In several recent publications I have developed, from different points of view, some considerations which tend to bring out a certain influence at work in organic evolution which I venture to call "a new factor". I give below the list of references  to these publications and shall refer to them by number as this paper proceeds. The object of the present paper is to gather into one sketch an outline of the view of the process of development which these different publications have hinged upon.
The problems involved in a theory of organic development may be gathered up under three great heads: Ontogeny, Phylogeny, Heredity. The general consideration, the " factor " which I propose to bring out, is operative in the first instance, in the field of Ontogeny; I shall consequently speak first of the problem of Ontogeny, then of that of Phylogeny, in so far as the topic dealt with makes it necessary, then of that of Heredity, under the same limitation, and finally, give some definitions and conclusions.
In evolutionary biology, the Baldwin effect describes the effect of learned behavior on evolution. In brief, James Mark Baldwin and others suggested during the eclipse of Darwinism in the late 19th century that an organism's ability to learn new behaviors (e.g. to acclimatise to a new stressor) will affect its reproductive success and will therefore have an effect on the genetic makeup of its species through natural selection. Though this process appears similar to Lamarckian evolution, Lamarck proposed that living things inherited their parents' acquired characteristics. The Baldwin effect has been independently proposed several times, and today it is generally recognized as part of the modern synthesis.
The 'Baldwin effect' has now been demonstrated at the genetic level in a population of dark-colored lizards adapted to live on a lava flow in the desert.
Highlights, Quotes, Annotations, & Marginalia
One explanation has been that many of an animal’s traits are not fixed, but can change during its lifetime. This “phenotypic plasticity” enables individual animals to alter their appearance or behavior enough to survive in a new environment. Eventually, new adaptations promoting survival arise in the population through genetic changes and natural selection, which acts on the population over generations. This is known as the “Baldwin effect” after the psychologist James Mark Baldwin, who presented the idea in a landmark paper published in 1896. ❧
September 11, 2018 at 08:57AM
Journal article available at: https://www.cell.com/current-biology/pdfExtended/S0960-9822(18)30899-6
While most side-blotched lizards living in the Mojave desert match the colour of its sand, those