Annelida

Hirudinea

Hirudo medicinalis

Oligochaeta

• Commonly referred to as the medical leech
• The medical leech is parasitic
• It is brown or black with six long reddish stripes
• The leech has five pairs of eyes
• The leech resides in freshwater
• It is amphibious, requiring both land and water for survival
• It feeds off the blood of animals

Polychaeta

• commonly known as earthworms
• few setae
• no parapodia
• simple cone-shaped head
• no sensory appendages
• light is detected by photoreceptor cells in the skin
• tunnel by swallowing soil
• hermaphroditic
• over 8,000 species

Pompeii worm

Annelid Reproduction

Polychaeta

• Deep-sea polychaetes
• Reside in tubes near hydrothermal vents along the sea floor
• Can grow up to 5 inches long
• Grey with red tentacles
• Their tail ends are in tubes at 176 degrees
• Head end sticks out of tube into 72 degree water
• Have a symbiotic relationship with bacteria for insulation

Christmas tree worm

• Occur in a variety of colors
• They are sedentary polychaete worms
• Tube dwellers
• Much of the worm is anchored in its burrow
• Reside in tropical oceans
• Christmas tree worms grow up to 2 inches long
• They reproduce through sexual reproduction
• Extend spires for capturing plankton
• They are sensitive to changes in the environment and retract into their burrows

Sexual-

Worms can be either hermaphroditic or dioecious. The fluid is transferred from the male pore to the female pore.

Female annelida reproductive organs may include either a female pore, or in species that copulate, a vagina.

Sperm capsules or spermatophores help to transport the sperm to fertilize the ovary

Hirudinea

Annelid Reproduction

• commonly referred to as leeches
• posterior and anterior sucker
• 34 segments
• live in primarily freshwater ecosystems
• can be predators and parasites
• 2 to 10 eyes
• medical leech: aquatic bloodsucking leech with jaws

Asexual-

• fragmentation- the posterior or anterior breaks off and forms a new annelid
• budding- a bud comes off of the annelid and eventually turns into a duplicate annelid
• fission-the annelid divides into two daughter annelids

Hirudinea

Hirudo medicinalis

Annelida

• The leech injects an anesthetic so that its presence is not detected
• Its three jaws work back and forth during the feeding process
• After a feeding the leech may increase in size by 8 to 11 times its original body size
• Leeches only feed about twice a year
• The leech has been used in medicine to remove "bad blood"

Ramsey Walker

Characteristics

Size- range from a fraction of a centimeter to over 10 feet.

Chaetogaster annandalai

Giant Earthworm

Body Structure

Distinguishing Characteristics

Cerebral ganglion- the primitive brain located near the front of the worm.

Nerve cord- connected to the brain, runs along the underside of the annelid's body. Carries sensory information from segments to the brain.

Metameric segmentation- the repetition of organs and tissues at intervals along the body of an annelid.

Coelom- fluid-filled cavity between the outer body wall and the digestive tract, often a storage area for gametes.

Body wall- Annelids have a body covered by an external cuticle.

Body Structure

Annelid Appendages

Segmentation- Each segment in a segmented worm contains many of the same organs, including those used in digestion, movement, excretion, and circulation.

Septa- internal walls that

separate the body segments.

Chaetae- stiff bristles made of chitin along the annelid body.

Clitellum- A raised band made up of reproductive segments.

Parapodia- unjointed limbs that assist in movement of annelids.

Nuchal organ- a sensory groove present at the posterior end of an annelid.

Lateral organ- a sensory groove present at the side of an annelid worm.

Oligochaeta

Earthworm

• commonly found living in soil
• there can be more than a million earthworms in an acre of land
• largest earthworm was 22 ft long
• they can eat their body weight in one day

• feed on both living and dead organic matter
• require oxygen and moisture to survive

Works Cited Continued

Basic Body Structure

All annelids are bilaterally symmetrical with a cylindrical body shape divided both externally by indentations and internally by segments.

Body Structure

• Ramel, Gordon. "The Phylum Annelida." The Annelids (Phylum Annelida). N.p., n.d. Web. 28 Mar. 2015. <http://earthlife.net/inverts/annelida.html>.
• Rouse, Greg W., Fredrick Pleijel, and Damhnalt McHugh. "Annelida." Annelida. N.p., 1998. Web. 28 Mar. 2015. <http://tolweb.org/Annelida>.
• "20 Interesting Earthworm Facts You Might Not Have Known." Earthworm Facts. Earthworm Facts, 2007. Web. 20 Mar. 2015. <http://www.earthwormfacts.net/>.

Anterior- The front of the annelid body, nearest the head.

Prostomium- head region of an annelid.

Peristomium- The first true segment of an annelid worm usually bearing the mouth.

Posterior- The tail end of the annelid body.

Annelida

The phylum Annelida is comprised of segmented worms.

They are found in terrestrial, marine and freshwater ecosystems.

Annelid Appendages

Antennae- a conductor by which electromagnetic waves are sent out and received.

Palps- a pair of sensory appendages that arise from the head of annelids.

Setae- stiff bristle like hairs

Annelid Development

Annelid eggs exhibit spiral cleavage.

Spiral cleavage- development process with early differentiation of regions through clockwise and counterclockwise cell divisions.

Polychaetes have a free-swimming larval form.

