Name Per Date. HANDOUT Worms

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1 UNIT 6 HANDOUT Worms Objectives: Observe the general characteristics of worms, explain how an worms is an animal, describe specialization in worms, describe the internal and external anatomy of segmented earthworm. Background Information Use the Animals book (pg 35-41) to gather background information about worms. Phyla of Worms Worms can be categorized into several phyla. Even though worms share several characteristics, taxonomists still separate them due the vast differences between each group. You will be learning about 3 phyla of worms, classified mostly by their shape. Name the phyla of each worm below. Common Name: Phylum: Flatworms Roundworms Segmented Worms Annelida We will be focusing our studies mostly on Platyhelminthes and Annelidas. (Hint: if you have trouble remembering the name for flatworms, just think platy means flat, as in platypus. ) Common Characteristics of Worms Although categorized into several separate phyla, worms still have a lot in common. For each box below, describe the common characteristics of worms. Category Description Backbone Cellular Organization Hint: cells, tissues... Nervous System Reproduction Sexual: Asexual: Note, the text mentions some worms are both male and female. These worms are called hermaphrodites. Unit 6 Worms PAGE 1

2 Flatworms Fill in the table below with information about flatworms. Category Description Examples Appearance Source of food Planaria Planarians are an example of flatworms. However, they are not parasites. Instead, planarians are, feeding on or material. Planarians also have some interesting anatomy. On their head they have two which are used to detect light and move away from it. Odd, eh? Planarians rely mainly on to locate food. How planarians feed, in Mr. Ower s professional opinion, is the most disturbing, yet, cool spectacle you can ever watch. (You ll get to see it, don t worry.) Read the last paragraph in the planarians section. Go ahead, this packet will wait for you. Ah, done? Disturbing no? Okay, summarize what you read in the that paragraph. How do planarians eat? FYI, the digestive system of a planarian is called a two-way system. Everything comes and goes through one opening. Therefore, everything moves in two directions: either in or out. They don t have an anus to remove waste. Waste is removed the same way food is taken in. See what I mean? Disturbingly cool. Okay, time to watch it! See Mr. Ower and he ll show you a video of the planarians feeding. Don t worry, it s only feeding...not waste removing. After watching the video, obtain a planarian from Mr. Ower. Observe its movements and draw a picture of it on the next page. Get ready to do some labeling. Unit 6 Worms PAGE 2

3 1. Observe the movement of the planaria. Describe how it moves. Hint: which part always moves first? Does it move like a snake? Where does it like to stay? 2. Draw a picture of your planarian. Label the following parts: head (anterior end), eye spots, rear end (posterior). Hint: draw it from overhead so it resembles what you see in your textbook on pg. 38. Return your planarian to Mr. Ower. Before moving on, I want you to think of how a planarian is like an animal. Remember, all animals have similar characteristics. For each characteristic listed below, provide information about the planarian that describes how it is an animal. This part you won t find word-for-word in the book. You need to apply the information you read to answer the section below. Heterotroph: Complex body systems: Adaptations for survival (see handout 76 for types/examples of adpatations) Roundworms Fill in the table below with information from the book. Category Description Appearance Source of food Digestive system Unit 6 Worms PAGE 3

