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Gastrotricha

Gastrotricha. Presented by: Kalana Rupasinghe Jilllian Savoy James Schumacher. Taxonomic Grouping. Kingdom Animalia Phylum Gastrotricha Class Gastrotricha Order Macrodasyida Chaetonotidae. Gastrotricha Structure and Anatomy. Spiny Bristles:

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Gastrotricha

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  1. Gastrotricha Presented by:KalanaRupasingheJilllian Savoy James Schumacher

  2. Taxonomic Grouping Kingdom Animalia PhylumGastrotricha ClassGastrotricha OrderMacrodasyidaChaetonotidae

  3. Gastrotricha Structure and Anatomy Spiny Bristles: Thorny structures used as a means of intimidation as well as being about to grapple to objects as a means of locomotion. Esophagus: Tube-like structure in which mineral foods pass from the mouth to the intestine Salivary Gland: Secretes sticky acidic substance used to breakdown the small foods that it consumes. Usually less that 1mm, rarely up to 3mm. Anus:Small opening in which waste is excreted as very small castings. Intestinal Track: Structure in which consumed minerals are broken down into vital nutrients before secretion.

  4. Gastrotricha - Diet Gastrotricha are very small marine flatworms that will feed on small organisms or materials, such as: • Blue or Green Algae • Protists - Slime molds, amoebas, planktons • Unicellular Algae - Chlorella • Bacteria - algae, and other such bacteria • Detritus - Decomposes dead matter

  5. Environment • Commonly found in marine and benthic environments -as such, they are huge contributors in their community • Can be found in terrestrial areas, typically in lotic water areas. • Notably found in organic sediment in eutrophic and lentic biotopes. • Also found in loose sediment or epi-benthic, compacted into mud or layered organisms

  6. Evolution • Little is known of the evolution of gastrotricha, but recent research did come to light • Over time, the Splanchnic muscles developed in a circular pattern. • Result of better digestion of prey, namely diatoms. • Allowed better mobility • Additionally, the longitudinal muscle and radial dilutions developed in the gut tube

  7. Evolution (Cont.) • Main problem of the lack of information of Gastrotricha is the non-existence of fossil evidence • Morphologically belong to a protostome (clade) that consist of other phylum's based on molecular evidence: • Nematodes + Nematomorpha + Gastrotricha • The common ancestor that the protostome arose from, is debated from either free-living turbellarian flatworms or coelomates • Ally themselves with lophotrochozouns based on SSU rRNA sequences Gastrotricha Nematoda Nematomorpha lophotrochozouns

  8. Evolution (Cont.) • Being more closely related to the phlumnematoda, what differs between them can be seen in their embryonic stages • Gastrotricha’s cell cleavage results to being radialholobolistic pattern • Nematoda’s cell cleavage results to being spiral holobolistic pattern

  9. Reproduction: Marine Species • Marine species are mostly hermaphroditic: possess both male and female sex organs (with only one being functional at a time) • Sperm is transferred via a spermatophore through internal fertilization • Eggs are produced in small numbers at a time • No larval stage; hatch as small Gastrotrichs and reach sexual maturity within 2-3 days

  10. Reproduction: Freshwater Species • Freshwater species are mostly parthenogenic; all functionally female (asexual reproduction) • Produce two types of eggs: • - The quick-to-hatch egg(1-4 days) also seen in marine species • - A tougher overwintering egg that can withstand extreme temperatures, allowing it to exist in unstable environments

  11. Order: Macrodasyida • 310 species; 6 families • Mainly marine (and hermaphroditic) • Elongate body • A complex distribution of adhesive tubes • Myoepithelial pharynx with • inverted Y-shaped lumen • Presence of pharyngeal pores • Cellular epidermis surrounded by a soft cuticle • Internal circular musculature

  12. Order: Chaetonotidae • Uniform body covered with a thick layer of soft homogenous cuticle • Overall shape : ten-pin or bottle-shaped • Commonly found in epi-benthic , interstitial , and marine • environments • Can be found in brackish estuaries • Contained within excretory system lie • rapidly beating cilia as a way of removing • excretory waste (protonephrida) • Under order: consist of 450 different species

  13. Thank You for Listening!!!And we hope you have enjoyed this presentation!!!See references

  14. References Balsamo, Maria, Jean-Loup d’Hondt, JacekKisielewski, and Lara Pierboni. "Global diversity of gastrotrichs (Gastrotricha) in fresh waters." Hydrobiologia The International Journal of Aquatic Sciences (2007). Web. 6 Mar. 2013. Hochberg, R. "Musculature of the primitive gastrotrich Neodasys (Chaetonotida):." Marine Biology (2004): 316-22. Web. 4 Mar. 2013. Litvaitis, Marianne K., and Rick Hochberg. "Macrodasyida (Gastrotricha): A Cladistic Analysis of Morphology." Invertebrate Biology 120.2 (2001): 124-35. Print. Litvaitis, Marianne K., and Rick Hochberg. "The musculature of Draculiciteriatessalata (Chaetonotida,." Hydrobiologia (2001): 155-61. Web. 6 Mar. 2013. Paps, Jordi, and Marta Riutort. "Molecular phylogeny of the phylum Gastrotricha: New data brings together molecules and morphology." Molecular Phylogenetics and Evolution 63.1 (2012): 208-12. Print. Valentine, James W. On the Origin of Phyla. Chicago: The University of Chicago Press, 2004. 361-78. Print.

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