Oligochaetes and Hirundinea develop within a cocoon.

Annelids have been seen to live for up to 27 years.

Hirudinea

Kinabalu Giant Red Leech

• grows up to a foot long
• only feeds on other worms

Polychaeta

• Most complex class of Annelids
• Evolved first
• Primarily marine worms
• over 15,000 species
• turn over sediment on the ocean floor bottom
• they have antennae, parapodia, setae, tentacles, & palpi
• inhabit depths of over 16,405 ft

Works Cited

• Abarenicola Pacifica. Abarenicola Pacifica. Wetvideocamera, 22 Mar. 2011. Web. 18 Mar. 2015. <https://youtu.be/NBBktwAI_kA>.
• Aglaophamus. Digital image. N.p., n.d. Web. 22 Mar. 2015. <http://www.iopan.gda.pl/projects/Polychaeta/list/images/Aglaophamus_2.jpg>.
• "Annelid | Invertebrate." Encyclopedia Britannica Online. Encyclopedia Britannica, 18 Dec. 2013. Web. 22 Mar. 2015. <http://www.britannica.com/EBchecked/topic/26308/annelid>.
• Annelid Body Structure. Digital image. N.p., n.d. Web. 20 Mar. 2015. <http://www.rugusavay.com/wp-content/uploads/2015/03/rugusavay-com.jpg>.
• Annelid Body Structure. Digital image. N.p., n.d. Web. 21 Mar. 2015. <http://yhsbiology.wikispaces.com/file/view/earthworm_structure/48568043/earthworm_structure>.
• Annelid Coelom. Digital image. N.p., n.d. Web. 22 Mar. 2015. <http://biology.unm.edu/ccouncil/Biology_203/Images/Protostomes/Coelomate.JPG>.

Works Cited Continued

• Annelid Worm. Digital image. N.p., n.d. Web. <dn.c.photoshelter.com/img-get/I0000gJJ5H7xyvDk/s/860/860/Eathrworm-de-Tail.jpg>.
• "Annelida." : Reproduction. N.p., 5 Mar. 2007. Web. 22 Mar. 2015. <http://annelidsh.blogspot.com/2007/03/reproduction.html>.
• "Annelida." Infoplease. Infoplease, 2012. Web. 28 Mar. 2015. <http://www.infoplease.com/encyclopedia/science/annelida-annelid-characteristics.html>.
• Blaxland, Beth. Annelids: Earthworms, Leeches, and Sea Worms. 2003 ed. Philadelphia: Chelsea House, 2003. Print.
• Earthworm. Digital image. N.p., n.d. Web. 20 Mar. 2015. <http://www.critterzone.com/animal-pictures-nature/stock-photos/AW040904_36.jpg>.
• Earthworm. Digital image. N.p., n.d. Web. 26 Mar. 2015. <http://www.whyguides.com/wp-content/uploads/2009/06/earthworm11.jpg>.
• Figure 5. Digital image. N.p., n.d. Web. 23 Mar. 2015. <http://tolweb.org/tree/ToLimages/eyes.jpg>.
• "Information On Annelids – Anatomy – Classification – Habitats." Information On Annelids – Anatomy – Classification – Habitats. Nature & Animals, Science, 29 Mar. 2013. Web. 19 Mar. 2015. <http://www.rugusavay.com/information-on-annelid-anatomy-classification-habitats/>.

Works Cited Continued

Classes

• Leech, Hirudinea. Digital image. N.p., n.d. Web. 23 Mar. 2015. <http://www.wlin.pl/assets/1606/08_Hirudinea_02_normal.jpg>.
• Leeches. Digital image. N.p., n.d. Web. 20 Mar. 2015. <https://maria911.files.wordpress.com/2010/09/leeches1.jpg>.
• Monster Leech Swallows Giant Worm- Wonders of the Monsoon: Episode 4 - BBC Two. 2014. BBC, 30 Sept. 2014. Web. 24 Mar. 2015. <https://youtu.be/0fGGz6d3vC4>.
• Myers, Phil. "Annelida (segmented Worms)." Animal Diversity Web. Animal Diversity Web, 19 Sept. 2001. Web. 20 Mar. 2015. <http://animaldiversity.org/accounts/Annelida/>.
• Nuchal Organs. Digital image. N.p., n.d. Web. 20 Mar. 2015. <http://tol.tolweb.org/tree/ToLimages/nuchal.jpg>.
• Oligochaeta. Digital image. N.p., n.d. Web. 19 Mar. 2015. <http://www.biokids.umich.edu/files/11024/1018045569_large.jpg>.
• "Phylum Annelida." Phylum Annelida. N.p., 2002. Web. 20 Mar. 2015. <http://www.fossilmuseum.net/Tree_of_Life/PhylumAnnelida.htm>.
• Polychaeta. Digital image. N.p., n.d. Web. 24 Mar. 2015. <http://invertebrates.si.edu/Features/images/families/polychaeta/myrianida.jpg>.
• Pompeii Worm. Digital image. N.p., n.d. Web. 23 Mar. 2015. <http://cdn1.arkive.org/media/1C/1C2AF8A7-F7FD-4EB3-B60D-D1F4AD1D0C46/Presentation.Large/Pompeii-worm-showing-coat-of-proteobacterial-epi-symbionts.jpg>.

Polychaeta

Oligochaeta

Hirudinea