Evolution | Page 4

animal life a development theory was first clearly set
forth by Karl Ernst von Baer (died 1876). In his
"Entwickelungsgeschichte der Tiere" (1828), the author explains
"Entwickelung" as a progress from simple to complex forms. He

believes that in evolution there is a fundamental idea that "goes through
all the forms of cosmic and animal development." A predecessor of von
Baer had been the Frenchman, Lamarck. From von Baer, Herbert
Spencer, about 1850, adopted the definition of evolution.
The hypothesis entered a new phase through Charles Darwin's
epochmaking work: "The Origin of Species." The keynote of Darwin's
theory is Natural Selection, by which term the development of all living
forms is referred to the working of certain laws which in the
reproduction of plants and animals preserved those individuals which
were best fitted to survive the struggle for existence. The Darwinian
theory may be summarized thus:
The Darwinian Hypothesis.
1. Every kind of animal and plant tends to increase in numbers in a
geometrical progression.
2. Every kind of animal and plant transmits a general likeness, with
individual differences, to its offspring.
3. Past time has been practically infinite.
4. Every individual has to endure a very severe struggle for existence,
owing to the tendency to geometrical increase of all kinds of animals
and plants, while the total animal and vegetable population (man and
his agency excepted) remains almost stationary.
5. Thus, every variation of a kind tending to save the life of the
individual possessing it, or to enable it more surely to propagate its
kind, will in the long run be preserved and will transmit its favorable
peculiarity to some of its offspring, which peculiarity will thus become
intensified till it reaches the maximum degree of utility. On the other
hand, individuals presenting unfavorable peculiarities will be ruthlessly
destroyed (Survival of the Fittest), [tr. note: sic punctuation]
The basis of the theory then is that animals and plants multiply very
rapidly and, second, that the offspring always vary slightly from the

parents, though generally very closely resembling them. Mr. Alfred
Russel Wallace says: "From the first fact or law there follows,
necessarily, a constant struggle for existence; because while the
offspring always exceeds the parents in number, generally to an
enormous extent, yet the total number of living organisms in the world
docs not, and can not, increase year by year. Consequently every year,
on the average, as many die as are born, plants as well as animals; and
the majority die premature deaths. They kill each other in a thousand
different ways; they starve each other by some consuming the food that
others want; they are destroyed largely by the powers of Nature--by
cold and heat, by rain and storm, by flood and fire. There is thus a
perpetual struggle among them which shall live and which shall die;
and this struggle is tremendously severe, because so few can possibly
remain alive--one in five, one in ten, often only one in a hundred or
even in a thousand.
"Then comes the question, Why do some live rather than others? If all
the individuals of each species were exactly alike in every respect, we
could only say it is a matter of chance. But they are not alike. We find
that they vary in many different ways. Some are stronger, some swifter,
some hardier in constitution, some more cunning. An obscure color
may render concealment more easy for some, keener sight may enable
others to discover prey or escape from an enemy better than their
fellows. Among plants the smallest differences may be useful or the
reverse. The earliest and strongest shoots may escape the slug; their
greater vigor may enable them to flower and seed earlier in a wet
autumn; plants best armed with spines or hairs may escape being
devoured; those whose flowers are most conspicuous may be soonest
fertilized by insects. We can not doubt that, on the whole, any
beneficial variations will give the possessors of it a greater probability
of living through the tremendous ordeal they have to undergo. There
may be something left to chance, but on the whole the fittest will
survive." ("Darwinism"p. 7).
The same writer gives a probable instance of the working of Natural
Selection in the origin of certain aquatic birds called dippers. He says:
"An excellent example of how a limited group of species has been able

to maintain itself by adaptation to one of these 'vacant places' in Nature,
is afforded by the curious little birds called dippers or water-ouzels,
forming the genus Cinclus and the family Cindidae of naturalists.
These birds are something like small thrushes, with very short wings
and tail, and very dense plumage. They frequent, exclusively, mountain
torrents in the northern hemisphere, and obtain their food entirely in the
water, consisting, as it does, of