(Darwinian). Darwin's theory is that different forms of animal and vegetable life are due to small variations, and that natural selection is a main agent in bringing them about. If favourable, these variations are perpetuated, if not they die off.
Spencer's theory is that the present multitude of objects have all sprung from separate atoms originally homogeneous.
“Evolution is the integration of matter and concomitant dissipation of motion, during which the matter passes from an indefinite, incoherent homogeneity to a definite coherent heterogeneity; and during which the retained motion undergoes a parallel transformation.” —Spencer: First Principles, part ii. chap. xvii. p. 396.
its process, according to biologists.
Assuming the existence of some element, call it protyle (2 syl.), in time we get matter, and motion. From matter and motion proceed cohesion and repulsion, and from cohesion and repulsion we get crystals. Next comes chemical action into play, from which springs primordial protoplasm, or the protoplasmic clot of purely chemical origin.
By further development the chlorophyll cell is formed, with its power to assimilate, and this will account for air, water, and minerals.
By parasitism next comes the proto-bacillus or fungus, living on the green cells. And then will follow the protozoön, the first example of animal life.
Part ii. (1) The Amæba is the lowest of known animals, a mollusc, with the sole power of locomotion. (2) The Syn-amæba is multicellular, with an organism adapted for sensation, digestion, and the power of reproduction.
(3) Then will come the Gastrula, an organised being, with an external mouth.
(4) Next the Hydra or Polyp, which has localised sense-organs and instincts.
(5) Then the Medusa, with nerves, muscles, and nerve functions.
(6) Next come worms, which have special sense organs; and
(7) Then the Himatega, or Sack-worm, which has a rudimentary spinal cord.
Part iii. From the Sack-worm to Man. (1) The larvæ of Ascidians.
(2) Lowly-organised fish, like the Lancelet. (3) The Lepidosiren, and other fish.
(4) The Amphibians.
(5) Birds and Reptiles.
(6) Monotremata, which connect reptiles with mammals. (7) Morsupials.
(8) Placental Mammals,
(9) The Lemuridæ.
(10) The Simiadæ.
(11) The Monkey tribe, consisting of the New
World monkey (called Platyrhines), and the Old World monkeys (called Catarhines, 3 syl.). (12) The Missing Link between the catarhine monkey and man. The Alali is thought by some to supply this link. It is one of the monkey tribe which approaches nearer to the human species than any other yet discovered.
This is no place to criticise the theory of evolution, but merely to state it as briefly and plainly as possible.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Evolution from Fact Monster: