We coexist with a variety of other organisms that affect our lives in significant ways. This area deals with how animals, plants and diverse microorganisms such as fungi, viruses and bacteria affect our lives and how we benefit from them. By studying this area, students become aware of the intimate relationships between humans and other organisms. Students recognize the positive and negative impacts on humans of microorganisms, animals and plants. They also learn how advances in life sciences are helping humans to benefit from different types of organisms.
The grade 6 English science unit, Organisms and Our Lives, meets the academic content standards set in the Korean curriculum, which state students should: a) Understand the characteristics of organisms such as mushrooms, mold, pond scum and paramecia and the environments in which they live. b) Understand both the positive and negative impacts on humans created by a variety of organisms. c) Find examples of how advanced life science can be applied in everyday life.
Healthy pond water is usually home to many microorganisms. A microorganism is any organism that is too small to see without the use of a microscope. A common example is a single-cell microorganism called protozoa. Amoeba proteus is a type of protozoa found in pond water. These microorganisms eat algae or other smaller protozoa by surrounding it with its body. The enzymes in the Amoeba proteus dissolve the food to give it energy. Protozoa are important as they are the food supply of many insects. Many insects are attracted to ponds. They lay their eggs in and around ponds. Pond water Bucket Pipette Slide Microscope Amoeba proteus. 1. Collect some pond water in a bucket. 2. Use a pipette to put a small amount on a slide. 3. Use a microscope to observe the slide. Draw pictures of some of the microorganisms you saw. 1. What is a microorganism? 2. Why are protozoa important? 1
The soil around your school and garden often has many little organisms living in it. Many of these creatures are known as decomposers. These organisms help to decompose or rot dead pieces of plants, such as leaves and also other dead organisms. As the decomposers do this, they are turning these things into nutrients that plants need to grow. Rubber gloves Soil Trowel Magnifying glass Plastic bag Pencil Some animals, such as worms, break up the soil and help get air into it. They mix the soil and allow important minerals to get to the plants. Their burrows also allow water to travel to the roots of the plants. 1. Use the trowel to collect a soil sample. Put it into a plastic bag. 2. Use a pencil to break the soil apart and look for small organisms. 3. Look through the magnifying glass at any small organism you find. Draw pictures showing the organisms you found in the soil. 1. Why are decomposers important? 2. What is one thing a worm does that is useful? 2
Mushrooms look like plants, but they are neither plants nor animals. They are an organism known as fungi. They can be found on dead wood, which is where they get their food from. You can eat some mushrooms, but other mushrooms are very poisonous. You should never eat a mushroom that you found outside unless it has been identified as safe by an expert. Mushrooms have a stem that lead to a cap. On the underside of the cap are its gills. This is where the mushroom makes its microscopic spores that will be carried away by the wind to allow new mushrooms to grow. Mushroom kit Spray bottle Water Magnifying glass The gills of the Lactarius indigo. 1. Follow the instructions on the mushroom growing kit. 2. Keep the wood wet by spraying it with water two times a day. 3. After a week, use a magnifying glass to observe the structure of the mushroom. Draw a picture showing the stem, cap and gills of the mushroom you grew. 1. What type of organism is a mushroom? 2. Plants make seeds to grow new plants. How does a mushroom make new ones? 3
Mushrooms are just one example of a fungus. Another example is wood-decaying fungus. This is a type of fungus that digests moist wood and makes it rot. A type of wood-decaying fungus is known as white rot which breaks down different parts of the dead wood and makes it feel moist, soft, spongy, or stringy and appear white or yellow. Humus Beetle larva Container Cup or mist sprayer Water Some beetles, such as the rainbow stag beetle, lay their eggs in soft, rotting wood found on the forest floors. This is because the larvae of these beetles eat this wood and the fungus that is helping to rot the wood. Rainbow stag beetle 1. Fill a container with humus. 2. Add some water to make the humus moist. Don t saturate the humus with too much water. 3. Add the larva to the humus. Keep the humus moist by spraying it with water on a weekly basis. Draw a picture showing the interaction between the larva and the fungus. 1. What is white rot an example of? 2. Why do some beetles lay their eggs in rotting wood? 4
