Out of Sight Don’t worry. Not everything in the micro


world is trying to bite you. Some micro beasts want nothing to do with you. T ey are more interested in plants. Take the gall mite, for example. It’s a plant


parasite. It latches on to a plant to feed and lay its eggs. T is forms a small bump, or gall. Lots of mites on a plant can cause lots of galls. Other wee critters live below you. T ey’re


in the soil. Armies of microscopic creatures live there. T ey’re called nematodes. T ere are many kinds of nematodes. Most look like tiny worms. Several million of them can live in a square meter of soil. Some nematodes churn up the soil and


make it richer. Some nibble on plant roots. T ey pierce the root cells and suck out the contents. Others eat rotting plants or dead animals that they find in the dirt. Some kinds of nematodes eat meat. T ey


attack bugs. T ey enter a bug while it is still alive. T ey multiply inside their bug host. T ey get energy from the host until it dies. T en they leave the dead bug to look for a new host.


Micro Mysteries Micro animals may be small, but scientists


know a lot about them. T ey even know about some of the critters’ mysterious ways. T e water bear is a good example. Water


bears are short and plump. T ey live in the water and eat plants. T ey are also some of the toughest creatures on Earth. You can freeze them to -273° Celsius


(-459° Fahrenheit), and they live. Heat them to 151°C (304°F), and they’re fine. Blast them with radiation, and they just keep going. And that’s not all. T ey can live in the vacuum of space and for 10 years out of the water. Scientists know all these things about the


water bear. What they don’t know is how or why the water bear is so tough. Water bears aren’t the only microscopic


mystery for scientists. T ere’s another creature that you’re not likely to meet in person. It’s a type of worm. T is worm can be found near volcanoes on


the ocean floor. It lives in near total darkness. T e water around it is almost boiling. Toxic chemicals are all around it. Scientists don’t know how it survives there. Yet millions do.


Micro Universe You’ll find micro critters deep in the


ocean. You’ll find them on the tips of your eyelashes. You’ll find them almost everywhere in between, too. Just because you can’t see them doesn’t mean they’re not there. Some of these microbes can


cause big problems for hosts. Many help their hosts. Some need no host at all. Two things are certain. Our planet wouldn’t be the same without them, and we need many of them to live.


This micro creature digs into the soil.


22 NATIONAL GEOGRAPHIC EXPLORER


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