Course Summary

The Evolution of life on Planet Earth

Unit 1 - The Formation Of Planet Earth

Planet Earth formed from a mass of interstellar gas and dust. The age of Earth’s oldest rocks is discussed with information on dating procedures used. The state of Earth in the Archean period (4,600 to 2,500 million years ago) is described.

Unit 2 - Life Begins

We move back 1,000 million years to when the first life forms appeared. The surface of the land and the climate during the Proterozoic period (2,500 to 570 million years ago) are described and also the earliest life forms. The origin of life on Earth and the characteristics of living things are discussed. The theory of plate tectonics is described.

Unit 3 - Life In The Cambrian Period

The geography of the planet, living conditions at that time and the profusion of life during the Cambrian period (570 to 505 million years ago) are described. Problems of finding fossils of many of the earlier life forms are discussed.

Unit 4 - Life In The Early Palaeozoic Era

Continental movements during each of the periods - Ordovician, Silurian, Devonian - of the early Palaeozoic (570 to 360 million years ago) are described and the environment and life of each period are then discussed. During these periods life evolved from invertebrates, with the appearance of the first fish and amphibians and occupation of the land by the first land plants.

Unit 5 - Life In The Late Paleozoic Era

The two later Paleozoic periods, the Carboniferous and Permian, were periods of land colonization resulting in extensive forests of primitive trees which provided food for land animals, mainly amphibians and the first reptiles.

Unit 6 - Life In The Mesozoic Era

The Mesozoic Era (250 to 66.4 million years ago) was a period of evolution of many well-known animal species including fishes, sharks, lizards, turtles, crocodiles, and dinosaurs. The first mammals appeared, including the first placentals and the first marsupials. Another massive extinction wiped out many life forms towards the end of the era. Possible causes of mass extinctions are discussed.

Unit 7 - Life In The Tertiary Period

The Tertiary Period (66.4 to 2 million years ago) saw many changes in the configuration of the continents and big changes in sea levels and climate. Dinosaurs had been wiped out but mammals now thrived and many new species evolved, including the first primates and the ancestors of modern man. The theory of evolution is presented and discussed.

Unit 8 - Life In The Quarternary Period

This period (2 million years ago till now) covers the Pleistocene and Holocene periods and is the time when Homo sapiens migrated to all continents with drastic consequences for many of the species they encountered. The geography of the period is described and the effects of glaciation and changes in sea levels on life are discussed. The evolution of mammals and the stages of development of Homo sapiens from the Stone Age through the Iron Age and the development of city states then empires are described.

Unit 9 - The Evolution Of Homo Sapiens

This unit concentrates on the evidence now available on the evolution of Homo sapiens. Evidence presented previously on the evolution of life is reviewed. The role of DNA in reproduction and evolution is described. What is known about the evolution of Homo sapiens is presented. The future of mankind on Planet Earth, in terms of possible further evolutionary changes and the possible effects of global warming and a mass extinction, are discussed.