Annelida

__ Annelida __  **//Pookie McGlothern, Hannah Callison, and Brandon Peterson //**

**//The Annelida phylum is a phylum within the Animal Kingdom. //**  - Hirudinea (Leech) have segmented bodies, and no repiratory systems.
 * //Kingdom //****//: //** Animalia
 * //Phylum: //** Annelida
 * //Class: //** - Oligochaeta (earthworms) have segemented bodies, no repiratory system, and a ventral nerve cord[6].

-Earthworms (Nighcrawlers) -Leeches -Freshwater worms -Terrestrial worms -Blood worms -Antennae
 * //Annelida Phylum Animals: //**

T he animals in the <span style="font-family: 'Times New Roman',serif; font-size: 12pt;">Annelida <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">phylum are mostly marine worms, leeches, and freshwater and terrestrial worms [1]. Some names for these animals are the Nereis which is the clamworm, Hirudo which is a leech, and Lumbricus which are earthworms[11]. Other species are Bloodworms, Nightcrawlers, Leeches, Antennae, and other various segmented worms. There are many characteristics for the species in the Annelida phylum.

<span style="color: #002060; font-family: 'Times New Roman',serif; font-size: 12pt;">-Bilaterally Symmetrical -Closed circulatory system -Hydrostatic skeletons -Sectioned bodies -No real respiratory system -Hermaphrodites
 * //<span style="color: black; font-family: 'Times New Roman',serif; font-size: 16pt;">Symmetry and Characteristics //**

<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">There are four types of symmetry. There is **<span style="color: #002060; font-family: 'Times New Roman',serif; font-size: 12pt;">no symmetry **<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">, **<span style="color: #002060; font-family: 'Times New Roman',serif; font-size: 12pt;">bilaterial symmetry **<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">, **<span style="color: #002060; font-family: 'Times New Roman',serif; font-size: 12pt;">radial symmetry **<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">, and **<span style="color: #002060; font-family: 'Times New Roman',serif; font-size: 12pt;">pentaradial symmetry **<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">. No symmetry is the symmetry when the organism cannot be cut any way and have the sides line up. No two parts of the organism is the same. And example of an organism that does not have symmetry would be a sea sponge. They have so many different arms, that if you were to cut it a million different ways, still the halves would not be the same. Another type of symmetry is radial symmetry[12]. Radial symmetry is when an organism can be cut from the top, or the circular part, and still it would be the same on both halves. For an organism with radial symmetry such as the sea jelly, you can cut it a million different ways, and it will still be symmetrical. Another type of symmetry is pentaradial symmetry[17]. This one is sort of like the radial symmetry, but with limitations. Organisms such as the sea star can only be cut five different ways and still have symmetry. This is because organisms like the sea star have 5 “arms” and because of this, it can only be cut 5 ways before it loses its symmetry. The last type of symmetry is bilateral symmetry, and that is what Annelidas are. Annelida are bilaterally symmetrical and vermiform which means that you can cut them into two and both of the sides will look the same and vermiform means that they resemble or have the form of a worm[17]. The Annelid Phylum species also have a closed circulatory which means that the blood in their bodies just stays in the veins and arteries and capillaries ect[5]. The rest of the cells never come in direct contact with the blood[16]. The important stuff that the cells need for example oxygen still can travel to the cells because it is able to travel through the capillaries and reach the cells. The Annelids also have hydrostatic skeletons[3]. “Answer.com” states that hydrostatic skeletons are a “bone” structure found in most cold blooded and soft bodied animals. It is a fluid filled cavity surrounded by muscles this makes it easier from earthworms to burrow through the earth. On the website “Eartlife.net” <span style="font-family: 'Times New Roman',serif; font-size: 12pt;">in the Phylum Annelida article it says a <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">nother characteristic is that the species in the Annelida phylum their bodies possess three sections, a prostomium, a trunk and a pygidium. A prostomium, is the first body segment on annelid worms. It does not include the mouth, but acts as sort of an over lip when the animal is feeding[10]. The prostomium sometimes has antennae or eyes. On <span style="font-family: 'Times New Roman',serif; font-size: 12pt;"> “Dictionary.com” is says that t <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">he pygidium is the terminal section or the end of the body[14]. There is also another characteristic of annelids. It is that they are hermaphrodites <span style="font-family: 'Times New Roman',serif; font-size: 12pt;">. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;"> Hermaphrodites are organisms that have the sexual reproduction organs that a male and female should have separately. What this means is that the worm, has a male sexual reproduction parts, and it also has female sexual reproduction parts. Another characteristic of the Annelids are that they have no real respiratory system. Earthworms and other species in the Phylum Annelida don’t have lungs[17]. Organisms in the phylum Annelida breathe through their skin. The oxygen and carbon dioxide pass throughout the worm by diffusion. According to “Dictionary.com”diffusion is the movement of atoms or molecules from an area of higher concentration to an area of lower concentration. Atoms and small molecules can move from across the cell membrane by diffusion[10]. For this process to occur the worm’s body and skin must remain moist. Body fluids and mucous are released from the body to keep the worm moist so the need to be in damp soil. Even though worms are blind they are able to sense light. This is because the earthworm’s head is sensitive to the light.This is why earth worms and other worms usually come out at night also because the evaporating potential is low.

