Ebook Fundamentals of physical geography: Part 2

Part 2 book "Fundamentals of physical geography" includes content: Biogeography and soils; earth materials and plate tectonics; volcanic and tectonic processes and landforms; weathering and mass wasting; water resources and karst landforms; fluvial processes and landforms; arid region landforms and eolian systems; glacial systems and landforms, coastal processes and landforms.
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Ebook Fundamentals of physical geography: Part 2 Biogeography and Soils 9 :: Outline Ecosystems Succession and Climax Communities Environmental Controls Soils and Soil Development Factors Affecting Soil Formation Soil-Forming Regimes and Classification Ecosystems and Soils: Critical Natural Resources The living environment at the surface and the soils below are interdependent and intricately linked—the characteristics of one influences the characteristics of the other. Natural Resources Conservation Service 209 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. 210 CHAPTER 9 • BIOGEOGRAPHY AND SOILS :: Objectives When you complete this chapter you should be able to: ■ Describe the major components of a soil and how they vary to pro- ■ Define the four major components of an ecosystem, and explain their duce different soil types. interdependence. ■ Discuss the role of water in soil processes and how different ■ Recognize that other environmental controls may be more important amounts of available soil water can affect the vegetation growing on a local scale, but that climate has the greatest influence over eco- on a soil. systems on a worldwide basis. ■ Understand the factors that determine a soil’s formation, develop- ■ Explain how vegetation becomes established on barren or devastated ment, and fertility, including the role of vegetation. areas, and cite an example of the steps in plant succession. ■ Explain why soils are among the world’s most critical resources, and ■ Provide examples of how plants, animals, and the environments in the need for effective soil conservation practices. which they live are interdependent, each affecting the others. ■ Cite a few reasons why humans affect ecosystems and soils more ■ Outline the climatic factors that have the greatest effect on plants than all other life forms, and some examples of major impacts. and animals, and summarize the nature of those climatic impacts. Biogeography is the study of how environmental factors affect nature, they are usually closely related to nearby ecosystems the locations, distributions, and life processes of plants and and integrated with the larger ecosystems of which they are a animals. Basically, this discipline seeks explanations for the part. The ecosystem concept is a valuable model for examining geography of life forms. Biogeographers delineate the spatial the structure and function of life on Earth. boundaries of ecosystems, and investigate how and why envi- ronmental characteristics change spatially and over time. Soils are intimately related to the factors that also influence the Major Components biogeography of an area. The characteristics of a soil reflect the Despite their great variety on Earth, the typical ecosystem has interactions among the climate, vegetation, rocks, minerals, four basic components (■ Fig. 9.2). The first of these is the and fauna at its location. Soils are also environments that teem nonliving, or abiotic, part of the system. This is the physical with organisms living on and beneath the surface. Relation- environment in which the plants and animals of the system ships and interactions among the different climate regions, live. In a terrestrial ecosystem, the abiotic component their associated vegetative biomes, and certain soils were in- provides life-supporting elements and compounds in the soil, troduced in Chapters 7 and 8. In this chapter, we take a closer groundwater, and atmosphere. look at biogeography and at the nature of soils. The second component of an ecosystem consists of the basic producers, or autotrophs (meaning “self-nourished”). Plants are important autotrophs, because they can use solar Ecosystems The term ecosystem refers to a community of ■ FIGURE 9.1 This mountain ecosystem in Utah demonstrates the close organisms that occupy a given area, and the relationship between living organisms and their nonliving environment. interdependent relationships—with each other Why might it be difficult for a biogeographer to determine boundaries for this and the environment—that allow the organisms ecosystem? to thrive (■ Fig. 9.1). Generally, ecosystems are studied on a local or regional basis, but the en- tire Earth system (the ecosphere) also functions as an ecosystem. When farmers plant crops, spread fertilizer, control weeds, and spray ...