4 Roundworms are highly adapted to eating food. What advantage does the roundworm s digestive system provide it? Segmented Worms - External Anatomy Obtain the following supplies from Mr. Ower 1 - Dissecting Tray with materials 1 - Dissecting mat 1 - Scalpel + blade 10 - T-pins 2 - Dissecting Needles 1 - glove/person 1 - Plastic bag 1 - forceps 1 - scissor 1 - segmented earthworm. 2 - pairs of goggles Safety note: dissecting tools (scalpel, t-pins, scissors, needles) are very sharp. Extreme caution must be used while working with these tools. Follow the procedure below for observing the earth worm. Use your dissecting manual (DM) to assist you. Some information will be in the Animals book, others will be from Mr. Ower s dissection demonstration. 1. Label your bag with your names and your period number. 2. Remove all materials from your tray except for your earthworm. Do not touch these materials unless told to do so. Keep the materials in a safe place. 3. Put on your glove on your non dominant hand (goggles are optional at this point). 4. Observe the exterior of the worm. You will notice a dark side and a light side. The dark side is the back side of the worm and is referred to as the.the light side is referred to as the. 5. Observe the front of the worm. This is front is the called the (DM, 1) end and is where you can find the mouth of the worm. Observe the anterior end again. You will notice a small flap of flesh covering the mouth. This is called the. Note: this section is not considered a segment. Move along the length of the worm noticing its many segments. Each segment is separated by. Almost all of the segments have two pairs of (Animals, 40, diagram) that are on its surface. These are used for (Animals, 41). 6. Almost all of the segments appear identical except for one. You should notice a large segment near the anterior end of the worm. It is often lighter in color. This segment is called the (DM, 1, diagram). This part is used in (DM, 1). Unit 6 Worms PAGE 4

5 7. Near the clitellum and on the ventral side of the worm, you should notice some small openings. These openings are used in reproduction. 8. Continue examining the length of the worm until you come to the hind end. This hind end is called the (DM, 1) where you will find the, or where waste comes out of the organism. Segmented Worms - Internal Anatomy Do not start this section until Mr. Ower has taught you how to dissect the worm! 1. Remove all materials from your tray except for your earthworm. Do not touch these materials unless told to do so. Keep the materials in a safe place. 2. Put on your gloves and goggles (not optional!) 3. Secure your worm to the dissecting tray as instructed during the demonstration. Follow the instructions for opening the worm (use notes and dissection guide). After exposing the internal organs, identify each one and learn its function (start this by continuing to step 4 below.) 4. Observe the worm at the anterior end. You should notice a fold in the first segment. This is the, the spot where food enters the organism. 5. Directly after you will find the pharynx. The function (job) of the pharynx is to 6. Continuing posteriorly you will pass over the, a tube that connects the pharynx to the. 7. The crop will be found at the end of the esophagus. It s function is to 8. After food leaves the crop, it is passed to the where the food is 9. After the food leaves the gizzard, it is passed on to the where. 10.Finally, the waste leaves the worm at the posterior end through an opening called the. 11. (Animals, 40) The worm has a circulatory system. This means that blood travels through blood to and from the heart. The advantage of a closed circulatory system is that the worm can be and more than organisms with an open circulatory system. You should be able to observe a total of hearts in the organism. Note: this can be difficult since many students cut through the hearts while dissecting. You can count them in the diagram on page 40 if you cut through them. Unit 6 Worms PAGE 5

6 12.Also in the worm is a simple nervous system. The brain is found at the end of the worm. Along the length of the worm is the central nervous cord which allows the worm to transmit signals from the brain. 13.Place the dissected worm and any tissue or detritus into the bag. Clean your tray and dissecting materials as directed by Mr. Ower. Return all cleaned and dry supplies and the bagged worm to Mr. Ower. Segmented Worm - Diagram Label the parts of the diagram below. Only do the lettered parts. Use the word box below to help you! Anus Brain Clitellum Crop Esophagus Intestine Gizzard Hearts Mouth Pharynx Segments C A B D E Do not label G F H I J K Do not label Do not label a. g. b. h. c. i. d. j. e. k. f. Unit 6 Worms PAGE 6

Chapter 12 Part 2. The Worms Platyhelminthes, Nematoda & Annelida

Chapter 12 Part 2. The Worms Platyhelminthes, Nematoda & Annelida Chapter 12 Part 2 The Worms Platyhelminthes, Nematoda & Annelida Phylum: Platyhelminthes Examples: Flatworms, Planaria sp., tapeworms and blood flukes Acoelomate, Invertebrate, Simplest critter w/ bilateral