Chapter 5 Lesson 2 What are Microorganisms?

Vocabulary Preview Microorganism: an organism that is too small to be seen with an unaided eye Microorganism: an organism that is too small to be seen with an unaided eye Bacteria: a certain type of microorganism Bacteria: a certain type of microorganism Mold: a kind of fungus Mold: a kind of fungus Protist: a one-celled organism that shares traits with plants or animals Protist: a one-celled organism that shares traits with plants or animals

Kinds of Microorganisms Microorganisms: are living things Microorganisms: are living things that are too small to see without a microscope. The environment contains The environment contains thousands of kinds of microorganisms. Most have only one cell. Most have only one cell.

You probably have some of this kind of bacteria, called staph, on your skin right now. Staph bacteria can cause annoying pimples or boils. They can also cause serious infections of the blood, bones, and lungs Strep bacteria can be a serious health threat. They cause illness in newborn babies. They can also harm pregnant women, children, older adults, and adults who have certain other illnesses.

Penicillin is a substance made by a mold. It kills harmful bacteria. First used during World War II, it prevented thousands of deaths from infection. The blue coloring in this cheese is actually mold. This mold, which is related to penicillin, is safe to eat

Bacteria Bacteria: is a microorganism. Bacteria: is a microorganism. Bacteria There are more bacteria on Earth than all other living things together. There are more bacteria on Earth than all other living things together.bacteria Bacteria may be shaped like rods, spirals, or balls. Bacteria may be shaped like rods, spirals, or balls. Bacteria

Mold Yeasts and molds are fungi that are microorganisms. Yeasts and molds are fungi that are microorganisms. Fungi look a little like plants, but they can’t make their own food. Fungi look a little like plants, but they can’t make their own food. Fungi are decomposers. Fungi are decomposers. They break down decaying plants and animals in the environment. They break down decaying plants and animals in the environment.

Protists Protists are also microorganisms. Protists are also microorganisms. Protists There are about 80,000 kinds of protists. There are about 80,000 kinds of protists. Some, like algae, make their own food. Some, like algae, make their own food. Others, such as protozoans, hunt for food like animals do. Others, such as protozoans, hunt for food like animals do. Protists can be single-celled or multi- celled. Protists can be single-celled or multi- celled.  Marine Protists Single-celled Protist

Microorganisms MicroorganismsMicroorganisms Microorganisms are everywhere! Microorganisms are everywhere! Certain bacteria in our digestive systems help break down the foods we eat. Certain bacteria in our digestive systems help break down the foods we eat. Without them, we could not use the nutrients in the food. Without them, we could not use the nutrients in the food. Without other microorganisms, we would have fewer foods to eat. Without other microorganisms, we would have fewer foods to eat. Bacteria turns milk into yogurt. Bacteria turns milk into yogurt. They also help produce certain kinds of cheese. They also help produce certain kinds of cheese. Yeast is a fungus that makes bread rise. Yeast is a fungus that makes bread rise.

Helpful Microorganisms Helpful Microorganisms Many more microorganisms help people that harm them! Many more microorganisms help people that harm them! Without phytoplankton in the ocean, we wouldn’t have enough oxygen to breathe. Without phytoplankton in the ocean, we wouldn’t have enough oxygen to breathe. Other microorganisms make important medicines such as penicillin. Other microorganisms make important medicines such as penicillin. These medicines kill bacteria that causes diseases. These medicines kill bacteria that causes diseases.

Plankton

Phytoplankton is made of bacteria and protists that live near the surface of the water. These organisms use photosynthesis to make their own food. They also release oxygen. Phytoplankton produces at least half of the oxygen in the air you breathe.

Helpful Microorganisms Helpful Microorganisms Some microorganisms remove harmful bacteria from wastewater at water treatment plants. Some microorganisms remove harmful bacteria from wastewater at water treatment plants. Others help clean up oil spills. Others help clean up oil spills. Phytoplankton is the main food for tiny fish, which are eaten by bigger fish. Phytoplankton is the main food for tiny fish, which are eaten by bigger fish. Without phytoplankton, there would be few fish that we could eat. Without phytoplankton, there would be few fish that we could eat.

Helpful Microorganisms Certain fungi help plants take in nutrients from the soil. Certain fungi help plants take in nutrients from the soil.fungi Without nutrients, the plants wouldn’t grow well, if at all. Without nutrients, the plants wouldn’t grow well, if at all. There would be fewer plants. There would be fewer plants. This would mean less food for people and other animals. This would mean less food for people and other animals.

Helpful Microorganisms Microorganisms cause dead things to decay. Microorganisms cause dead things to decay. Without them, Earth would be covered in dead plants and animals. Without them, Earth would be covered in dead plants and animals. We depend on microorganisms in all of these ways to survive. We depend on microorganisms in all of these ways to survive.

Harmful Microorganisms Harmful Microorganisms Some microorganism are harmful. Some microorganism are harmful. The bacteria in Salmonella and E.Coli can make you very sick. The bacteria in Salmonella and E.Coli can make you very sick. They grow on raw chicken and other meats, raw eggs, and other raw foods. They grow on raw chicken and other meats, raw eggs, and other raw foods. Cooking kills them. Cooking kills them. Harmful bacteria also grow on cooked food that is left out of the refrigerator for 2 hours or longer. Harmful bacteria also grow on cooked food that is left out of the refrigerator for 2 hours or longer. Salmonella

The organism that causes ringworm is a fungus, not a worm. Ringworm spreads easily and grows best on warm, moist skin. This kind of algae can suddenly “bloom,” or grow very quickly. People call this reddish water a red tide, though it has nothing to do with tides. Some algae in a red tide contain a poison that can kill fish.