Plants.Plants 1 x 50 in 1st year = 5050 x 50 " 2nd " = 2,5002,500 x 50 " 3rd " =125,000125,000 x 50 " 4th " = 6,250,0006,250,000 x 50 " 5th " =312,500,000312,500,000 x 50 " 6th " = 15,625,000,00015,625,000,000 x 50 " 7th " =781,250,000,000781,250,000,000 x 50 " 8th " = 39,062,500,000,00039,062,500,000,000 x 50& " 9th " = 1,953,125,000,000,00051,000,000 sq.miles--the dry surface of the earth x 27,878,400--the number of sq.ft.in 1 sq.mile = sq.ft.1,421,798,400,000,000 being 531,326,600,000,000 square feet less than would be required at the end of the ninth year.
You will see from this that, at the end of the first year the single plant will have produced fifty more of its kind; by the end of the second year these will have increased to 2,500; and so on, in succeeding years, you get beyond even trillions; and I am not at all sure that I could tell you what the proper arithmetical denomination of the total number really is; but, at any rate, you will understand the meaning of all those noughts.Then you see that, at the bottom, I have taken the 51,000,000 of square miles, constituting the surface of the dry land; and as the number of square feet are placed under and subtracted from the number of seeds that would be produced in the ninth year, you can see at once that there would be an immense number more of plants than there would be square feet of ground for their accommodation.This is certainly quite enough to prove my point; that between the eighth and ninth year after being planted the single plant would have stocked the whole available surface of the earth.
This is a thing which is hardly conceivable--it seems hardly imaginable--yet it is so.It is indeed simply the law of Malthus exemplified.Mr.Malthus was a clergyman, who worked out this subject most minutely and truthfully some years ago; he showed quite clearly,--and although he was much abused for his conclusions at the time, they have never yet been disproved and never will be--he showed that in consequence of the increase in the number of organic beings in a geometrical ratio, while the means of existence cannot be made to increase in the same ratio, that there must come a time when the number of organic beings will be in excess of the power of production of nutriment, and that thus some check must arise to the further increase of those organic beings.At the end of the ninth year we have seen that each plant would not be able to get its full square foot of ground, and at the end of another year it would have to share that space with fifty others the produce of the seeds which it would give off.
What, then, takes place? Every plant grows up, flourishes, occupies its square foot of ground, and gives off its fifty seeds; but notice this, that out of this number only one can come to anything; there is thus, as it were, forty-nine chances to one against its growing up; it depends upon the most fortuitous circumstances whether any one of these fifty seeds shall grow up and flourish, or whether it shall die and perish.This is what Mr.Darwin has drawn attention to, and called the "STRUGGLE FOR EXISTENCE"; and I have taken this simple case of a plant because some people imagine that the phrase seems to imply a sort of fight.
I have taken this plant and shown you that this is the result of the ratio of the increase, the necessary result of the arrival of a time coming for every species when exactly as many members must be destroyed as are born; that is the inevitable ultimate result of the rate of production.Now, what is the result of all this? I have said that there are forty-nine struggling against every one; and it amounts to this, that the smallest possible start given to any one seed may give it an advantage which will enable it to get ahead of all the others;anything that will enable any one of these seeds to germinate six hours before any of the others will, other things being alike, enable it to choke them out altogether.I have shown you that there is no particular in which plants will not vary from each other; it is quite possible that one of our imaginary plants may vary in such a character as the thickness of the integument of its seeds; it might happen that one of the plants might produce seeds having a thinner integument, and that would enable the seeds of that plant to germinate a little quicker than those of any of the others, and those seeds would most inevitably extinguish the forty-nine times as many that were struggling with them.
