Were You Previously Informed?
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Were You Previously Informed?
Earthworms are an integral part of the earth! They eat the soil, and then they fertilize it and make it nice and rich over time, making mediocre farmland into farmland people will sell their souls for! Without Earthworms, most of the soil in the world would be somewhat infertile. Thank the Lord for the Earthworms!
Were You Previously Informed?
The largest earthworm ever found was in South Africa and measured 22 feet from its nose to the tip of its tail!
Were You Previously Informed?
Earthworms are enjoyed raw by children, cooked and fried by adults, and cause no parasitic infections, contrary to popular belief. Also, fear of worms is scoleciphobia or vemiphobia.
Tuesday, March 6, 2007
Excretion
-Annelids produce two kinds of waste, solid and metabolism wastes.
-The solid wastes are excreted by anus.
-The wastes that come from metabolism are excreted by nephridia.
-A pair of nephridia in each of the septa excretes the wastes out of the body to the outside.
Example (Earthworms):
-The excretory system in earthworms consists of a pair of nephridia for each segment.
-Each nephridia consists of a long, convoluted tubule that begins with a ciliated funnel.
-Fluid is carried into the funnel by the beating of the cilia and is excreted through an outer pore.
-The solid wastes are excreted by anus.
-The wastes that come from metabolism are excreted by nephridia.
-A pair of nephridia in each of the septa excretes the wastes out of the body to the outside.
Example (Earthworms):
-The excretory system in earthworms consists of a pair of nephridia for each segment.
-Each nephridia consists of a long, convoluted tubule that begins with a ciliated funnel.
-Fluid is carried into the funnel by the beating of the cilia and is excreted through an outer pore.
Feeding
-Some annelids feed on a wide variety of organic matter, primarily detritus and algae.
-They are considered to be beneficial animals because they eat when moving through the ground.
-When the annelid eats the food, the extra it doesn't need is excreted in the form of castings.
-These casting are high in nutrients and are then used for food for other animals.
-Because the annelids burrow into the ground to eat, the rain water seeps deeper into the ground to help get more water to the plants.
-Some annelids are sanguivorous, that is they feed as blood sucking parasites on preferred hosts.
-If they cant find the preferred hosts, they will find another suitable host to feed on.
-Some feed on humans and other mammals, but some feed on fish, frogs,turtles, etc...
-Some even feed on other sanguivorous annelids.
-The annelid can ingest a large quantity of blood, which it then goes into a dark spot to digest it. The digestion is slow, and lets the annelid survive a long time without feeding.
-They are considered to be beneficial animals because they eat when moving through the ground.
-When the annelid eats the food, the extra it doesn't need is excreted in the form of castings.
-These casting are high in nutrients and are then used for food for other animals.
-Because the annelids burrow into the ground to eat, the rain water seeps deeper into the ground to help get more water to the plants.
-Some annelids are sanguivorous, that is they feed as blood sucking parasites on preferred hosts.
-If they cant find the preferred hosts, they will find another suitable host to feed on.
-Some feed on humans and other mammals, but some feed on fish, frogs,turtles, etc...
-Some even feed on other sanguivorous annelids.
-The annelid can ingest a large quantity of blood, which it then goes into a dark spot to digest it. The digestion is slow, and lets the annelid survive a long time without feeding.
Habitat and adaptations
Earthworms
-Earthworms are found in many terrestrial environments ranging from semi-arid habitats to moist, well-vegetated areas.
-Some earthworms are found in wetter areas, or they can be found in soil, under logs, and usually come out of the soil after a heavy rain because it is becoming water-logged
Leeches:
-Most leeches are freshwater animals, but many terrestrial and marine species occur.
-Land leeches are common on the ground or in low foliage in wet rain forests. In drier forests they may be found on the ground in seepage moistened places. Most do not enter water and cannot swim, but can survive periods of immersion.
-Some species burrow in the soil where they can survive for many months even in a total lack of environmental water.
-Earthworms are found in many terrestrial environments ranging from semi-arid habitats to moist, well-vegetated areas.
