Category: Invertebrate Unit

Crayfish Worksheet

Name(s)__________________________________ Group______ Date ________ Period_____

Crayfish Dissection Worksheet

1. What structures are used for capturing prey and securing and eating food?

 

 

2. How are the antennae, chelipeds, other walking legs, and swimmerets related?

 

3. What are the main structures you could have observed when you removed the exoskeleton of the abdomen and tell the function of each?

 

 

 

 

4. Is the crayfish most vulnerable to its enemies from the dorsal or ventral side? Why?

 

5. The crayfish usually molts, or sheds its exoskeleton, twice a year. Why does the crayfish “hide” after it molts?

 

 

6. Name the appendages found on the head of a crayfish & tell the function of each.

 

 

 

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7. Of the systems studied, which two are most unlike the related human system? Why?

 

 

8. Although the crayfish has an inflexible cephalothorax, the crayfish is classified as a segmented animal. Why?

 

 

9. Name the appendages found on the thorax of the crayfish and tell the function of each.

 

 

 

10. Name the appendages on the abdomen of the thorax and tell the function of each.

 

 

 

 

11. Label the drawing of the crayfish.

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Clam Dissection Questions

 

 

  Clam Dissection Questions

 

Pre-lab:
1. Give the kingdom, phylum, and class for the clam.

 

2. Describe the body of bivalves.

3. How do bivalves move?

4. Why are they called bivalves?

5. Is their digestive tract complete or incomplete?  Explain your answer.

 

6. Do bivalves show cephalization?  Explain your answer.

 

7. What are siphons & what is their purpose?

 

8. How can you distinguish a mussel from a clam?

 

9. Adults are usually sessile, but the larva or _________________ is free-swimming.

10. Are bivalves protostomes or deuterostomes?

11. Their body cavity is called the _____________ cavity.

12. Body organs make up the ___________ mass and are protected by the _____________ which secretes the ___________.

13. Is circulation open or closed?

14. Give several examples of bivalves.

Lab Questions:
1. What is the oldest part of a clam’s shell called and how can it be located?

 

2. What do the rings on the clam’s shell indicate?

3. Name the clam’s siphons.

4. What holds the two shells together?

5. What muscles open & close the clam?

6. Describe the inside lining of the shell.

7. What is the function of the tooth-like projections at the dorsal edge of the clam’s valves?

8. Where is the mantle located in the clam?  What is its function?

 

9. Describe the clam’s foot.

 

10. What is the mantle cavity?

 

11. How do clams breathe?

12. What helps direct water over the gills?

13. Where are the palps found and what is their function?

 

14. Describe the movement of food from the current siphon through the digestive system of the clam.

 

 

15. Where is the clam’s heart located?

 

16. What are the parts of the clam’s nervous system?

 

17. Why are clam’s referred to as “filter feeders”?

 

18. Label the internal structures of the clam and draw arrows showing the pathway of food as it travels to the clam’s stomach:

Crayfish Dissection

 

Crayfish Dissection

 

By Day:    Day 1        Day 2        Day 3

By Region: External Anatomy    Internal Anatomy

By Topic:      Skeletal       Integumentary     Cardiovascular     Muscular    Endocrine    Nervous
Reproductive     Respiratory    Excretory    Digestive

 

You must create a series of labeled drawings that illustrate the structures outlined below:

Day 1

I. Abdomen – Ventral View          (Day 1)         top

Place the crayfish supine (ventral surface up) on the dissecting tray and DRAW the following:

 

  1. Telson (What is the telson’s function?)
  2. Uropod  (Describe the location of the Uropod to the telson.   How do the add to the telson’s function?)
  3. Anus (In which of the two structures above did you find the anus? 1 or 2 way digestive system?)
  4. Swimmerets -numbered in pairs, 1-5 w/ the 5th one the most posterior (What is their function, and how is it different from the telson’s function?)
  5. Is your Crayfish a male or a female (Note the anterior-most swimmeret.   In the male, its function is to guide the sperm toward the female during copulation; as such, it will be enlarged, and pointed anteriorly in the male.  In the female there is no difference between the swimmerets)?  (Describe the appearance of the crayfish’s swimmerets in your answer.)
  6. Walking Legs (How many are there?  In terms of this feature alone, is this organism closer to an insect, or an arachnid?)
  7. Chelipeds – some people like this meat the best . . . (What is their function?)

 

II. Head – Ventral View             (Day 1-2)         top

 

  1. Mandibles – 2 – hard & white  (What are they equivalent to in humans?  How is their action – think direction of movement – different from that of humans?)
  2. Maxilla – softer w/ jagged edges  (Given the difference in texture, how is their function different from that of the mandibles?)
  3. Maxillapeds, or “mouth-feet” -3 pairs  (What is their function?  Why not use the Chelipeds?)
  4. Green Gland Ducts – (From what organ do they open out?  What is the equivalent organ in humans? What is the purpose of the duct?  Is its location at all disturbing to you?)

 

 

II. Cephalothorax – Dorsal View             (Day 1-2)         top

  1. Rostrum (What is cephalization?  Given that, what organ would you expect to be inside the rostrum?)
  2. Eyes (Does this organism have binocular vision – depth perception, why or why not?)

