A population according to the funk and Wangnall Dictionary is a grouping of individuals subject to the processes of birth, death, and migration.. During the first 2 million years of our history the human population had very little effect upon the overall world ecosystem, with no more than 10 million members. In the New Stone Age, less than 10,000 years ago, the number of humans began to increase more rapidly. By the beginning of the Christian era it had reached 250 million, and by the year 1650 CE up to half a billion(Internet Source)Reprodu ....