Laboratory                                                                                                            Zoology 1121

                                                          Phylum Nematoda

Quiz

Scientific Papers - see / use appendix
3 sources [lab book, campbell book, and library]
3-5 pages
12 pt - only Times New Roman or Helvitica fonts only
Double spaced
first person
past tense
active tense
must have graph and table in results
1. Title
2. Abstract
3. Introduction/Background
4. Materials / Methods - (..."used protocol found in Hopkins & Smith(1999) . . ")
5. Results
6. Discussion
7. Conclusion
*use citaions in 3, 4, 6 only

I. Phylum Nematoda
1. common name is roundworm
2. Classed in the pseudocoelomates
    - Have cavity between mesodermal muscle and the endodermal lining of the gut.
    - Vast amount of speciation
3. habitat = terrestrial decomposers and some parasitic

II. Nematoda Evolution
1. probably split around same time as acoelomate Platyhelminthes
2. looks as if an intermediate between platy’s and annelids but not classed as such

III. Advantages of Coelom
1. First group to evolve a body cavity – big step
2. Key idea in biology is “evolutionary speciation co-opts forms , it doesn’t create new ones”
3. Provide more area for diffusion of nutrients, wastes, gases and out of organs
4. More room for organs themselves
5. As hydrostatic skeletons
6. Facilitates increased body sized
7. Provide area for releasing reproductive gametes

IV. Phylum Characteristic
1. Multicellular
2. Eumetazoa
3. Bilateral symmetry
4. Triploblastic
5. Pseudocoelomate
6. Unsegmented
7. Elongated cylindrical body
8. Anterior End processing into 3 part pharynx (tri-radiate)

Ascaris Lumbricodes [roundworm]
1. Dioecios – either m/f
2. Males – have curved posterior end, with copulatory spicules.
3. Females -  don’t
4. Rounded body and smooth
5. Protective outer structure called a “cuticle” –secreted from epidermis, non-cellular
        - thus, syncitial function
        - Function:  1. Terrestrial – water loss
5b. Parasitic – prevents host acids from hurting
6. Tri-radiate : mouth, lips, pharynx
7. Internal cavity – filled with digestive tract or reproductive organs
8. Complete Digestion: 1 way flow through 2 openings
        Mouth – pharynx – intestines – anus
9. Reproduction Identification
    Males –
            1. Testis – produce sperm
            2. Ductus [aka. vas] Deferens –short tube for  gametes to flow from testes to a storage place
            3. Seminal vesicle – storage site of sperm
            4. Ejaculatory duct –delivery tube
    Females –
            1. Ovary – produce ova
            2. Oviduct – short tube for gametes to flow to a storage place
            3. Uterus – storage site  for ova
            4. Vagina – site of fertilization
            5. Genital pore – opening to the vagina
10. Lateral Line Excretory system – 2 pale lines running laterally along the length of the body wall
11. Circulatory System – no organs for gas exchange/circulation
12. Most parasitic roundworms are anaerobic
13.  Question: how would nourishment be take into the body and circulated?
        Answer: Semi-digested food is sucked into the mouth, is further digested and absorbed in the intestines,
                and passes into the pseudocoelom to all tissues.
14. Nervous System: consists of a ring of nervous tissue around the anterior end of the worm, with one dorsal
                and one  ventral nerve chord.
15. Support System: no, supported by hydrostatic skeleton
16. Remeber:intestines derived from endoderm
 

C. elegans
1. The major organism of biology
2. Simple systems to understand
3. Ca. 300 kbp

DNA Testing
1. read Campbell book on this (easier than lab manual)
2. agarose gel
3. TBE – buffer
4. EtBr –carcinogen stain
5. Restriction Enzyme - A degredative enzyme that recognizes and cuts up DNA at a specific sequence in the chain.
        - found naturally then isolated
        - naming is really odd – just memorize
6. 4 Constraints/ Tests
        1. Ladder – the standard
        2. Eco R1
        3. Bam H
        4. Eco & Bam
7. Uses current
        - DNA is negatively charged naturally….remember high school: neg. attract to pos.
        - DNA migrates to positive but agarose impedes flow. Smaller ones less hindrances so moves farther
8. Makes a map

IMPORTANT TERMS:
Pseudocoelomate
Dioecious
Monoecious
Bilateral
Triploblastic
Unsegmented
Mouth
Anus
Lip
Cuticle
Lateral Line
Nerve Chords
Epidermis
Mesoderm
Gastroderrn
Copulatory Spicules
Pharynx
Intestine
Seminal Vesicle
Testis
Ejaculatory Duct
Ovaries
Oviduct
Uterus
Genital Pore
Vagina
Electrophoresis
agarose gel
restriction enzymes (Eco RI, Bam HI)
DNA Ladder
TBE Buffer
Ethdium Bromide