-Some earthworms are found in wetter areas, or they can be found in soil, under logs, and usually come out of the soil after a heavy rain because it is becoming water-logged
Leeches:
-Most leeches are freshwater animals, but many terrestrial and marine species occur.
-Land leeches are common on the ground or in low foliage in wet rain forests. In drier forests they may be found on the ground in seepage moistened places. Most do not enter water and cannot swim, but can survive periods of immersion.
-Some species burrow in the soil where they can survive for many months even in a total lack of environmental water.
Monday, March 5, 2007
Reproduction
-Depending on the species, annelids can reproduce sexually or asexually.
Asexual:
-fission is a method used by some annelids and allows them to reproduce quickly.
-the posterior end of the annelid breaks off and forms into a new worm.
Lumbriculus and Aulophorus (different kinds of annelids) for example, are known to reproduce by the body breaking into such fragments.
Sexual:
-Some annelida species are hermaphroditic, while others have distinct sexes.
-Most annelida reproduce by copulation.
-Two worms which are attracted by each other's secretions lay their bodies together with their heads pointing opposite directions. The fluid is transferred from the male pore to the other worm.
-Some annelida transfer sperm differently, by means of using a spermathecae (sperm storing chambers)
-The clitellum secretes a muscus that makes a 'coocon' around the egg and start to develop.
Asexual:
-fission is a method used by some annelids and allows them to reproduce quickly.
-the posterior end of the annelid breaks off and forms into a new worm.
Lumbriculus and Aulophorus (different kinds of annelids) for example, are known to reproduce by the body breaking into such fragments.
Sexual:
-Some annelida species are hermaphroditic, while others have distinct sexes.
-Most annelida reproduce by copulation.
-Two worms which are attracted by each other's secretions lay their bodies together with their heads pointing opposite directions. The fluid is transferred from the male pore to the other worm.
-Some annelida transfer sperm differently, by means of using a spermathecae (sperm storing chambers)
-The clitellum secretes a muscus that makes a 'coocon' around the egg and start to develop.
General Characteristics
Annelids are triploblastic protosomes that have a complete coelom. They have a closed circulatory system (blood is contained inside blood vessels) and are segmented. The segmentations are called Septa.
Oligochaetes and Polychaetes typically have spacious coeloms, but in leeches, the coelom is filled in with tissue and reduced to a system of narrow canals.
Typically, each compartment corresponds to a single segment of the body, which also includes a portion of the nervous and circulatory systems, allowing it to function somewhat independently. This means that if part of it is cut off, it can still function without the other half since it has the nessecary parts in each segment!
Each segment is marked externally by something called an Annuli. Annelids have a wide variety of diets, including active and passive hunters, scavengers, filter feeders, deposit feeders, and blood-suckers. Annelids have two main blood vessel; dorsal and ventral blood vessel.
Oligochaetes and Polychaetes typically have spacious coeloms, but in leeches, the coelom is filled in with tissue and reduced to a system of narrow canals.
Typically, each compartment corresponds to a single segment of the body, which also includes a portion of the nervous and circulatory systems, allowing it to function somewhat independently. This means that if part of it is cut off, it can still function without the other half since it has the nessecary parts in each segment!
Each segment is marked externally by something called an Annuli. Annelids have a wide variety of diets, including active and passive hunters, scavengers, filter feeders, deposit feeders, and blood-suckers. Annelids have two main blood vessel; dorsal and ventral blood vessel.
