1. SINGLE-CELLED ORGANISMS

2. WHAT IS A SINGLE-CELLED ORGANISM? AN ORGANISM WHERE ALL THE LIFE PROCESSES ARE CARRIED OUT IN A SINGLE-CELL. BACTERIA ARE THE MOST NUMEROUS SINGLE-CELLED ORGANISMS ALL OTHER LIFE ON EARTH DEPENDS ON BACTERIA AND OTHER SINGLE-CELLED ORGANISMS TO SERVE AS FOOD, BREAK DOWN WASTES, AND PROVIDE OXYGEN SINGLE-CELLED ORGANISMS CAN BE HARMFUL AND BENEFICIAL

3. NEEDS OF ALL LIVING THINGS: TAKE IN FOOD AND GET RID OF WASTES. DIGEST NUTRIENTS SO THEY CAN USE AND STORE ENERGY. GROW AND REPRODUCE SINGLE-CELLED ORGANISMS DO ALL OF THESE THINGS IN ONE CELL! SINGLE-CELLED ORGANISMS ARE LIVING THINGS!

4. SINGLE-CELLED ORGANISMS CAN ONLY BE SEEN THROUGH A MICROSCOPE.

5. DIATOMS DIATOMS ARE EXAMPLES OF ONE CELLED ORGANISMS. DIATOMS ARE CLASSIFIED AS PROTISTS, A LARGE AND DIVERSE GROUP. FISH, WHALES AND OTHER ORGANISMS THAT LIVE IN THE WATER EAT DIATOMS. WHEN DIATOMS DIE, THEY DO NOT BREAK DOWN, INSTEAD THEY FORM SOFT, CHALKY MATERIAL. DEPOSITS OF THIS MATERIAL ARE FOUND ALL OVER THE WORLD AND ARE USED IN CLEANING PRODUCTS, EXPLOSIVES. MOST OF THE WORLD'S PETROLEUM COMES FROM DIATOMS.

6. BACTERIA BACTERIA IS A SINGLE-CELLED ORGANISM THAT HAS A VERY IMPORTANT JOB! BACTERIA BREAKS DOWN THE REMAINS OF DEAD PLANTS AND ANIMALS AND RETURNS THE MATERIALS FROM THE D DEAD ORGANISM BACK TO THE GROUND. BACTERIA HELPS PROCESS SOME OF THE FOOD YOU EACH SUCH AS YOGURT, SOUR CREAM, CHEESE, AND PICKLES. BACTERIA ALSO LIVES INSIDE OF YOU! YOUR BODY NEEDS BACTERIA TO DIGEST FOOD PROPERLY AND TO MAKE VITAMINS!

7. ALGAE ALGAE IS ANOTHER SINGLE-CELLED ORGANISM LIKE PLANT CELLS, ALGAE CAN MAKE THEIR OWN FOOD USING ENERGY FROM THE SUN. IN THE PROCESS, THEY GIVE OFF OXYGEN. MUCH OF THE OXYGEN IN THE AIR COMES FROM THE ALGAE IN THE OCEAN. ALGAE IS ALSO FOOD SOURCE FOR MANY ANIMALS.

8. YEAST YEAST IS ANOTHER SINGLE-CELLED ORGANISM YEAST IS USED TO MAKE BREAD, VINEGAR, AND ETHANOL. ETHANOL IS AN IMPORTANT GASOLINE ADDITIVE. A FEW TYPES OF YEAST CAUSE DISEASES IN PLANTS, ANIMALS AND HUMANS.

9. HOW DO SINGLE-CELLED ORGANISMS GET FOOD? SINGLE-CELLED ORGANISMS MUST MOVE TO GET THEIR FOOD (EXCEPT FOR ALGAE, BUT IT MOVES AS WELL). THERE ARE MANY DIFFERENT WAYS FOR SINGLE-CELLED ORGANISMS TO MOVE. 1. ONE WAY IS TO STRETCH IT'S OUTER MEMBRANE INTO ARMS WHICH SURROUNDS THE FOOD AND FORMS A SAC (VACUOLE) AROUND THE FOOD, WHICH IS THEN ABSORBED INTO THE CYTOPLASM. 2. ANOTHER WAY IS A FUNNEL CALLED AN ORAL GROOVE. CILIA (SMALL HAIRS) MOVE BACK AND FORTH, SWEEPING FOOD PARTICLES INSIDE THE CELL. A VACUOLE FORMS TO CARRY THE FOOD THROUGHOUT THE CELL.