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Phylum Mollusca

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					         Today
1. Quiz
2. Business – graded practicals in
   your folders, new stuff on web
   site at 5:30 today, talk about
   lab report
3. Lecture on Echinoderms and
   Chordates
4. Do Labs 8 and 9
5. Next week – Lab Report Due,
   Quiz, Fetal Pig Dissection
         Common Mistakes
• Title – not descriptive enough
• Intro – background info doesn’t lead
  logically to the hypothesis, sources are not
  “scientific” enough, hypothesis not
  explicitly stated
• Method – students forget that the
  materials and methods are all one section,
  forget to say how you measured things in
  addition to what you measured
           Common Mistakes
• Results – don’t properly label figures, forget to
  have a written description of results as well as
  figures, make commentary about results (that
  should be in the discussion)
• Discussion – forget to compare results to
  previous research, state too few “problems” with
  their experiment or data, state that they “proved”
  their hypothesis (you can only support or
  disagree)
• Citations – don’t use “scientific” enough sources,
  have too many sources from web pages,
  students just write the web address (you need
  more)
                Writing Well
Avoid Wordiness
Wordiness includes being redundant (ex. little kittens),
using long words when there are good short ones
available, and including unimportant detail. Shorter
sentences are often more effective. Remember that we
want to be scientists, not lawyers or Scrabble
champions.

Bad: “It is my objective to more fully utilize my
management expertise than has heretofore been the
case…”
Good: “I want to use my management skills more fully.”

One way to avoid wordiness is to write like you talk.
Who actually says the word “heretofore”?
               Writing Well
• Know When to Use a Comma

 When deciding whether a sentence you have
 written needs a comma, read the sentence out
 loud. If you need a pause, then you need a
 comma.

 Right: My friend Pat goes to law school.
 Wrong: Yes I did take the money.
 Wrong: Plants responded to the different
 concentrations of fertilizer high medium and low.
        Review: Protostome vs. Deuterostome

Fate of
Blastopore


Type of
Cleavage


Coelom
Formation




Determinant or
Indeterminant
Cell Growth
    Phylum Echinodermata (means spiny skin)
                                          Crinoidia – sea lilies    Echinoidea – sea urchins and
                                                                    sand dollars


Asteriodia – sea stars = starfish




                                                                    Opiuroidea – brittle stars
                                    Holothuroidea – sea cucumbers
           Phylum Echinodermata
Habitat: marine

Symmetry: Bilateral larva, pentaradial symmetry in adults

Body Cavity/Germ Layers: coelomate, triploblastic

Development: Deuterostome

Skeleton: spicules embedded in dermis or a
calcareous endoskeleton
composed of spines/ossicles
     Phylum Echinodermata
Movement: tube feet of the water vascular system project out
and suction to things
              Phylum Echinodermata
Digestive System: simple, some filter feed
but many are predators that can eject
stomach and expose the prey to their
digestive enzymes

Excretory: no specialized organs

Circulatory: none, fluid circulates in the
coelom

Gas Exchange: skin gills

Nervous: no head or brain, central nerve ring
from which branches arise, eye spots
           Phylum Echinodermata
Reproduction: asexual via regeneration or sexual with
external fertilization (spawning)
                   Today
•   Look at specimens of each class
•   Look at live sea star
•   Dissect 1 starfish per group of 2
•   Look at composite slide of development
                  Starfish Dissection
     Aboral surface                            Oral surface




                                           Mouth

                                                         shell

Madreporite is opening of the water   Tube feet are the terminal end of the
vascular system                       water vascular system
                   Starfish Dissection




                                                      ampulla




                                                        shell


Starfish can evert their stomach
through their mouths and begin           Gonads may be big or small
digestion of the prey outside the body   depending on season
                   Starfish Dissection
                                          Water Vascular System


                                          Water comes in the
                                          madreporite, travels through
                                          the stone canal to the ring
                                          canal and then flows through
                                          the radial canals in each arm.
                                          The short transverse canal
                                          connects the radial canal with
                                          the ampulla. When the
                          Ring
Radial canals in   Radial canals in       ampulla fill with water, they
                          canal
each ambulacral    each ambulacral
                   ridge        ampulla   contract and move the tube
ridge
                                          feet.
   One cell stage                   Two cell stage
                                                                         Morula – solid ball
                                                                         of early cells
                                                                         (blastomeres)




