Presentation on theme: "They’re squiggly... They’re wiggly… They’re Earthworms! An Introduction to Earthworms."— Presentation transcript:
They’re squiggly... They’re wiggly… They’re Earthworms! An Introduction to Earthworms
Hello Fourth Graders! My name is Ernie the Earthworm, how do you do? Today I am going to tell you all that you’ve ever wanted to know about earthworms, and much more! Oh, and if you are wondering who those two little critters are at the bottom left, those are my friends Eddie and Eli. They are here to enjoy the slideshow too! Let’s Go!
What are Earthworms? Good question! Earthworms are called annelids. Annelids are a group that have long, soft bodies that are segmented, or that have many parts. These parts, or segments, look like a bunch of little rings. The scientific name for these rings is annuli. Earthworms are also invertebrates. That means that they have no backbone. Actually, earthworms have no bones at all! Can you think of another animal or mammal that does not have a backbone? There are about 2,700 different kinds, or species of earthworms! Wow, that’s a lot!
This is my friend Edith. Do you notice all of those rings?
An Earthworm’s Body Earthworms are usually reddish or reddish brown. The average earthworm is about inches long. As I said earlier, our bodies are soft, and they are also quite flexible. I can even tie myself into a knot! Nah, I don’t want to do it right now…. Earthworms usually have between 100 and 200 annuli, or segments. Something that these segments help us to do is regenerate! Do you know what that means? We also have 5, that’s right 5, hearts, and a brain that’s located at the front of the body. Our mouths and our bottoms are located at our front and back ends. Next, my friend Herman will tell you a bit more about an earthworm’s body.
Hi Herman!! Hi Ernie! Hey kids! I would like to tell you a bit about the part of our earthworm body called the clitellum. When I am a few weeks old, you will notice a light- colored band forming near my front end. This is my clitellum. My clitellum will someday help to form cocoons. New baby worms will hatch from the cocoons and I will have a family.
Yup, Earthworms have hair! If you had a microscope and looked really, really closely at each segment, you will see something that looks like a bunch of small hairs or bristles. (And I'll bet you thought worms were bald.) These bristles are called setae (pronounced see-tee) and they help me move. I have four pairs of these bristly hairs on each ring or segment. Thanks Herman!
What do Earthworms eat? You kids have great questions! Earthworms have very small mouths, so we can only eat very tiny things like bacteria and fungi, which you couldn't see unless you are looking through a microscope. We also eat organic matter like plants (mmmm, salad) and decaying animals from soil. I guess that sounds sort of gross! Sometimes the bits of food are too big for my mouth, so I moisten them to make them soft and suck them right into my mouth. (Don't try this at home, human parents tend not to like this.)
How do Earthworms eat? Since I have no teeth, I cannot really chew my food like you do. I do have something inside of me close to my mouth called a gizzard. You might have heard this word before because birds, including chickens and turkeys, have a gizzard almost like mine. As I eat my food, some grains of sand and soil get into my gizzard. These grains of sand and soil push against each other, mix with moisture and grind the food into tiny pieces (kind of like my own personal food processor). When the food leaves my gizzard, it goes into my intestine. The food is dissolved there and absorbed into my blood. Then it is carried to all parts of my body to keep me strong, healthy and slimy.
After our bodies have used up whatever they need, we go to the bathroom in the soil. Our waste is called casting. You may think that this is too much yucky information for you, but earthworms’ castings help fertilize soil. Think about it this way…If there are 500,000 worms living in an acre of soil, we could make 50 tons of castings. That's like lining up 100,000 one pound coffee cans filled with castings. Having worms around in your garden is a real good sign that you have a healthy soil.
Other ways Earthworms Help the soil…. The earthworm is one of nature's top "soil scientists.“ We have also been called “nature’s plows” because we are like free farm help. When we move through the soil, we help to “turn” the soil. That means that we bring down organic matter from the top of the soil, and we mix it with the soil below. Quite helpful if I do say so myself! We worms also help to increase the amount of air and water that gets into the soil. We break down organic matter, like leaves and grass into things that plants can use.
How do Earthworms move? Earthworms have two sets of muscles: circular muscles, which move around each segment, and long muscles, which run through the length of the body. Actually, I'm pretty well-built, if I do say so myself. When my circular muscles tighten up, my body becomes thinner and longer. This movement by my circular muscles squeezes my front end forward. My other long muscles squeeze together and help move the rear end of my body towards the front end, making me look short and thick. So, this is how I move forwards and backwards. My setae act like the brakes on a car, helping me to slow down or stop. Pretty cool, huh? Next, Herman and his assistant will show you how it’s done! Long and thin Ernie… Short and thick Ernie
Nice Job! Very Good!
How do Earthworms breathe? Worms do not have lungs but I breathe through my skin. I take in oxygen through my skin and it goes right into my bloodstream. My skin must stay wet in order for the oxygen to pass through it, but if I am in too much water I will drown. Just keep me damp, moist and slimy. Although if the water has lots of air in it, I can stay under for a long time. Right, Herman? You are correct, my friend!
How are baby Earthworms born? Remember the clitellum? Well, the clitellum holds both male and female reproductive parts, which means that earthworms are neither male nor female; we are both. We need to mate with other earthworms, and while we are mating, we form a cocoon on one of our clitellums. The cocoons are much smaller than a grain of rice and are yellow-colored. Each cocoon can have 1-5 worms. If conditions are not right for hatching, such as dryness, my cocoons can be dormant, which means they do not hatch. If the conditions are right, our babies will be born in 2- 3 weeks! They are practically see-through, but I think they are so cute! After about 6 weeks, the babies are old enough to produce their own babies, and the cycle starts all over again!
Where do Earthworms live? Earthworms live underground in the soil. Since we earthworms need to live in a warm, dark, and moist environment, we would not survive anywhere else. We earthworms create burrows in the soil. A burrow is a hole or tunnel underground. In order to dig our burrows, we eat the soil, and get rid of, or excrete, waste as we move along. How deep we dig our burrows depends on how moist the soil is. If the soil is drier towards the top of the soil, we will move deeper. That’s why when it rains, you may see a lot of my friends at the surface!
Bob, come on home for dinner! Coming mom! I just need to get off of this curb and into the soil, and I’ll be right there!
Earthworm’s Enemies I know it’s hard to believe, but worms have enemies. Of course, they are not real enemies. I am sure they are quite nice, but they need to eat to survive as well. Some animals that I need to watch out for are shrews, moles, hedgehogs, and birds.
Some cool, wormy, fun facts… Did you know that… In one acre of land, there can be more than a million earthworms. The largest earthworm ever found was in South Africa and measured 22 feet from its nose to the tip of its tail. Even though worms don’t have eyes, they can sense light, especially at their front end. They move away from light and will become paralyzed if exposed to light for too long (about 1 hour). Worms can grow a new tail, but not grow a new head if they are cut off. Charles Darwin spent 39 years studying earthworms more than 100 years ago. Worms can eat their weight each day.
Large Worms! Wow! They are huge!
Herman had to leave early. He says goodbye and thanks for listening. We hope that you enjoyed learning all about your slimy friends. Take care of your classroom worms, and remember: observe, think, learn, and have fun! Goodbye fourth graders! Herman the worm and facts: