Physical Geography

In “Geography 101,” we saw a list of different kinds of maps. Some were cultural or political. Others focused on the natural world, including geological, topographic, weather, and resource maps, as well as many thematic maps. Ironically, the list didn’t include one of my favorites, biogeographic maps.

Geologic Map of Texas
This geologic map of Texas contains clues about ancient seashores, dinosaurs, and Ice Age fossils.

We’ve already learned there are six continents and many thousands of islands surrounded by a global body of water that is divided into the Atlantic, Pacific, Indian, Arctic, and Southern oceans. Long ago, people believed the continents are fixed in place. In modern times, however, scientists discovered this isn’t true. Over periods of millions of years, the continents have repeatedly been joined with other continents and torn apart. Earth reveals itself as a living planet even before we even begin examining living things!

Geological maps are portals to prehistory. They can help us understand the geological features that express themselves as landforms, from mountains to valleys and canyons. They can even help us understand where the continents were located millions of years ago.

Topographic maps use contour lines to indicate elevation and landforms. With a topographic map, you can easily distinguish relatively flat areas like the Great Plains from more rugged upland areas.

You might think of a geological map as an X-ray of Earth, while a topographic map offers a view of its “skin,” or surface features. While the human body is supported by a vast network of blood vessels under the skin, water flows both above and below Earth’s surface. Hydrological charts show such hydrologic features as rivers and streams. Of course, Earth also has an atmosphere which is covered by weather maps.

Earth, water, and sky make up the lithosphere, hydrosphere, and atmosphere. a foundation for the star of the show, life. In fact, life makes up a fourth sphere, the biosphere.

The study of the lithosphere, hydrosphere, atmosphere, and biosphere is called physical geography. What are we waiting for? Let’s take a closer look at my favorite kind of geography, biogeography.

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