In the modern age, it can often be difficult to conceive of a time without machinery or technology.
However, early humans had only the tools that they could make for themselves out of the materials they had at hand.
The concept of evolution became generally accepted among people of science, following publication of the book, and in the next few years the entire science of biology underwent a rapid remoulding on the basic theme of organic evolution.
Charles Darwin wrote also a small book, "Descent of Man", which was published 12 years after the appearance of "Origin of Species".
the period of reptiles, which ended about 70 million years ago, and the duration of which is estimated to have been nearly 140 million years), or that of mammals in the early part of the Caenozoic Era (i.e.
the current geological era, which started about 70 million years ago).The present century has witnessed a rapid progress in our understanding the mechanism of inheritance among organisms.Thus the branch of Biology, called Genetics, has developed fast. A printed version may become availbale in the future. When this happens in populations of the same species, living in different areas with somewhat different conditions, this may lead to the populations becoming, in due course, different and new species. This publication may be reproduced for limited educational or academic use, however please enquire with the author. Verma is Retired Professor of Zoology and Principal, Government P. According to this theory living forms are not static; they change with the passage of time in order to become better adapted to the existing conditions.For those early humans who lived near the sea, rivers or lakes, fish and other seafood were often a part of their diet.Some of these fish were caught using spears, but most early humans used fishing hooks on lines or nets. Early humans often used cast nets with stones attached to the edges to keep the fish from escaping.In this book the author described that, like other organisms, Man had been a product of evolution, and that he had descended from some primitive tree living apes, his closest living relative being the chimpanzee.Similar views had been presented by a strong supporter of Charless Darwin, Thomas Huxley in 1863 in his book, "Evidences as to Man's Place in Nature".While wooden arrows with simple sharpened points did often have the penetrating power of arrows tipped with points, the broad edge of the flint arrow tip caused more tissue damage, which resulted in the prey bleeding out and dropping more quickly.For many years archaeologists thought that the sole point of flint knapping was to produce sharp arrow points for arrows or spears.