46 Habitats and the Environment-High

Habitats and the Environment Written by Kira Freed

Introduction Can you imagine a wild polar bear living in Hawaii? How about a palm tree growing in Antarctica? You probably know that these things would never happen, but do you know why not? A habitat is a place where a living thing lives. But it is not just a home. A habitat provides a living thing with the food, water, air, and shelter it needs to survive. It has many parts that all work together. In this book, you will learn about what makes up a habitat and how habitats are different for different living things. By the time you finish reading, you will know why the pictures on this page could not be real.

The Building Blocks of Habitats Earth has many types of habitats. What causes one habitat to be different from another habitat? To answer this question, let's explore the building blocks of habitats. The first building block is latitude. Latitude is a measure of how far a place is from Earth's equator, or middle. The lines that go left to right across a globe show different latitudes. As Earth spins, the Sun's energy warms parts of the planet differently. The latitudes closer to the equator are warmed more than the polar regions, which are far from the equator.

In each band of latitude, some land is higher than other land. Elevation— how high or low an area is— is the second building block of a habitat. Areas of low elevation are warmed more by the Sun's energy than areas of high elevation, which are cooler. Why is that? The layer of air around Earth is the atmosphere. Think of the atmosphere as a blanket of air. Even something as light as air still has weight and thickness (or density). Close to the ground, the blanket is thick— there is lots of air above it, pressing down— so it holds in more heat. High in the mountains, the blanket of air is thinner. More heat escapes, so it is colder. Do You Know? You might wonder why areas of high elevation aren't warmer than areas of low elevation, since it seems as if they're closer to the Sun. The Sun is incredibly far away— about 150 million kilometers (93 million miles) from Earth. The height of Mount Everest (8,848 meters or 29,028 feet) is a tiny fraction (about .00006) of the distance from Earth to the Sun. That's too small to make a difference in the amount of sunlight it gets.

Because some areas are warmer than others, the differences in temperatures create wind. The wind carries moisture (water) between parts of the system. The combination of differences in temperature, wind, and moisture creates vastly different climates all over our planet. Climate is weather patterns over long periods of time— not just days, weeks, or months. Climate is half of the third building block of habitats.

The other half of the third building block of habitats is land and water features. Almost three-fourths of Earth's surface is water, and almost all of that is in oceans. Earth's land, the other quarter of Earth's surface, is different from place to place. It may be flat, hilly, or mountainous. There may be big lakes, small streams, or very little surface water. Land and water features are as important as climate in building a habitat.