Jean-Baptiste Lamarck
Proposed an early theory of evolution based on the inheritance of acquired characteristics, though later superseded by Darwin's theory.
Most quoted
"It is not the organs, that is to say, the nature and form of the parts of the body of an animal, which have given rise to its habits and its particular faculties. It is, on the contrary, its habits, its manner of life, and the circumstances in which its ancestors have found themselves, which have, in the course of time, really constituted the form of its body, the number and state of its organs, and, in short, the faculties which it possesses."
— from Philosophie Zoologique, 1809
"Second Law: All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young."
— from Philosophie Zoologique, 1809
"It is not the organs, that is to say, the nature and form of the parts of the body, that have given rise to their habits and particular faculties, but it is, on the contrary, their habits, their manner of life, and the circumstances in which the individuals of which the race is formed have found themselves, that have with time constituted the form of the body, the number and state of their organs, and finally the faculties which they possess."
— from Philosophie Zoologique, 1809
All quotes by Jean-Baptiste Lamarck (412)
It is not the organs, that is to say, the nature and form of the parts of the body of an animal, which have given rise to its habits and its particular faculties. It is, on the contrary, its habits, its manner of life, and the circumstances in which its ancestors have found themselves, which have, in the course of time, really constituted the form of its body, the number and state of its organs, and, in short, the faculties which it possesses.
The production of a new organ in an animal body, being a new need that continues to make itself felt, soon gives rise to this organ, if the raw material necessary for its formation is present.
All that has been acquired, begun, or changed in the structure of individuals during their life, is preserved in the new individuals who are born from them, provided that the acquired changes are common to the two sexes, or to the individuals who produced the new forms.
Nature, in her operations, has always proceeded by degrees, and has never made leaps.
Life, in general, is a purely physical phenomenon.
The environment acts on the form and organization of animals, and this action is not direct, but indirect.
The needs of animals, and the circumstances in which they find themselves, are the true causes of the development and modification of their organs.
The progressive march of nature is not uniform in all its parts.
The more frequently and sustainedly an organ is used, the more it develops and strengthens, and the more it is neglected, the more it weakens and deteriorates.
Nature has produced all the species of animals successively, and has not created them all at once.
The will of the animal, when it is directed towards a certain object, can modify its organs.
The earth is not a dead body, but a living one.
The true order of things is that the needs determine the organs, and not the organs the needs.
The influence of circumstances is the most powerful means of modifying the organization of animals.
The progress of nature is not always direct, but often circuitous.
The classification of animals should be based on their organization, and not on their external characters.
The simplest forms of life have given rise to the most complex ones.
The changes that occur in the organization of animals are always gradual and imperceptible.
The study of nature is the most noble occupation of man.
The existence of life is a continuous process of change and adaptation.
Contemporaries of Jean-Baptiste Lamarck
Other Biologys born within 50 years of Jean-Baptiste Lamarck (1744–1829).