Ch 11 Pseudocoelomates soo-doe-see-low-mates Acrobeles complexus Pseudocoelomates (Aschelminthes) 7 phyla: Do not molt
Rotifera Acanthocephala Molt Nematoda Nematomorpha Kinoryncha Loricifera Priapulida
Phylogeny Two Hypothesis 1. Phyla related based on anatomy, pseudocoelom, cuticle, muscular pharynx, and adhesive glands. 2. Phyla not related, thus are polyphyletic absence in single unique feature independent
evolution a. similarities result of convergent evolution in similar environments. Pseudocoelomates A heterogeneous group: Size: microscopic several meters some are exclusively marine;
some (e.g., nematodes) live in a variety of habitats, esp. soil; and some are exclusively parasitic Plant ectoparasite A. lumbricoides Pseudocoelomates
Common characteristics: 1. First animal to posses a distinct body cavity, but they lack the peritoneal lining and membranes (mesenteries) 2. Pseudocoelom- fluid filled, gelatinous substance, serves for circulation, aids in digestion, acts as hydroskeleton. Common characteristics:
1) Pseudocoelom body cavity (pseudocoelom/ pseudocoel) a space b/w gut and mesodermal components of body wall Body cavity is not lined with a mesodermal sheet
Does not cover inner surface of body wall Common characteristics: 1) Pseudocoelom Pseudocoelom is spacious, fluid-filled and Contains visceral organs No muscular tissue associated with gut tract No membranes suspend organs in
body cavity Common characteristics: 2) Eutely Eutely (thrift) a condition in which the number of cells is constant (i.e. C. elegans = 959 adult) Common characteristics:
3) complete digestive tract (mouth and anus) Found in most other higher animals http://www.wormatlas.org/handbook/alimentary/alimentary2.htm Common characteristics: 1. Bilateral symmetry 2. Unsegmented, tribploblastic, and
cylindrical in cross section 3. Protonephridia 4. Some cephalization is evident (primitive brain, mouth, sense organs) 5. Dioecious 6. Complete digestive tract (mouth and anus) 7. All have cuticle
Evolutionary advantages of pseudocoel: Greater freedom of movement Space for development and differentiation of organ systems (ie. digestive, excretory) differentiation: process by which cells become different, specialized Simple means of circulation/distribution of materials throughout body
Storage place for waste products to be discharged to outside Hydrostatic skeleton Fluid enclosed by muscular wall Pseudocoelomates Organ systems present: Digestive system Excretory system
Nervous system Reproductive system Organ systems absent: Circulatory system Respiratory system Phylum Rotifera
Phylum Rotifera (non Molting) rota= wheel (wave of beating cilia) fera= bearer Freshwater, some marine B/w grains of sand
Many resistant to desiccation dioecious http://micro.magnet.fsu.edu/primer/techniques/phasegallery/images/rotifer.jpg Phylum Rotifera Brain Muscular pharynxmastax
Protonephridia with flame cells Pedal glands Internal Anatomy of a Typical Rotifer Phylum Nematoda The roundworms
Phylum Nematoda (Molt) 16,000 species 500,000 possible Cylindrical body (vermiform) Excretory system renette Mostly dioecious
Only longitudinal muscles Undulate/thrash around (dont crawl) movie Phylum Nematoda Noncellular cuticle with several layers Primary layers of cuticle- cortex, matrix
layer and basal layer Maintains internal hydrostatic pressure Provides mechanical protection Resists digestion by host (in parasitic nematodes) Phylum Nematoda (contd) Found
everywhere Oceans (free living and parasitic) Polar ice Hot springs Soil Some play an important role
in nutrient 5 billion per acre Phylum Nematoda (contd) Eat just about every type of organic
material Rotting substance Living tissue Parasites of nearly all plant and animal species!
Do these questions now What type of germ layer lines the pseudocoelom in nematode embryos? What organ systems are present/absent in pseudocoelomates What are the advantages of having a pseudocoelom vs. no coelom?
Ascaris lumbricoides Human parasite Up to 30cm long 1.2 billion people Many in southeast US Females lay 200,000
eggs a day Unsanitary habits contaminate ground Ingest eggs Hatch bury into veins lungs pharynx Life cycle of Ascaris lumbicoides
Figure 11.10 Migrate to Molt Pinworms Most common parasite in US
30% children; 16% adults Large intestine Lay eggs (first-stage larva) in perianal area at night Itch and Spread Fecal oral route Pinworm life cycle
William Shakespeare - The basics. Thought to be born on April 23, 1564 in Stratford-upon-Avon. Died April 23, 1616. Considered to be the best writer inthe English language. Surviving works: 38 plays, 154 sonnets, 2 long narrative poems, and several...
About US Lacrosse video clip . About the Sport video clip. This is Lacrosse video . ... US Lacrosse also commits significant resources to the proper training of officials for both the men's and women's game. Read . more about...
US OPEN. PEBBLE BEACH, CA. June 14 - 20, 2010. Join Broach Sports Tours at the 2010 U.S. Open Golf Championship to see the. game's most brilliant players fight for victory at the famed Pebble Beach Golf Links in
S 5 Capillary exchange by: Diffusion, vesicle transport, bulk flow, mediated transport S 6 Fig. 12.40 Diffusion is the most important mode of exchange of nutrients S 7 Figure 12.41 Crystalloids Colloids Bulk Flow S 8 = colloids (impermeable proteins)...
Presenting David Bryan Adam Hongwang Zhang IN Cheese & Yogurt… Art, Murder, Mayhem The History Possibly Found by Arab Nomad Greeks said Aristaeus found it Romans made their own types Anne Pickett Found 1st U.S. Business in 1841 Types of...
Liability Negligent Retention. Failure to terminate an employee who is clearly unsuitable for the job. Liability Negligent Supervision. Failure to coordinate, control, or direct trainee conduct that may cause injury. This can include failure to use reasonable care in addressing...
One question? Two examinations? Would you investigate? Two examinations Fundoscopy BP Giles Elrington neurological examination Case 1 35 year old male Three week history Sharp, severe pain bilaterally and posteriorly lasting 10 seconds repetitively. One question? Two examinations? Would...
What is the variable? Is this a fair test? Variable Manipulated - the one factor that is changed in the test Responding - because the manipulated variable is changed, how does it affect the test? Ex: Think about Jill's experiment?...
Ready to download the document? Go ahead and hit continue!