                                                                            Late Gastrula
                                                 Early Gastrula
Early Blastula           Late Blastula
                                                 Gastrula looks like an indented
  Blastula is a hollow ball of cells,            blastula that is the result of gastrulation,
  no more cleavage occurring now                 which adds more cells to the cell embryo
                                                 and sorts them into distinct layers
    Characteristics of Chordates
•   Notochord
•   Dorsal hollow nerve cord
•   Pharyngeal gill slits
•   Post-anal tail
    3 Subphyla (2 are invertebrates!!!)
1) Urochordata – tunicates or sea squirts




2) Cephalochordata – sea lancelets




3) Vertebrata – the vertebrates
                Phylum Chordata
Habitat: marine, freshwater, terrestrial

Symmetry: Bilateral

Body Cavity/Germ Layers: coelomate, triploblastic

Development: Deuterostome

Skeleton: adult urochordates have nothing, larval urochordates
and cephalochordates have a notochord, vertebrates have bone
or cartilage skeleton

Movement: urochordates are sessile as adults, cephalochordates
swim by myomeres pulling against the notochord, vetebrates have
appendages like wings, fins, arms, legs
                     Phylum Chordata
Digestive System: complete


Excretory: kidneys or possible primitive kidney-like structures


Circulatory: closed, (heart, vessels)


Gas Exchange: gill slits, lungs, skin


Nervous: brain, nerve cords, eyes


Reproductive: sexual with internal or external fertilization depending on the
organism
                    Urochordata
Look at preserved tunicates and the picture of the tunicate larvae.
Cephalochordata

Look at preserved lancelets,
whole mount slide of the
lancelet, and c.s. slide of
lancelet
Class Mammalia
                             Vertebrata

                                                  Class Osteichthyes


                           Class Mammalia      Class Amphibia

                                  Class Aves
          Class Reptilia




                                                  Class Osteichthyes




                   Class Chondrichthyes            Class Agnatha
                                                                         Mammalia
                                Osteichthyes           Reptilia   Aves
                  Chondricthyes             Amphibia
        Agnatha




Ancestral
Vertebrate                  Make sure you know the distinguishing characteristics
                            of each of these 7 vertebrate classes.
Vertebrata
1. External and internal anatomy of a trout (fresh!)
2. Compare the 3 classes of fish using chart on p. 107
3. Compare skin of Amphibia, Reptilia, and Mammalia under
   scopes (already set up) – record differences
4. Take note of major features of each class. Think about:
       jaws?
       skeleton (cartilage or bone?)
       limbs for life on land?
       amniotic egg?
       ectothermic or endothermic?
       feathers?
       hair?
Look at external features. Then
     make a “window” cut.




   http://www.netaonline.org/Ima
   ge-IWFF2003.htm
anterior                                     posterior




1. Gills
2. Heart (way anterior – by mouth)    1. Swim bladder
3. Liver (very big – move it aside)   2. Gonad (varies in size!)
4. Pyloric caeca                      3. Large intestine
5. intestine                          4. Urinary bladder
6. Stomach
                                      5. Anus
7. Swim bladder
Which is more closely related to
humans and why?

Grasshopper, Squid, Starfish,
Earthworm
In a Deuterostome, the blastopore
becomes the ________________.

Do protostomes have determinant or
indeterminant growth?
What are the four characteristics
shared by all chordates?
To what class does this organism
            belong?
To what class does this organism
            belong?
Which of the following lay eggs that
           need water?
•   Turtles
•   Birds
•   perch
•   Frogs
•   Snakes
•   Kangaroos
The arrow is pointing to the ____?
Members of which phylum
  have a water vascular
         system?
The opening for the water
 vascular system is called
  the ______________.
Identify each part.
          A.

                     B.




                    ampulla



  C.
               D.
                      shell

				
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posted:12/22/2012
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