Prologue
Introducing Physical Geography
The study of Geography explores many aspects of the human and physical environment. This chapter introduces the discipline of geography and explains its many branches. The scope of physical geography covered in this text is introduced. Geographers are also very interested in the relationship between humans and the earth. In this first chapter linkages are made between physical geography and some very important environmental issues facing humankind.
Another aim of this chapter is to introduce you to some of the major ideas that help to organize the study of physical geography. These are the ideas of spheres (or realms), scales, systems, and cycles. The idea of systems is especially important as it is the framework for studying Earth surface processes that is used throughout the book.
- Geography is the study of the changing patterns and processes taking place at the Earth’s surface.
- Geographers also study human activities that take place on the Earth and the relationships between human activities and the natural world.
- Geography has two approaches,: regional geography and systematic geography.
- Regional geography examines the characteristics of particular places on the Earth.
- Systematic geography looks for principles that allow us to explain and predict the patterns and processes that we observe on the Earth.
- Systematic geography can be divided into human geography and physical geography.
- Human geography examines economic, social and behavioral processes while physical geography examines natural processes.
- Physical geography includes climatology, geomorphology, coastal and marine geography, geography of soils, and biogeography.
- Hazard assessment and water resources bring together both human and physical geography by studying how humans affect and are affected by the natural world.
- Geographers use specialized tools including maps, geographical information systems (GIS), and remote sensing to allow them to portray information that varies spatially on the Earth’s surface.
- A systems approach considers the interconnections and flows of material and energy in natural systems.
- Physical geography is also concerned with the relationships between humans and their environments. Environmental change is caused by both natural and human processes. Some important topics of global change that physical geographers are studying are global climate change, the carbon cycle, biodiversity, pollution, and extreme events.
- The natural systems and processes that are studied in physical geography can be considered to operate in four great spheres (or realms): the atmosphere, the lithosphere, the hydrosphere, and the biosphere.
- The lifelayer is the focus of physical geography. It is the shallow surface layer where the four realms (or spheres) interact and where most life forms are found.
- Processes operating in the four spheres are studied at different spatial scales or levels of detail. These range from global, through continental and regional, to local and individual scales.
- The processes studied in physical geography also operate at a range of time scales; some act over millions of years while others act over seconds.
- The processes of the four realms interact in a very complex way to shape the life layer. Viewing these interactions as systems allows us to unravel and understand that complexity.
- A system is a set of things that are somehow related or organized.
- Most natural systems are flow systems in which matter or energy flow along pathways interconnected in a structure.
- All flow systems have a power source.
- Open flow systems have inputs and outputs, while closed flow systems do not.
- Cycles are closed matter flow systems. In a cycle, a fixed amount of material is continually recirculated through a series of pathways or loops.
- Feedback in a flow system occurs when the flow in one pathway affects the flow in another. Positive feedback increases flow while negative feedback reduces it.
- Negative feedback in a flow system tends to produce stability or equilibrium.
- Time cycles are periodic changes in system flow rates that occur over periods ranging from hours to millions of years.
- Studying the systems of the life layer and their interactions leads to a better understanding of the human habitat, environmentalproblems, and global change.