     


    Eye

     

  3. Carapace (What is the function of the carapace?  What two body systems in humans perform equivalent functions?  The support function is in reference to one system in particular; given the external location of the carapace, explain the name of the type of system compared to our own, internal variety.  The support function implies specifically the attachment of organs of what body system to the inside of the carapace?

Day 2

Make a Dorsal Midline Incision from the posterior end of the thorax to the posterior end of the rostrum using the rounded scissors w/ the rounded end down! Open the carapace and pin it back.

III. Thorax – Dorsal View, Part I          (Day 2)         top

  1. Heart & Ostia – the opening on the heart’s superior surface (Is this a sign of an open or closed circulatory system?  Differentiate between the two in your answer.)
  2. Gills (What are they equivalent to in humans?  To what body system do they belong?  Why are the gills so feathery – i.e., how does this aid in their function?)
  3. Cardiac Stomach -draw whole (There appear to be fibers attached to the outside of the stomach.  What is their purpose in relation to the stomach and the esophagus?)

IV. Thorax – Dorsal View, Part II         (Day 2)         top

  1. Remove one gill and draw on high power (What is the red/pink material within each “finger” of each gill?  How does this material relate to the function of the gill?)
  2. GENTLY remove one walking leg, and you will see that a gill is attached to each walking leg.  (How is this important to the function of the gills?  In your answer refer to the different requirements of the body during times of high physical activity, and how they are related to the gill-walking leg connection.)
  3. Cut open the Cardiac Stomach and draw the Gastric Mill – reddish-brown lateral “teeth” – on high power  (What is their function?  What type of digestion involves the gastric mill?  Do we accomplish that type of digestion in our own stomach?)

Day 3

V. Thorax – Dorsal View, Part III         (Day 3)         top

Gently remove the Heart.

  1. The Intestine (Given its location posterior to the stomach, what is its function?  What function of the stomach is lacking in the intestine?)
  2. The Hepatopancreas Gland (What two organs is this equivalent to in humans?  What are some of the functions of this gland?  How is its location important to its function?)
  3. The Seminifierous Tubules or Ovaries  (What is the function of each? To what body system do these belong?  Which of the two does your specimen contain?  How is this related to the swimmerets?)

 



 

VI. Thorax – Dorsal View, Part IV         (Day 3)         top

Gently remove the Cardiac Stomach.

  1. Esophagus  (Describe how it’s position relative to the stomach is different from the worm and the human.)
  2. Green Gland (What is/are the equivalent organ(s) in humans?   Do/does the analogous organ(s) appear in pairs in humans?  To what body system do the green glands belong?  What organ in our equivalent body system is missing in the crayfish?)
  3. Brain (Describe the appearance of the brain and the nerves in terms of the type of symmetry.  There are nerves that are attached to the front and the back of the brain.  Describe the function of both the anterior and the posterior nerve pairs.)

VII. Abdomen – Dorsal View, Part I       (Day 3)        top

Make a Dorsal Midline Incision from the anterior end of the abdomen to the posterior end of the abdomen using the rounded scissors w/ the rounded end down! Open the exoskeleton and pin it back.

 

In order for a Crayfish to determine BALANCE, it must insert a grain of sand in one of it’s appendages.
Every time it molts and makes a new exoskeleton, it must get a new grain of sand!
(In what part of the body is that function taken up by the human body?)

 

  1. Dorsal Blood Vessel  (Is this vessel sending the blood to, or away from, the heart?  What name would we give to that type of vessel in our body?)
  2. Large Intestine (How is the location of this organ related to the name of this section of the body [it is NOT a tail]?  What is the function of the large intestine?  Given it’s contents, is it wise, or unwise, to eat it when eating a lobster?  Explain.)
  3. Abdominal Flexor Muscles  (How do muscles function, by shortening,   lengthening, of both?  Moving the abdominal flexor muscles will cause flexion, but what is flexion?  How will the abdomen – it is NOT a tail – change shape during flexion?  What direction will the crayfish move during flexion?  Given the size and strength of the muscle, during what circumstances would the crayfish use this muscle over its walking legs?)

VIII. Abdomen – Dorsal View, Part II        (Day 3)        top

Gently remove the Abdominal Flexor Muscles.

  1. Ventral Blood Vessels  (Given that there is no main ventral blood vessel, how does the blood return to the heart?  Is this a sign of an open or closed circulatory system?)
  2. Ventral Nerve Cord  (To what phylum does the crayfish belong?   How is the location of the nerve cord different from creatures in our own phylum?   Name our own nerve cord.  How is the protection of the nerve cord different in both phyla?)

Drawings:

  1. Use a PENCIL!!

  2. Make the drawings “larger than life” size, as the specimens are so small.

  3. Draw the general shape (outline) and location of the organs, as the squiggles so many of you use to “shade” your drawings make your drawings sloppy and hard to interpret.

  4. Include Labels on all drawings.

  • Labels should start outside the drawing, and be connected to the structure by arrows with tips (===>).

