Quotes About Evolution

I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient.

unusual degree. This family became divided eight generations

In a series of forms graduating insensibly from some apelike creature to man as he now exists, it would be impossible to fix on any definite point where the term 'man' ought to be used.

Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life...

Why is The Origin of Species such a great book? First of all, because it convincingly demonstrates the fact of evolution: it provides a vast and well-chosen body of evidence showing that existing animals and plants cannot have been separately created in their present forms, but must have evolved from earlier forms by slow transformation.

We here see in two distant countries a similar relation between plants and insects of the same families, though the species of both are different. When man is the agent in introducing into a country a new species this relation is often broken:

It was evident that such facts as these, as well as many others, could only be explained on the supposition that species gradually become modified; and the subject haunted me.

Pueden los instintos adquirirse y modificarse por medio de la selección natural? ¿Qué diremos del instinto que lleva a la abeja a hacer celdas, y que prácticamente se ha adelantado a los descubrimientos de notables matemáticos?

Dos animales caninos, en tiempo de hambre, luchan mutuamente por conseguir el alimento que necesitan; pero la planta que nace en los linderos del desierto lucha por la existencia contra la sequía, aunque con más propiedad se diría que depende de la humedad.

El embrión no queda afectado, y sirve como indicio de la pasada condición de las especies. Por eso sucede que las especies existentes, durante los primeros períodos de su desarrollo, se parecen a menudo a formas antiguas y extinguidas

La belleza, en muchos casos, parece ser debida por completo a la simetría del crecimiento. Las flores se clasifican entre las producciones más hermosas de la naturaleza; pero se han hecho visibles por contraste con las hojas verdes, y por consiguiente hermosas, al mismo tiempo para que puedan ser fácilmente observadas por los insectos.

We shall best understand the probable course of natural selection by taking the case of a country undergoing some slight physical change, for instance, of climate. The proportional numbers of its inhabitants will almost immediately undergo a change, and some species will probably become extinct.

it is so important to bear in mind the probability of conversion from one function to another

modern geology has almost banished such views as the excavation of a great valley by a single diluvial wave, so will natural selection, if it be a true principle, banish the belief of the continued creation of new organic beings, or of any great and sudden modification in their structure.

What natural selection cannot do, is to modify the structure of one species, without giving it any advantage, for the good of another species; and though statements to this effect may be found in works of natural history, I cannot find one case which will bear investigation.

las variaciones y diferencias individuales favorables, y la destrucción de aquellas que son nocivas, es lo que hemos llamado selección natural o supervivencia de los más aptos.

Until recently the great majority of naturalists believed that species were immutable productions, and had been separately created. This view has been ably maintained by many authors. Some few naturalists, on the other hand have believed that species undergo modification and that the existing forms of life are the the descendants by true generation of pre-existing forms.

But that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species.

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us.

we are always slow in admitting great changes of which we do not see the steps.

Puede decirse metafóricamente que la selección natural está haciendo diariamente, y hasta por horas, en todo el mundo, el escrutinio de las variaciones más pequeñas; desechando las que son malas, conservando y acumulando las que son buenas, trabajando insensible y silenciosamente donde y cuando se presenta una oportunidad, en el mejoramiento de todo ser orgánico en relación con sus condiciones orgánicas e inorgánicas de vida.

pero la selección natural no puede modificar la estructura de una especie, sin darle ninguna ventaja, para provecho de otra especie;

The differences of Mr. [Patrick] Matthew's views from mine are not of much importance: he seems to consider that the world was nearly depopulated at successive periods, and then re-stocked;

On peut démontrer ainsi ni la stérilité ni la fécondité ne fournissent aucune distinction certaines entre les espèces et les variétés.