Mais conteúdo relacionado


Phylum Annelida.pptx

  1. Animal Diversity: Invertebrates by Maryam Riasat PHYLUM ANNELIDA
  2. Phylum Annelida
  3. Characteristics of Phylum Annelida  Body of annelids have metamerism. Metamerism is a characteristic that features regularly repeating body segments.  This phylum includes earthworms and freshwater worms (Oligochaeta), leeches (Hirudinea), and marine worms (Polychaeta)  Annelids are sometimes called “Bristle worms”, because of the tiny chitonous bristles that they bear (except leeches) called setae.
  4. Annelid Anatomy • The body of an annelid usually consists of three parts the head (prostomium and peristomium), a series of body segments (metameres) and a terminal segment called the pygidium. • Fleshy appendages called parapodia in some annelids • Coelomate body cavity • Bilateral symmetry
  5. Organs and Organ systems • The annelids show specialization of body structures, The organ systems are well established. • Various systems of the body such as the gut, blood vessels, and nerve cord are constant throughout the length of the body penetrating each individual segment.
  6. Locomotion • Annelids have both longitudinal and circular muscles which create waves of expansion and contraction when they move called peristalsis.
  7. Skeletal System • Fluid in coelom acts as a hydrostatic skeleton
  8. Nervous system • Consists of a brain, which is connected to a pair of ventral longitudinal nerve cords, with a ganglion in each segment (metameric)
  9. Circulatory System • Annelids are the first group of invertebrates which have developed a closed circulatory system • Closed circulatory system, in which the blood is always enclosed within blood vessels that run the length of the body and branch to every segment • Several hearts (5 in earthworms) are used to pump blood through the closed circuit
  10. Respiratory system • The breathing system is not present. The exchange of gases is by diffusion through the skin into blood capillaries. The skin is kept moist by mucus and coelomic fluid.
  11. Digestive System • Unidirectional • Regional specialization (digestive organs)
  12. Excretory System • Excretory system consists of paired (metameric) metanephridia • Excretory tubes with ciliated funnels that remove waste from the coelomic fluid; open to the outside via excretory pores.
  13. Reproductive System • Sexes are usually separate with gonads occurring in each segment • Some species have gonad specific segments • Breeding is usually seasonal (spring or fall) • As gametes mature they fill the coelom and are released by the nephridia • Fertilization can be internal or external • Trochophore larvae develop, which are remarkably similar to the Molluscs Phylum Annelida
  14. Annelid Ecology  Annelids are found in the ocean, freshwater, and in terrestrial soil.  Often live in burrows in the ground and feeds on organic matter in soil.  Others feed on suspended particles that are trapped on parapodia.  Some are predaceous, and hunt by hiding in rocks and corals ambushing their prey.  Others are bloodsucking carnivores (leeches).
  15. Taxonomic summary Phylum Annelida have three major classes • Polychaeta • Oligochaeta • Hirudinea
  16. Class Polychaeta  Name means “many + long hairs”.  Many setae per body segment.  Mostly marine and dioecious.  Most segments with parapodia used for crawling, swimming, feeding and respiration.  Examples include the clam worm, scale worms, fireworms, fanworms (or featherdusters).
  17. Class Oligochaeta  Name means “few + long hairs”.  Few setae per body segment.  Terrestrial and freshwater.  No head or parapodia.  Coelom divided by septa.  Hermaphroditic  Earthworms
  18. Class Hirudinea  Name means leeches  Mostly freshwater, some marine and terrestrial.  Body usually with posterior and anterior suckers that secrete anticoagulants and consume blood.  No parapodia or setae  Clitellum present  Hermaphroditic