Introduction to Physical Geography Flashcards
Physical geography before 1800
- Ancient Greeks and Romans were concerned with topographic descriptions of places and maps.
- Dark Age Europe merely relied on Greek and Roman texts and rejected anything against the teachings of the Church.
- Arab geographers were pioneering fieldwork, e.g. Al Muqaddasi.
- Chinese triangulation techniques for maps flourished.
The Renaissance (15th and 16th centuries)
- Renewed interest in geographical knowledge of the ancients due to issues of exploration, patriotism and colonisation;
– Period of major invention and discovery;
– Timekeeping, mapping and printing;
– Importance on real world experience (triumph of experience over authority was central).
The Age of Enlightenment (18th century)
– An intellectual and scientific revolution
– Reason through scientific induction
– Questioning of the religious orthodoxy
Captain James Cook (1728-79)
Most well known for ‘discovering’ Australia.
Also worked for the Crown with a brief to report on natural resources for exploitation (the marriage of science and imperialism).
Three expeditions 1768-80. The first, to the South Pacific aboard The Endeavour produced ethnographic studies of indigenous peoples, charts of the NZ coastline, thousands of plant and animal specimens (preserved in alcohol)
Alexander von Humboldt (1769-1859)
German explorer mainly in Latin America
In 1845, published Kosmos – a best seller – “the assemblage of all things in heaven and earth, the universality of created things constituting the perceptible world.”…based on ” facts registered by science.”
Distribution of plant species, concepts of ocean currents and their impact on climate
“I strive for are an understanding of nature as
a whole, proof of the working together of all the forces of nature..”
Charles Darwin (1809-1882)
English naturalist and geologist who developed the Theory of Evolution
Travelled on a five year expedition on the HMS Beagle to South America and the Pacific –taking Humboldt’s early writings with him.
In 1858, Alfred Wallace- a biogeographer – and using some of Darwin’s writings - published a paper ‘On the Tendency of Varieties to Depart Indefinitely From the Original Type’
In 1859, Darwin published the book On the Origins of Species that provided the
extended evidence and discussion for natural selection
Darwin’s impact on Physical Geography
- Idea of change through time – progressive development-Lyell’s uniformitarianism - long timescales
- Idea of organization – interrelationships between organisms and environment –ecology-regions-systems - humans inside rather than outside the natural environment
- Idea of struggle and selection – survival of fittest - environmental determination of human actions - processes of causality
- Randomness or chance character of variations in nature -the basis of his theory - essentially probabilistic-contrary to determinism
- …..all driving the search for more scientific laws like natural selection.
Ecology and biogeography Henry C. Cowles (US 1869-1939)
The ecological relations of the vegetation of the sand dunes of Lake Michigan, Botanical Gazette.
Shows ‘plant succession’ - walking inland across the increasingly vegetated dunes was in effect walking through time.
Introduced ideas of ‘predictable’ and ‘orderly’ changes in species composition
Soils Vasily Dokuchaev (Russia 1846-1903)
Soil as a natural body having its own genesis and its own history of development.
Soil type could be explained in relation not only to geological factors (parent material), but also to climatic and topographic factors, and the time available for pedogenesis (soil formation).
Created the first soil classification.
The beginning of Earth System science - global tectonics
Alfred Wegner (1915)
– proposed the fit was due to continental drifting;
– suggested a large supercontinent in the Carboniferous (Pangaea) slowly broke up;
– provoked strong debate;
– was, however, not taken seriously because there was no mechanism for movement over the rigid oceanic basin.
The evidence for sea floor spreading
Post WW II technology gives data
- New echo-sounding gave high resolution bathymetric maps
- New technology for discovering submarines - magnetometers.
- Clear symmetrical pattern stripes of magnetic polarity progressively becoming older, away from mid-ocean ridges.
- New global seismic network provided data on earthquake epicentres and direction of plate movement
The evidence for sea floor spreading
Theory & testing the theory
Theory
• US Harry Hess proposed the sea-floor spreading hypothesis in 1960
Testing the theory
• UK Vine and Matthews (1963) calculated rate of sea floor spreading (1–10 cm yr–1)
• Ocean drilling programme (ODP) showed that thickness of ocean sediment increased away from mid-ocean ridges with no sediments older than 200 million years were found, i.e. ocean floor is young compared to the continents.
Physical Geography since 1950
The Quantitative Revolution
– The 1950s was a period of global modernity
(science driving society).
– Arthur Strahler, a geomorphologist interested in rivers and landform change, argued the need for physically based real-world measurements (opposed to Davis).
– Processes (e.g. erosion rates) measured at smaller spatial and shorter timescales.
– Statistical inference of cause and effect
Physical Geography since 1950
Systems thinking
– GeologicalevidenceforContinentalDriftand
Plate Tectonic theory very influential
– Richard Chorley and Barbara Kennedy 1971.
Physical Geography: A Systems Approach
– The whole is more important than its component part. Holism v reductionism
– Emphasizes interactions between different parts of the environment - feedback
– New field of Complex Systems Science
– James Lovelock’s Gaia theory in 1970s