Bacteria can be found almost everywhere. They are small microorganisms. Some are useful and help to prevent diseases. Other bacteria can make you very sick and can cause infections. There a billions of bacteria on your skin. These bacteria are looking for a way to get into your body so that they have a warm place to live and lots of food. This is why you should always wash your hands before eating food. This is also the reason you should wash cuts with soap and water. The bacteria will try to enter your body through your mouth and the cuts and your body. If the bacteria are kept out of your body, they are pretty harmless. Petri dishes Agar solution Cotton swabs Ziploc bags A type of bacteria; Escherichia coli 1. Make an agar solution and wait until it hardens. 2. Use a cotton swab and roll it over something you want to test for bacteria. 3. Lightly draw a squiggly line in the agar with your cotton swab. Put the petri dish in a Ziploc bag and leave it in a dark place. Draw a picture showing what your petri dish looked like after bacteria started growing. 1. Are all bacteria bad? Please explain. 2. Why do bacteria want to get into your body? 5
Anything that stops your body working properly is called a disease and is often caused by germs. Bacteria and viruses are two types of germs that make people sick. Germs are infectious, which means they can be passed on from one person to another. They can also be passed on by animals. These germs can be spread through air and water and by touch. Your body defends itself against germs. Your skin keeps out many germs. However, they can enter your body when you put your hands in your mouth. It is important to wash your hands before eating and to make sure that you wash them well. Glo Germ Gel Black light Cocci Bacilli Vibrios Sphirilla Types of bacteria. 1. Pump a squirt of the Glo Germ Gel in your hand. Rub your hands together to so that it covers both the front and back of the hands. 2. Turn on the black light to see how your hands look. 3. Wash your hands as you would normally. Turn on the black light to see what your hands look like. Draw a picture showing the areas of your hands that you didn t clean so well. 1. What are two types of germs that can make you sick? 2. How can germs be passed on? 6
Mold is a fungus. It is a type of decomposer. This means that it breaks down dead animals and plants. If you keep food in your fridge for too long, you might see mold growing on it. This mold is starting to break down the food. This is why the food changes color and begins to smell bad. The green, fuzzy mold that grows on food is the same mold that scientists use to make penicillin. This is the medicine that fights bad bacteria when people get sick. However, in the state that the mold is found on decomposing food, it can cause people to have allergic reactions. You should never touch or breathe it in. Lemon Ziploc bag Pipette Water Magnifying glass Moldy orange 1. Put the lemon in a Ziploc bag and add a few drops of water. 2. Completely close the Ziploc bag and put it in a dark place for a week. 3. Take out the lemon, but do not touch or breathe in the mold. Look at the mold through a magnifying glass. Draw a picture of your moldy lemon. 1. What does mold do? 2. What is penicillin? 7
Yeasts are living, single-celled, plantlike organisms. They are so small they can only be seen using a microscope. They belong to the fungus family, like molds and mushrooms. Yeasts do not have chlorophyll, so they are unable to use the sun to make their own food like other plants. Instead, yeasts feed on the sugars in other organisms and plants to survive. As the yeast eats this sugar, it makes alcohol and carbon dioxide gas. There are many types of yeasts, but one type is used to make bread. The carbon dioxide gas it makes helps to make bread rise and the alcohol it makes helps to give bread its taste and smell. 2 packs of yeast 2 glasses Whiteboard marker Sugar Cling wrap 2 elastic bands Yeast cells under a microscope. 1. Half fill two glasses with warm water and stir a packet of dry yeast into each cup. Draw a line on each cup to show the level. 2. Add a teaspoon of sugar to one cup and stir it. 3. Cover each cup with cling wrap and keep it in place with an elastic band. Wait for 20 minutes. Draw a picture of the two cups after 20 minutes passes. 1. What are yeasts? 2. What does yeast make when it feeds on sugar? 8