Worksheet for Morgan/Carter Laboratory #19 Animals II Nematoda, Arthropoda, Echinodermata and Chordata BE SURE TO CAREFULLY READ THE INTRODUCTION PRIOR TO ANSWERING THE QUESTIONS!!! You will need to refer to your text book to answer some of the questions on this worksheet. INTRODUCTION Thirteen Characteristics for Classifying Animals (Table 19.1) As part of both Labs #18 and #19, you will complete Table 19.1 which is a separate document. For each organism, you will describe the following characteristics and write your answer in this table. 1. Symmetry asymmetrical; radially symmetrical; bilaterally symmetrical 2. Tissue Organization tissues not clearly defined; different and distinct tissues 3. Body Cavities acoelomate; pseudocoelomate; coelomate 4. Openings to Digestive Tract one opening; two openings (mouth and anus) 5. Circulatory System open; closed 6. Habitat terrestrial; fresh water; marine; other (e.g. two or more) 7. Organs for Respiration body surface or skin; gills; lungs; other: e.g. spiracles, tracheae 8. Organs for Excretion skin; other (e.g. Malpighian Tubules; lateral excretory canals; lateral canals with flame cells; nephridia; kidneys) 9. Type of Locomotion sessile; float; swim; crawl; burrow; fly; walk; other 10. Support Systems hydroskeleton; endoskeleton; exoskeleton; cartilaginous skeleton; bony skeleton 11. Segmentation distinct segments; distinct body regions (e.g. head, thorax, abdomen); other 12. Appendages yes/no and how many; along entire length of animal; only on certain regions 13. Type of Nervous System nerve cord (one or two); sensory organs (which); signs of cephalization; brain; distinct head EXERCISE 19.1: Phylum Nematoda Roundworms (Ascaris) 1. Examine the anatomy of a roundworm (Ascaris). Draw a picture in the box below and label the following parts: anus, reproductive organs, digestive tract, lateral lines, cuticle, epidermis, muscle fibers, uterus, oviducts and ovaries.
Roundworm internal Dissection 3.e. How would nourishment be taken into the body and circulated to all of the cells? 3.g. Do you see any signs of segmentation pattern in the body wall or in the digestive, reproductive or excretory system? 3.h. Do you see any signs of a body support system? What do you think supports the worm s body? 4. Using the compound light microscope under low power, observe a slide of a cross-section through the body of a female roundworm. Draw a picture in the box below and use the picture below to help you to identify certain structures. Ascaris Cross Section
Can you detect muscle tissue adjacent to the endodermal layer? What do we call a coelem that is lined by mesoderm (outside) and endoderm (inside)? (see Figure 18.2b) 5. Can you see inside the uterus? If so, what can you see? Results 2. List some features of Ascaris that are possible adaptations to a parasitic lifestyle. Discussion 1. Discuss the significance of an animal having two separate openings to the digestive tract like Ascaris. 2. What are the advantages of a body cavity bring present in an animal?
EXERCISE 19.2: Phylum Arthropoda Lab Study A. Crayfish (Cambarus) 1. Obtain a preserved crayfish, study its external anatomy, and compare your observations with Figure 19.2 in your lab manual. Describe the following features: a. body symmetry - b. supportive structures c. appendages d. body segmentation - 2. Identify the three regions of the crayfish body: the head, thorax (fused with the head) and abdomen. Note the appendages associated with each region. Speculate about the functions of each of these groups of appendages. a. head appendages - b. thoracic (chest) appendages - c. abdominal appendages - 3. Feathery gills lie under the lateral extensions of a large, expanded exoskeletal plate called the carapace. What is the function of thee gills what are they for? 4.c. Is the circulatory system of the crayfish open or closed? 4.d. Given all of the organs and tissues around the digestive tract and inside the body wall in the body cavity, what kind of coelem do you think the crayfish has?
Lab Study B. Grasshopper (Romalea) 1. Obtain a preserved grasshopper, study its external anatomy, and compare your observations with Figures 19.4 and 19.5 in your lab manual. Note the following structures: head, thorax, abdomen, spiracles, tracheae, esophagus, crop, stomach, gastric pouches, intestine, rectum, rectum, anus, Malpighian tubules and ventral nerve cord. 2.a. What type of circulatory system does the grasshopper have (open or closed)? Discussion 1. Describe how each of the following external structures helps the grasshopper live successfully in a terrestrial environment: a. Exoskeleton b. Wings c. Large jointed legs d. Spiracles (what are these?) 2. Describe how each of the following internal structures helps the grasshopper live successfully in a terrestrial environment (what do they do?): a. Tracheae b. Malphigian tubules c. Rectum
EXERCISE 19.3: Phylum Echinodermata Sea Star 1. Obtain a preserved sea star, study its external anatomy, and compare your observations with Figure 19.6 in your lab manual. Note the following structures: aboral surface, oral surface, central disc, madreporite, endoskeleton, epidermis, mouth, tube feet, skin gills, stomach, gonads, digestive glands and ampullae. Discussion 1. Imagine you are a zoologist studying sea stars for the first time. What characteristics would you note from the dissection of an adult animal that might give you a clue to its phylogenetic relationships that it belongs to the deuterostomes rather than the protostomes? 2. What structures that you observe appear to be unique for echinoderms (use your text for reference)? 3. How would you continue your study to obtain more information that might help you in determining how to classify these animals within the Animal Kingdom? EXERCISE 19.4: Phylum Chordata Deuterostomes Lab Study A. Lancelets (Branchiostoma, formerly Amphioxus) 1. Obtain a preserved lancelet and place it in water on a watch glass. Use the stereoscopic dissecting microscope to observe the following: Locate the anterior end by the presence at that end of a nose-like rostrum extending over the mouth region. Notice the lack of a well defined head. Look for the segmented muscles. Do you see signs of a tail?
3. Now Observe the whole mount prepared slide of the lancelet and compare your observations with Figure 19.7 in the lab manual. a. Scan the entire length of the body wall. Do you see evidence of segmentation in the muscles? b. Look at the anterior end of the animal. Do you see any evidence of a sensory system? Describe what you do see: c. See if you can follow a tube from just under the rostrum into a large sac with numerous gill slits. This sac is the pharynx with gill slits which is one of the features that is unique for chordates. The extension of the body beyond the anus is called a postanal tail another of the features that is unique for chordates. Where is the anus located in these animals? Was a postanal tail present? d. Water entering the mouth passes through the gill slits and collects in a chamber called the atrium, just inside the body wall. The water ultimately passes out of the body at a ventral pore called the atripore. e. Now turn your attention to the dorsal side of the animal. Beginning at the surface of the body and moving inward, identify the following structures and speculate about their function (you should use your TEXT to assist you): dorsal fin nerve cord notochord The nerve cord is in the dorsal aspect of the lancelet. Have you seen only a dorsal located nerve cord in any of the previous animals studied? If so, which?
The notochord is a cartilaginous-like rod that lies ventral t the nerve cord and extends the length of the body. Have you observed a notochord in any of the previous animals studied? If so, which? 4. Identify the following structures and label them in the figure below: Segmented Muscles Dorsal Fin Nerve Cord Notochord Pharynx with Gill Slits Lab Study B. Fetal Pig (Sus scrofa) With your lab partner, read each of the questions on the table below. From observations you have made of other animals in these animal diversity laboratories, use your knowledge of vertebrate anatomy and your observations to answer the questions.
Question Response What type of symmetry do you observe? How many embryonic germ layers would be present? Are the cells organized into distinct tissues? How many digestive tract openings are there? Is the circulatory system open or closed? What is the habitat of this animal? What are the organs for respiration? What are the organs for excretion? What is the method of locomotion? Is the body support system internal or external? Does the body plan have distinct segments (regions)? Are there appendages present? What are they? What is the position and complexity of the nervous system?