  • The Tip of the arrow should be touching the structure.

  • Be sure to include the magnification for any drawings done with the dissecting microscope.

Hang on to the drawings; they will all be handed in later, together with some questions to answer!


Day 1        Day 2        Day 3         top

Modified from  Lazaroff Biology

 

Chordates

Chordates
All Materials © Cmassengale  

Characteristics of Chordates

  • All chordates have a notochord, dorsal nerve cord, pharyngeal pouches, & postanal tail at some time in their life
  • Notochord is a firm, flexible rod of tissue located on the dorsal side of the body that becomes part of the endoskeleton in vertebrates
  • Dorsal nerve cord is a hollow tube lying dorsal to the notochord that becomes the brain & spinal cord in vertebrates
  • Pharyngeal pouches are small outpockets of the anterior part of the digestive tract that become gills in aquatic chordates & jaws, inner ear, & tonsils in terrestrial chordates
  • Postanal tail consists of muscle tissue & lies behind the posterior opening of the digestive tract

Subphyla of Chordates

  • The Phylum Chordata  includes all of the vertebrates, as well as two groups of marine animals that lack backbones and are called invertebrate chordates
  • The phylum is divided into three subphyla, determined by the development of the notochord
  • Subphylum Cephalochordata contains about 24 species of blade-shaped animals known as lancelates that retain the notochord, dorsal nerve chord, pharyngeal pouches, and postanal tail throughout their life
  • Subphylum Urochordata  contains 2,000 species commonly called tunicates because their bodies are covered by a tough covering, or tunic
    * Called sea squirts because they shoot out a stream of water when touched
    *Sessile, barrel-shaped, filter feeding animals that live on the sea bottom
    *Adults have a pouch-like pharynx with slits
    *Adults do not have a notochord, dorsal nerve cord, or postanal tail
  • Subphylum Vertebrata is the largest subphylum in which the notochord is replaced with vertebrae
    *  Skeletons consist of bone &/or cartilage
    * Brain is protected by a cranium
    * Well developed 4 chambered heart with a closed circulatory system
    * Includes fish, amphibians, reptiles, birds, & mammals

Fish, Amphibians, Reptiles, Birds, and Mammals
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Chapter 33 AP Objectives

 

Chapter 33     Invertebrates
Objectives
Sponges
1.From a diagram, identify the parts of a sponge (including the spongocoel, porocyte, epidermis, choanocyte, mesohyl, amoebocyte, osculum, and spicules) and describe the function of each.
Eumetazoa
2.List the characteristics of the phylum Cnidaria that distinguish it from the other animal phyla.
3.Describe the specialized cells that are found in Cnidarians.
4.Describe the two basic body plans in Cnidaria and their role in Cnidarian life cycles.
5.List the four classes of Cnidaria and distinguish among them based on life cycle and morphological characteristics.
Bilateria
6.Distinguish between:
a. diploblastic and triploblastic development
b. acoelomates and coelomates
c. gastrovascular cavity and alimentary canal
d. protostome and deuterostome
7.List the characteristics of the phylum Platyhelminthes that distinguish it from the other animal phyla.
8.Distinguish among the four classes of Platyhelminthes and give examples of each.
9.Describe the generalized life cycle of a trematode and give an example of one fluke that parasitizes humans.
10.Explain how trematodes evade detection by the immune systems of their hosts.
11.Describe the anatomy and generalized life cycle of a tapeworm.
12.Describe unique features of rotifers that distinguish them from other pseudocoelomates.
13.Define parthenogenesis and describe asexual forms of rotifer reproduction.
14.Define lophophore and list three lophophorate phyla.
15.List the distinguishing characteristics of the phylum Nemertea.
16.Explain the relationship between nemerteans and flatworms.
17.List the characteristics that distinguish the phylum Mollusca from the other animal phyla.
18.Describe the basic body plan of a mollusc and explain how it has been modified in the Bivalvia, Cephalopoda, Gastropoda, and Polyplacophora.
19.List the characteristics that distinguish the phylum Annelida from other animal phyla.
20.Distinguish among the three classes of Annelida and give examples of each.
21.Describe the adaptations that enable some leeches to feed on blood.
22.List the characteristics of the phylum Nematoda that distinguish it from other wormlike animals.
23.Give examples of both parasitic and free-living species of nematodes.
24.List the characteristics of arthropods that distinguish them from the other animal phyla. List the three features that account for the success of this phylum.
25.Describe advantages and disadvantages of an exoskeleton.
26.Distinguish between hemocoel and coelom.
27.Define and distinguish between the major arthropod lines of evolution represented by:
a. Cheliceriformes
b. Hexapoda
c. Crustacea
d. Myriapoda
28.Describe three specialized features of spiders.
29.Describe two features that may account for the great diversity of insects.
Deuterostomia
30.List the characteristics of echinoderms that distinguish them from other animal phyla.
31.Distinguish among the six classes of echinoderms and give examples of each.
32.Explain why the phylum Chordata is included in a chapter on invertebrates.
33.Describe the developmental similarities between echinoderms and chordates.
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