1 / 24

Porifera

Adapted from Lesser Known Protostome Phyla. SICB 2001. J.R. Garey. Porifera. Cnidaria. Ctenophora. Platyhelminthes. Gastrotricha. Gnathostomulida. Cycliophora. Rotifera. Annelida. Mollusca. Sipuncula. Nemertea. Bryozoa. Brachiopoda. Phoronida. Arthropoda. Onychophora. Tardigrada.

npratt
Download Presentation

Porifera

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Adapted from Lesser Known ProtostomePhyla. SICB 2001. J.R. Garey. Porifera Cnidaria Ctenophora Platyhelminthes Gastrotricha Gnathostomulida Cycliophora Rotifera Annelida Mollusca Sipuncula Nemertea Bryozoa Brachiopoda Phoronida Arthropoda Onychophora Tardigrada Nematomorpha Nematoda Priapulida Kinorhyncha Loricifera Echinodermata Hemichordata Chordata The Ecdysozoa = animals that molt a cuticle by hormonal (steroid) cue

  2. Phylum Nematoda

  3. Nematoda: characteristics • non-cellular cuticle • in layers • shed • pseudocoelomate • no circular muscles, only longitudinal muscles: hydrostatic skeleton • dioecious (amoeboid sperm) • little cephalization (nerve ring ~ a brain, amphids) • 80,000 spp described (>1M?) • most are benign to beneficial, 15,000 are parasitic • up to 4M/m2 in mud, billions in an acre of good farm soil • Caenorhabditis elegans is an important model organism

  4. Physiology • Specialized buccal cavity for diet • Diatoms, algae, fungi, bacteria • Plant roots, carnivores, internal parasite • Pharynx also specialized for diet • Excretion by excretory gland (renette cell) and excretory canal (not all nem’s have them) leading to an excretory pore • May also serve other functions (exoenzymes, molting fluid) • It does osmoregulation in C. elegans

  5. Reproduction • Separate sexes • but some hermaphroditic (e.g., C. elegans) • others are parthenogenic • Internal fertilization

  6. Development • Eutely: = growth by increase in cell size, not cell number • E.g. C. elegans: • 200 nerve cells, 12 epidermal cells, 172 gut cells…

  7. Human “worm” diseases

  8. Ascaris lumbricoides • in intestine of > billion people (64% in pops SE US) • Dioecious, sexually dimorphic: F > M • each F makes 200,000 eggs/day  feces  ingested  burrow through intestine wall  carried by blood to lungs  alveoli  up mucociliary escalator  swallowed  mature in intestine (30 cm long)

  9. Necator: Hookworm • Cut mucosa & feed on blood  anemia • Life cycle similar to Ascaris except infective juveniles penetrate into bare feet  burrow into int wall  lungs  swallowed  adults in intestine

  10. Trichinella (disease = trichinosos) • in 2.4% of US pop • in humans, pigs, rats, cats, dogs • Adult in sm int.  live larva  from intestine burrow  blood stream  encyst in muscle tissue  cyst consumed  hatch and live in sm int.

  11. http://www.cartercenter.org/health/guinea_worm/index.html

  12. Guinea worm

  13. Elephantiasis

  14. Enterobius: Pinworm • in 30% of children & 16% of adults in US • Eggs laid around anus at night  itch  spread eggs  ingested  hatch  adult

  15. Crop parasites Of enormous economic impact…e.g. ginseng soybean corn

  16. Fungi that snare nematodes

More Related