Fire and Life Intense heat smoke the crackling

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Fire and Life Intense heat, smoke, the crackling of burning grasses, the crashing of

Fire and Life Intense heat, smoke, the crackling of burning grasses, the crashing of flaming trees—all these characteristics of fire seem threatening. In recent years, forest fires have burned huge areas of forest and have endangered people and property nearby. But even though fire can be destructive, it can also be an agent of life. In fact, scientists are actively using fire to manage ecosystems—areas that contain specific groups of living and nonliving things. Prairies, forests, and woodlands are examples of ecosystems. The fear of fire has led people to limit fires that are a natural part of some ecosystems. Preventing or putting out smaller fires in a forest ecosystem can mean trouble. Occasional small fires burn small amounts of material and cause only limited damage. Without these smaller fires, burnable materials may build up and lead to the outbreak of a catastrophic fire.

An astonishing variety of plants blooms in this prairie in Missouri. The species of

An astonishing variety of plants blooms in this prairie in Missouri. The species of living things in some ecosystems have adaptations that allow them to thrive on fire. In western forests in the United States trees such as lodgepole pine and jack pine depend upon flames to release seeds from their cones. Cape lilies lying under the forest floor blossom almost immediately after a forest fire. On prairies, flowers such as the rare coastal gayfeather in Texas or the fringed prairie orchid in Illinois benefit from prairie fires.

On the left, seven months after a controlled burn, light shines on a new

On the left, seven months after a controlled burn, light shines on a new patch of wild hyacinth growing at the base of an oak tree. Observing Patterns Ecosystems include living things, such as plants and animals, and nonliving things, such as water and soil. Fires affect both the living and the nonliving. The photographs above show part of an oak woodland ecosystem. The photograph on the left shows a burn—a fire set deliberately by humans. The photograph on the right shows the same area seven months later. Ashes left from fires add nutrients to the soil. Fire also opens space on the forest floor. Areas that were shaded by small trees, plants, and dead branches receive light. Over time, wild hyacinth and other new plants grow around the oak, and new insects and animals

BRINGING BACK THE PRAIRIE At one time natural events, such as lightning, along with

BRINGING BACK THE PRAIRIE At one time natural events, such as lightning, along with human activity caused regular patterns of fire on the prairie. Bison grazed on tender young plants that grew up after fires, and the plants that weren't eaten by the bison had room to grow. In 1989, an organization called The Nature Conservancy turned the Chapman-Barnard Cattle Ranch in Northeast Oklahoma into the Tall Grass Prairie Restoration Preserve. Scientists at the preserve are using controlled fire and reintroducing bison to the area. Today there are more than 750 species of plants and animals growing in the preserve. In tall-grass prairie ecosystems, fire provides similar benefits. Fire burns away overgrown plants, enriches the soil, and clears the way for the growth of new plants. Bison prefer to graze on these new plants that appear after a fire.

A New Understanding Although some of the benefits provided by ecosystems can't be measured,

A New Understanding Although some of the benefits provided by ecosystems can't be measured, researchers are starting to measure the financial contributions of ecosystems. Ecosystems may help clean our water, balance gases in the atmosphere, and maintain temperature ranges. Researchers today are studying these benefits. In fact, a new frontier in ecology, called ecosystem services, is emerging. This new study is gaining the attention of both scientists and economists. Given our growing awareness of the importance of ecosystems, should humans deliberately set fire to areas in forests or prairies? The answer to this question requires an understanding of interactions among living and nonliving parts of ecosystems. Forest and prairie fires can be dangerous, but properly managed, they provide important benefits to society as well as to the natural world.

Ecosystems and Biomes

Ecosystems and Biomes

Ecosystems support life. Before, you learned • Living things need to obtain matter and

Ecosystems support life. Before, you learned • Living things need to obtain matter and energy from the environment • The Sun provides Earth with light and heat Now, you will learn • What factors define an ecosystem • About living factors in an ecosystem • About nonliving factors in an ecosystem VOCABULARY ecology, ecosystem, biotic factor, abiotic factor Four Square Diagram = Include: definition, example(s), picture, description, pronounce, origin, sentence, synonym, fun fact. Abiotic Factor

Living things depend on the environment. You wouldn't find a kangaroo in the Arctic

Living things depend on the environment. You wouldn't find a kangaroo in the Arctic and you won't see a polar bear in Australia. Each of these organisms is suited to a certain environment. The kangaroo and the polar bear are able to survive despite the harsh conditions of their surroundings. Ecology is the scientific study of how organisms interact with their environment and all the other organisms that live in that environment. Scientists use the word ecosystem to describe a particular environment and all the living things that are supported by it. An ecosystem can be as small as a pond or as large as a desert. What is important in an ecosystem is how the living parts of the ecosystem relate to the nonliving parts.

Let's take a look at a pond. A pond ecosystem is more than just

Let's take a look at a pond. A pond ecosystem is more than just water and fish. Plants grow in and around the water, and animals feed on these plants. A variety of tiny microorganisms in the water are food for fish and for each other. These are just a few of the living parts, or biotic factors (by-AHT-ihk), of a pond ecosystem. The nonliving parts, or abiotic factors (AY-by-AHTihk), include the air that supplies oxygen and carbon dioxide, the soil that provides nutrients, the water in the pond, and the sunlight that plants need to grow.

Biotic factors interact with an ecosystem. Living things depend upon an ecosystem for food,

Biotic factors interact with an ecosystem. Living things depend upon an ecosystem for food, air, and water, as well as other things they need for survival. In turn, living things have an impact on the ecosystem in which they live. Plants, as a biotic factor in land ecosystems, affect other biotic and abiotic parts of ecosystems. Plants are an important source of food. The types of plants found in a particular ecosystem will determine the types of animals that can live there. Plants can affect temperature by blocking sunlight. Plant roots hold soil in place. Even the atmosphere is affected by plants taking in carbon dioxide and releasing oxygen. Animals, as biotic factors, also affect an ecosystem. A beaver that builds a dam changes the flow of a river and so affects the surrounding landscape. Large herds of cattle can overgraze a grassland ecosystem and cause the soil to erode. In an ocean biome, corals form giant reefs that provide food and shelter for marine organisms.

Many abiotic factors affect ecosystems. Abiotic factors include both the physical and chemical parts

Many abiotic factors affect ecosystems. Abiotic factors include both the physical and chemical parts of an ecosystem. Physical factors are factors that you can see or feel, such as the temperature or the amount of water or sunlight. Important chemical factors include the minerals and compounds found in the soil and whether the ecosystem's water is fresh or salty. It is the combination of different abiotic factors that determines the types of organisms that an ecosystem will support. List four different abiotic factors that can affect an ecosystem. Tip: The word biotic means “living. ” The prefix a– in abiotic means “not, ” so abiotic means “not living. ”

1. 1 ECOLOGY - REVIEW QUESTIONS (PAGE 13) KEY CONCEPTS 1. Draw a diagram

1. 1 ECOLOGY - REVIEW QUESTIONS (PAGE 13) KEY CONCEPTS 1. Draw a diagram of an ecosystem near where you live. Label the factors “biotic” or “abiotic. ” 2. Give two examples of how plants and animals affect their environment. 3. Describe how temperature, light, and soil affect an ecosystem. CRITICAL THINKING 4. Predict Think of a forest ecosystem. Now imagine that a large volcanic eruption throws large amounts of dust and ash into the air, blocking out sunlight. How might the forest ecosystem be affected if the sunlight is blocked for a day? For a year? (If, then, because) CHALLENGE 5. Apply Think of how you fit into your local environment. List ways in which you interact with biotic and abiotic factors within your ecosystem.