Sources
-Biology by Miller Levine book
-http://www.biology.iastate.edu/Courses/201L/Annelida/%20AnnelINDX.htm
-http://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/Annelida.html
-http://www.kn.att.com/wired/fil/pages/listannelidama.html
-http://www.blobs.org/science/diffusion/imgs/diffusion2.gif
-http://sps.k12.ar.us/massengale/unsegmented_worm_notes_b1.htm
-http://infusion.allconet.org/webquest/annelida.html
-http://www.amonline.net.au/factsheets/leeches.htm
-http://www.ento.csiro.au/education/allies/annelida.html
-http://tolweb.org/Annelida
-http://www.biology.iastate.edu/Courses/201L/Annelida/%20AnnelINDX.htm
-http://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/Annelida.html
-http://www.kn.att.com/wired/fil/pages/listannelidama.html
-http://www.blobs.org/science/diffusion/imgs/diffusion2.gif
-http://sps.k12.ar.us/massengale/unsegmented_worm_notes_b1.htm
-http://infusion.allconet.org/webquest/annelida.html
-http://www.amonline.net.au/factsheets/leeches.htm
-http://www.ento.csiro.au/education/allies/annelida.html
-http://tolweb.org/Annelida
Vocabulary
Annelid: round tubular animal that has a long segmented body. Belongs to phylum Annelida. Triploblastic.
Polychaetes: literally meaning "many-bristled", they are segmented worms (usually aquatic) characterized by laterally paired appendages on its body segments and a "spiky" body.
Oligochaeta: Annelid worm. The class that contains the common earthworm and related species that live in soil and in water. Literally means, "few-bristled".
Leech: Annelid worm. Typically exists as an external parasite that drinks the blood and body fluids of its host. Hooks on using mouth, and can drink up to 10x their weight.
Longitudinal muscles: Runs from the anterior of the worm to the posterior. When these muscle contract they make the worm shorter.
Circular Muscles: Muscles that run throughout the worm like a coil. When contraction occurs, worm elongates.
Septa: Plural of Septum. means, "Something that encloses." A wall separating the segments in an Annelid.
Nephridia: Plural of Nephridium. the excretory organ of many invertebrates, consisting of a tubule with one end opening into the body cavity and the other opening into a pore at the body surface.
Sanguivorous: Literally means, "that which eats blood" or something to that effect. Means blood-feeding, or blood eating.
Lumbriculus: A division of Oligochaeta
Aulophorus: A division of Oligochaeta
Hermaphroditic: An organism with both male and female reproductive organs.
Copulation: Sexual Intercourse.
Spermathecae: a small sac or cavity in hermaphroditic invertebrates used to store sperm for fertilizing eggs, such as in earthworms.
Clitellum: It secretes a mucus ring into which egg and sperm are released.
Pharynx: muscular front end of the digestive tube which can be extend to get food.
Triploblastic: Having three germ layers.
Coelom: A body cavity completely surrounded by mesoderm.
Annuli: In this case (earthworms), a ring mark.
Trochozoa: Full name is Lophotrochozoa; one of 3 major groups of protosome animal.
Polychaetes: literally meaning "many-bristled", they are segmented worms (usually aquatic) characterized by laterally paired appendages on its body segments and a "spiky" body.
Oligochaeta: Annelid worm. The class that contains the common earthworm and related species that live in soil and in water. Literally means, "few-bristled".
Leech: Annelid worm. Typically exists as an external parasite that drinks the blood and body fluids of its host. Hooks on using mouth, and can drink up to 10x their weight.
Longitudinal muscles: Runs from the anterior of the worm to the posterior. When these muscle contract they make the worm shorter.
Circular Muscles: Muscles that run throughout the worm like a coil. When contraction occurs, worm elongates.
Septa: Plural of Septum. means, "Something that encloses." A wall separating the segments in an Annelid.
Nephridia: Plural of Nephridium. the excretory organ of many invertebrates, consisting of a tubule with one end opening into the body cavity and the other opening into a pore at the body surface.
Sanguivorous: Literally means, "that which eats blood" or something to that effect. Means blood-feeding, or blood eating.
Lumbriculus: A division of Oligochaeta
Aulophorus: A division of Oligochaeta
Hermaphroditic: An organism with both male and female reproductive organs.
Copulation: Sexual Intercourse.
Spermathecae: a small sac or cavity in hermaphroditic invertebrates used to store sperm for fertilizing eggs, such as in earthworms.
Clitellum: It secretes a mucus ring into which egg and sperm are released.