<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">Acoelomates are organisms that do not possess a body cavity. A body cavity is a fluid filled space in a multicelluar organism[9]. Organisms that do not gave a body cavity include sea jellys. Pseudcoelomates are organisms that possess “fake” body cavity. Organisms that have a “fake” body cavity and are Pseudcoelomates are round worms. The Phylum Annelida is coelomates. As stated in the definition on <span style="font-family: 'Times New Roman',serif; font-size: 12pt;">“Dictionary.com” coelomates <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">are animals who have a coelom. A coelom, as stated by <span style="font-family: 'Times New Roman',serif; font-size: 12pt;"> “Dictionary.com”, <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;"> is the body cavity in metazoans, located between the intestinal canal and body wall. The metazoans is a multicellular animal having cells differentiated into tissues and organs. This is usually a digestive cavity and nervous system. A metazoan animal is also any animal that undergoes development from an embryo stage with three tissue layers[8].
 * //<span style="font-family: 'Times New Roman',serif; font-size: 16pt;">Acoelomates, Pseudcoelomates, and Coelomates //**

<span style="color: #7030a0; font-family: 'Times New Roman',serif; font-size: 12pt;">-Cellular -Tissue -Organ
 * //<span style="color: black; font-family: 'Times New Roman',serif; font-size: 16pt;">Levels of Organization //**

<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">Cellular organization is the organization where the organisms are just a whole bunch of cells. An example of a type of organism that has cellular organization is a sponge. Tissue organization is when the tissues and cells are working together but they aren’t organs yet[4]. Organ organization is when the organism has organs that help it too function such as lungs, heart, liver, etc. The phyla Annelida have the level of organ organization since they possess organs.

<span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt;">The Phylum Annelida had become evolutionarily successful because of their characteristics. One main reason is because they are hermaphrodites. They have both male and female reproduction systems which allows for the birth rate to increase/remain steady [8]. Another is the hydrostatic skeleton that they possess. Without it, they would not be able to move through dirt and ground, leaving them vulnerable to predators. They have proved to be evolutionarily successful because they are still alive today.
 * //<span style="color: black; font-family: 'Times New Roman',serif; font-size: 16pt;">Evolutionary Success //**

<span style="display: block; font-family: 'Times New Roman',serif; font-size: 10pt; text-align: center;">Works Cited
 * 1) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"ADW: Hirudinea: Pictures" //Animal Diversity Web//. N.p., n.d. Web. 23 May 2011. <http://animaldiversity.ummz.umich.edu/site/accounts/pictures/Hirudinea.html>.
 * 2) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Annelida: Class Hirudinea Infoplease.com." //Infoplease: Encyclopedia, Almanac, Atlas, Biographies, Dictionary, Thesaurus. Free online reference, research & homework help. Infoplease.com//. N.p., n.d. Web. 23 May 2011. <http://www.infoplease.com/ce6/sci/A0856627.html>.
 * 3) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Answers.com - What is a hydrostatic skeleton." //WikiAnswers - The Q&A wiki//. N.p., n.d. Web. 23 May 2011. <http://wiki.answers.com/Q/What_is_a_hydrostatic_skeleton>.
 * 4) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Characteristics of Annelida." //NCWC: Student Pages//. N.p., n.d. Web. 23 May 2011. <http://students.ncwc.edu/bio101/invertebrates/characteristics_of_annelida.htm>.
 * 5) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Characteristics of Annelida." //Tree of Life Web Project//. N.p., n.d. Web. 23 May 2011. <http://tolweb.org/accessory/Characteristics_of_Annelida?acc_id=57>.
 * 6) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Class Oligochaeta." //Freshwater Benthic Ecology and Aquatic Entomology Homepage//. Chebucto Community Net, n.d. Web. 23 May 2011. <www.chebucto.ns.ca/ccn/info/Science/SWCS/ZOOBENTH/BENTHOS/xxv.html>.
 * 7) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Class: Polychaeta Nudibranch Species List for Identification Nudi Pixel." //Nudi Pixel: Nudibranch and Sea Slug Identification with Photographs//. N.p., n.d. Web. 23 May 2011. <http://www.nudipixel.net/class/polychaeta/>.
 * 8) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Coelom." //Dictionary.com//. Dictionary.com, n.d. Web. 23 May 2011. <dictionary.reference.com/browse/coelom>.
 * 9) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Coelomate." //Dictionary.com//. Dictionary.com, n.d. Web. 23 May 2011. <dictionary.reference.com/browse/coelomate>.
 * 10) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Diffusion." //Dictionary.com//. Dictionary.com, n.d. Web. 23 May 2011. <dictionary.reference.com/browse/diffusion>.
 * 11) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Earthworms." //School of Arts & Sciences - University of Pennsylvania//. N.p., n.d. Web. 23 May 2011. <http://www.sas.upenn.edu/~rlenet/Earthworms.html>.
 * 12) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">Myers, Phil. "ADW: Polychaeta: Information." //Animal Diversity Web//. N.p., n.d. Web. 23 May 2011. <http://animaldiversity.ummz.umich.edu/site/accounts/information/Polychaeta.html>.
 * 13) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Overview of the animal kingdom |www.bumlebee.org." //www.bumblebee.org Home Page//. N.p., n.d. Web. 23 May 2011. <http://www.bumblebee.org/invertebrates/Animalia.htm>.
 * 14) <span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Phylum Annelida." //Kingdom Animalia//. ESU, n.d. Web. 23 May 2011. <www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/Annelida.html>.__
 * 15) __<span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Pygidium." //Dictionary.com//. Dictionary.com, n.d. Web. 23 May 2011. <dictionary.reference.com/browse/pygidium>. __
 * 16) __<span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"Q & A: Closed circulatory system | Department of Physics | University of Illinois at Urbana-Champaign." //Physics Van | Department of Physics | University of Illinois at Urbana-Champaign//. N.p., n.d. Web. 23 May 2011. <http://van.physics.illinois.edu/qa/listing.php?id=755>. __
 * 17) __<span style="font-family: 'Times New Roman',serif; font-size: 10pt;">"The Annelids (Phylum Annelida) ." //The Earth Life Web//. N.p., n.d. Web. 23 May 2011. <http://www.earthlife.net/inverts/annelida.html>. __