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Palaeography is an essential skill for many historians, semioticians and philologists, as it addresses a suite of interrelated lines of inquiry.First, since the style of an alphabet, grapheme or sign system set within a register in each given dialect and language has evolved constantly, it is necessary to know how to decipher its individual substantive, occurrence make-up and constituency.
The categorisation of the past into discrete, quantified named blocks of time is called periodization. [1] This is a list of such named time periods as defined in various fields of study. These can be divided broadly into prehistorical periods and historical periods (when written records began to be kept).
The three-age system has been used in many areas, referring to the prehistorical and historical periods identified by tool manufacture and use, of Stone Age, Bronze Age and Iron Age. [1] [2] Since these ages are distinguished by the development of technology, it is natural that the dates to which these refer vary in different parts of the world.
Historical geology or palaeogeology is a discipline that uses the principles and methods of geology to reconstruct the geological history of Earth. [1] Historical geology examines the vastness of geologic time, measured in billions of years, and investigates changes in the Earth , gradual and sudden, over this deep time .
Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of ...
This timeline of prehistory covers the time from the appearance of Homo sapiens approximately 315,000 years ago in Africa to the invention of writing, over 5,000 years ago, with the earliest records going back to 3,200 BC. Prehistory covers the time from the Paleolithic (Old Stone Age) to the beginning of ancient history.
The evolutionary history of species has been described as a "tree" with many branches arising from a single trunk. While Haeckel's tree is outdated, it illustrates clearly the principles that more complex and accurate modern reconstructions can obscure.
The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the ...