral nerve cord Typhlosole Intestinal lumen Coelom This slide shows a stained cross section through the body of a common earthworm Lumbricus terrestris. Earthworm body wall layers close-up Lab-7 21 Cuticle Hypodermis Circular muscles Longitudinal muscles Earthworm setae close-up. Leech w. Lab-7 25 This slide shows a stained whole mount of a common freshwater leech Helobdella stagnalis with its proboscis extended.
Earthworm setae Lab-7 31 This slide shows a another cross section through the body of a common earthworm Lumbricus terrestris. Earthworm nephridium Lab-7 33 Nephridia Nephridiopore Coelom Intestinal lumen This slide shows a cross section of the common earthworm Lumbricus terrestris. Earthworm nephridiopore close-up Lab-7 34 Nephridiopore Hypodermis Circular muscle layer Longitudinal muscles.
Earthworm dissection mount 1 anterior region Lab-7 35 Pharynx Esophagus Aortic arch Seminal receptacle Seminal vesicle Crop Gizzard Intestine This image shows the anterior region of a preserved earthworm.
Earthworm dissection mount 2 anterior region Lab-7 36 Intestine Ventral nerve cord Dorsal blood vessel This image shows the middle region of a preserved earthworm. Earthworm model Lab-7 37 This image and the three close-up views linked above is taken from a plastic model of an earthworm.
Segments Lab-7 38 1. Segments Lab-7 39 1. Seminal vesicles Segments Lab-7 40 1. Earthworm dissection Lab-7 41 This dissection of a preserved earthworm shows some of the more conspicuous features of its internal anatomy. Ascaris lumbricoides male c. Lab-7 42 Cuticle and hypodermis Longitudinal muscle layer Vas deferens Testis Lateral line with excretory canal Intestine Pseudocoelom This slide shows a cross section of a stained, male, large intestinal roundworm Ascaris lumbricoides.
Ascaris lumbricoides female c. Lab-7 44 Cuticle and hypodermis Longitudinal muscle layer Ovary Oviduct Uterus Intestine This slide shows a cross section of a female, large intestinal roundworm Ascaris lumbricoides. Trichinella spiralis infected muscle section Lab-7 46 Encysted larvae Skeletal muscle fibers This slide shows a section of skeletal muscle the containing encysted larvae of the nematode parasite Trichinella spiralis.
Ancylostoma caninum male and female w. Ancylostoma caninum close-up Lab-7 48 cutting tooth. Enterobius vermicularis w. Close-up view of the pharyngeal region Lab-7 50 Mouth Pharynx Pharyngeal bulb This slide shows a close-up of the pharyngeal region of a stained adult pinworm Enterobius vermicularis. Freshwater nematode Lab-7 51 This slide shows a live freshwater nematode.
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