Pharynx: muscular front end of the digestive tube which can be extend to get food.
Triploblastic: Having three germ layers.
Coelom: A body cavity completely surrounded by mesoderm.
Annuli: In this case (earthworms), a ring mark.
Trochozoa: Full name is Lophotrochozoa; one of 3 major groups of protosome animal.
Circulation/internal transport.
-Because of the flatworm’s shape they don’t have a circulatory or respiratory systems.
-Flatworms use diffusion to transport oxygen and nutrients throughout their body
-ex in an earthworm the circulation system is in a series of closed vessels, the two main vessels are the dorsal and ventral blood vessels. In the dorsal vessel the blood moves towards the anterior and in the dorsal vessel the blood moves towards the posterior.
-Flatworms use diffusion to transport oxygen and nutrients throughout their body
-ex in an earthworm the circulation system is in a series of closed vessels, the two main vessels are the dorsal and ventral blood vessels. In the dorsal vessel the blood moves towards the anterior and in the dorsal vessel the blood moves towards the posterior.
Relations to Other Phyla
Annelids have several relations to other phyla, such as the Arthropods and the Molluscs.
Arthropods are considered the closest relatives of the Annelids, due to their similar/common segmented body structures, but seem quite different otherwise. It is assumed that they undrwent convergent evolution to create the grouping of Articula. The only differences between them are that Arthropods have an open circulatory system, a respiratory system (with a trachea, gills or book lung), excretory glands, normally sexual activity, and an exoskeleton.
Molluscs share with the Annelids the trocophore larvae stage, as it is present in both groups. It's due to this that the Annelids and the Molluscs are grouped together as the Trochozoa. The Molluscs and the Annelids are different only in the fact that the Molluscs have an open circulatory system, a respiratory system, have a well developed brain, and have a nerve network in their body walls.
Arthropods are considered the closest relatives of the Annelids, due to their similar/common segmented body structures, but seem quite different otherwise. It is assumed that they undrwent convergent evolution to create the grouping of Articula. The only differences between them are that Arthropods have an open circulatory system, a respiratory system (with a trachea, gills or book lung), excretory glands, normally sexual activity, and an exoskeleton.
Molluscs share with the Annelids the trocophore larvae stage, as it is present in both groups. It's due to this that the Annelids and the Molluscs are grouped together as the Trochozoa. The Molluscs and the Annelids are different only in the fact that the Molluscs have an open circulatory system, a respiratory system, have a well developed brain, and have a nerve network in their body walls.
Advantages and Disadvantages (of Movement)
The disadvantage of this sort of movement is that on land and in water, the annelids are very slow. So slow that the ones on land are preyed upon often, and thus spend most of their time underground, only popping up occasionally. The ones in the water are slightly better off, as they can move a bit faster, but still spend most of their time hiding or burrowed in the ground.
An advantage is that this sort of movement allows for them to eat while they move, a trait that must come in handy. For example, the earthworm must ingest the soil as moves through the soil, otherwise it can not make much headway. The earthworm then poops it out, and in that process, made the soil richer and more fertile. Without this need, the earth would be pretty barren, as earthworms help the soil become more rich wherever they go.
An advantage is that this sort of movement allows for them to eat while they move, a trait that must come in handy. For example, the earthworm must ingest the soil as moves through the soil, otherwise it can not make much headway. The earthworm then poops it out, and in that process, made the soil richer and more fertile. Without this need, the earth would be pretty barren, as earthworms help the soil become more rich wherever they go.
Digestion
Phylum Annelida: Digestion
The digestive system of annelids consists of an unsegmented gut that runs through the middle of the body from the mouth, located on the underside of the head then to the anus. The gut is separated from the body wall by the body cavity, called the coelom. The segmented compartments of the coelom are usually separated from each other by tissue, called septa, which are separated by the gut and by blood vessels. Except in the leeches, the coelom is fluid filled and functions as a skeleton, providing the animal with rigidity necessary for muscular movement.
