In this attractively illustrated volume, eminent biologist Sir Richard Southwood offers a remarkable survey of life in all its forms, ranging from the earliest single-celled bacteria, to the evolution and extinction of animals such as the dinosaurs, to the variety of life today.
The book follows the major geological periods--such as the Cambrian, Ordovician, Silurian, and Devonian--explaining how great planetary changes such as the movement of the continents, the rising and falling of sea level, and the periods of glaciation, affected the forms of life on Earth. Beginning with the...

the virtual impossibility of extracting the many different species from a habitat with equal efficiency by a single method (e.g. Nef, 1960). 1.1 Population estimates Population estimates can be classified into a number of different types; the most convenient classification is that adopted by Morris (1955), although he used the terms somewhat differently in a later paper (1960). 1.1.1 Absolute and related estimates The animal numbers may be expressed as a density per unit area of the ground of the habitat. Such estimates are given by nearest neighbour and related techniques (Chapter 2),...