One of the mysteries of geologic history is the simultaneous appearance upon the earth of specialized forms of animal life and the particular plants upon which they feed. Thus the first grazing mammals appeared in the Eocene period at the same time as the grasses upon which they feed. Similarly the bees appeared with the flowering plants, neither being able to exist without the other; for without insects to distribute pollen the seeds of many plants would be infertile, and without honey and pollen the bees would starve.
One of the most interesting examples of mutual dependence between plant and insect is that of the Yucca of the Southwest and the Pronuba moth.
The Yucca, which belongs to the Lily family, differs from most plants in having the stamens widely separated from the pistil, and in the pollen being held within a sticky fluid which prevents the wind from blowing it from plant to plant and so fertilizing the flowers. The Pronuba moth moreover is interested only in laying its eggs where the young grubs will have suitable food, for unlike many insects it feels no attraction for honey as food.
The transaction then is one which provides for the continuation of the Yucca through the fertilizing of its embryo seeds in exchange for a number of tender seeds for the young Pronuba grubs to feed upon. Neither insect nor plant could survive without the other.
The female moth visits several Yucca plants, collecting a small ball of the sticky pollen; then she flies to a mature flower, inserts her long slender ovipositor through the succulent wall of the pistil and deposits a single egg in an embryo seed. After laying each egg, the mother moth climbs the pistil and rubs some of the pollen on to the stigma and then returns to deposit another egg.
It is not only in the lower kingdoms that this cooperation and interdependence exists, for all the kingdoms of nature are closely linked together in a totality of life. In its history the earth has passed through many great changes, producing what is often referred to as the Age of Fishes, the Age of the Coal Forests, the Age of Reptiles, the Age of Mammals, etc. In these periods the clothing of all forms of life may be said to be made over to harmonize with the new style.
As H. P. Blavatsky says in The Secret Doctrine (Vol. II, page 262):
"Species and genera of the flora, fauna, and the highest animal, its crown — man, change and vary according to the environments and climatic variations, not only with every Round, but every Root-Race likewise, as well as after every geological cataclysm that puts an end to, or produces a turning point in the latter."
Along the same line G. de Purucker in a private letter explains further, — "The main point to remember is that the different great stocks of mineral, vegetable and animal and human lives follow each other with coincident or coordinate great changes of land and sea, and therefore also of climates.
"In other words, the stocks of beings, or monads, co-operate or co-ordinate and thus produce the different and serial and successive patterns of what we today call geological eras, or which the biologist and zoologist and botanist would call the successive waves of plant and animal life."
There are styles, fashions through which the world passes during which both plant and animal life is stamped with the characteristic of the times, and this characteristic is that of the race of man then beginning its rise. G. de Purucker has pointed out that while there are remnants of both the Third and Fourth Root-Races now on earth, all these now bear the stamp of our own Fifth Root-Race because living in Fifth Root-Race times. The same may be said of the so-called "modernized" plants and animals, for while of ancient stock they all have in some degree changed with the changing times. Those who are not able to adapt themselves to new conditions finally drop out and disappear.
In other words the entire life on this living earth evolves together, and the impact of a new and vigorous race accelerates certain characteristics and retards others in both the plant and animal kingdoms.
Even today, wherever the European peoples go, there is an immediate effect upon the native tribes of a lowered birth-rate, while the host of European weeds, rats, mice, and diseases which follow the colonists work havoc upon native life of all kinds.
The science of Ecology groups the plant, animal, human, and climatic complex as a social organism, which is more than the sum of its parts. It has a body to study as well as a cell, a society as well as an individual: this totality of life is called a Biome, and any intrusion of foreign elements changes the whole structure of the organism. Man, since he dominates any Biome by his presence in any locality profoundly affects every living unit composing it, and through the destruction of forests, through poor management of land leading to soil erosion, and in other ways may even change the rainfall and climate.
Ecology then would look upon the European impact upon another land, as the invasion of one Biome by another, for, as said above, the man is accompanied by other elements belonging to his former home: food-plants and weeds, rats and mice, birds, bacteria and disease germs peculiar to himself.
Any such invasion is far-reaching in its effects upon the whole, whose nature is to some degree altered throughout.
Many have observed that important food plants decline with the passing of the animals or people dependent upon them, the Beech which once covered the ground with delicious nuts upon which immense flocks of wild pigeons fed, now with the complete disappearance of the pigeons has almost ceased to bear fruit. Deer often decline through disease more rapidly in regions where predatory animals are removed than where they are allowed to remain.
Man and nature are linked on inner lines of affinity and repulsion, forming a web of life in which everything that is done affects the whole. It is the structure of a universal brotherhood in which man has dominion over the creatures of the earth, not that he may despoil them for his own uses, but that he may be the helper and protector of these brothers of the lower kingdoms.