The digestive system of annelids consists of an unsegmented gut that runs through the middle of the body from the mouth, located on the underside of the head then to the anus. The gut is separated from the body wall by the body cavity, called the coelom. The segmented compartments of the coelom are usually separated from each other by tissue, called septa, which are separated by the gut and by blood vessels. Except in the leeches, the coelom is fluid filled and functions as a skeleton, providing the animal with rigidity necessary for muscular movement.
Movement; Motile or Sessile?
As one with a working brain may assume, the Annelids are motile.
Annelids move by using the two (major) sets of muscles they have. The set of muscles that run from the anterior of the worm to the posterior are called longitudinal muscles, while the other set (circular) is set like a coil on the inside of the worm.
When the longitudinal muscles contract, they make the worm shorter, and when the circular set conracts, the annelid elongates. Aquatic annelids (most Polychaetes) make use of this to slowly make their way through the water, while underground annelids force through moist soil with this method of movement.
Polychaetae and Oligochaetae also move through the use of their Chaetae (sing. Chaeta). It has also been named Seta(e), but Chaeta applies to annelids specifically. Chaetae are bristle-like organic structures that are found on the topmost layer of skin. They are withdrawn when the body is extending, and allow for the Poly/Oligochaetae to have a better form of grip on the surface they are on, though Oligochaetae use this particular function more often.
Anyone else think these Chaetae look like crab legs?
Polychaetae have Parapodia, laterally paired appendages mainly used for creating currents, swimming and digging.
Annelids move by using the two (major) sets of muscles they have. The set of muscles that run from the anterior of the worm to the posterior are called longitudinal muscles, while the other set (circular) is set like a coil on the inside of the worm.
When the longitudinal muscles contract, they make the worm shorter, and when the circular set conracts, the annelid elongates. Aquatic annelids (most Polychaetes) make use of this to slowly make their way through the water, while underground annelids force through moist soil with this method of movement.
Polychaetae and Oligochaetae also move through the use of their Chaetae (sing. Chaeta). It has also been named Seta(e), but Chaeta applies to annelids specifically. Chaetae are bristle-like organic structures that are found on the topmost layer of skin. They are withdrawn when the body is extending, and allow for the Poly/Oligochaetae to have a better form of grip on the surface they are on, though Oligochaetae use this particular function more often.
Anyone else think these Chaetae look like crab legs?Polychaetae have Parapodia, laterally paired appendages mainly used for creating currents, swimming and digging.
Parapodia~!
Respiration
Phylum Annelida: Respiration
Aquatic Annelids mostly breathe through gills. Some of these aquatic annelids have brightly coloured gills that protrude from the opening from the worms burrow. Other annelids have small delicate gills along side of their body. Tube dwelling annelids breathe by fanning water though their burrows. The oxygen in the water is taken into the water and carbon dioxide is breathed out. Because of the aquatic annelids having this exchange of oxygen and carbon dioxide, it is essential that these gills are kept moist. If the gills are not kept moist the annelids will eventually die because it cannot respire.
General Anatomy
Phylum Annelida: General Anatomy
Annelids, or also known as segmented worms, are constructed by way of a tube within a body tube (Annelids have a complete gut. They have a mouth and an anus). This digestive tract runs through the center of the body. Segmented worms are known for being segmented externally as well as internally. The internal walls that separate the parts of the annelid are called septa (singular: septum). Most of these septa are similar but, there is a varying degree of similarity because some septa are needed to preform specialized tasks. For example, the first segments may carry one or more pairs of eyes and another one will be specialized other sense organs.
Annelids, or also known as segmented worms, are constructed by way of a tube within a body tube (Annelids have a complete gut. They have a mouth and an anus). This digestive tract runs through the center of the body. Segmented worms are known for being segmented externally as well as internally. The internal walls that separate the parts of the annelid are called septa (singular: septum). Most of these septa are similar but, there is a varying degree of similarity because some septa are needed to preform specialized tasks. For example, the first segments may carry one or more pairs of eyes and another one will be specialized other sense organs.
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