Locusts are cool. They can come in two phases ... solitary and migratory. These two phases look and act very much like different species. They are genetically identical (as in no significant differences).
The solitary phase locusts sit around with fat bodies and stubby wings, munching on juicy goodies. The migratory phase locusts (not genetically different) have lean bodies, and large wings. They cruise over great distances.
What has happened? The story, in part (its ALWAYS "in part") is that nutritional "experiences" set development down one of the two paths, solitary versus migratory. Good food -> solitary. Lousy food -> migratory. Clever.
How does this happen? Different sets of genes get turned on and turned off in specific combinations as a function of nutritional state (and potentially other experiences). This leads to different outcomes.
So, genes are absolutely essential, but not all potential genetic "information" is used. Which genes are used, and the combinations they are used in, depends upon experience. Experience in this way can be thought of as selecting among potential pathways rather than as adding information. [That distinction between selection and instruction in development is moot; it's made for emphasis.]
So, while marveling about this I look into the mirror. I see eyes and a nose reflected back at me. They look as different from each other as do the two locusts. Here its not a matter of being one species, but one individual. My genetics friends tell me that my eyes and nose have (for all practical purposes) the same genes. What is happening?
Precursor cells for eyes and noses live in different parts of the embryo. As a result they have different experiences. They get activated in different combinations. Voila!
Genes are essential (or no locusts, no eyes, no noses). Genes need environments (or no locusts, no eyes, no noses). Which is "more" important, genes or environment? As Donald Hebb asked, which is more important for a rectangle, the length or the width. Proportions can vary, but each dimension is essential (or no rectangles, on single straight lines).
Brain circuits that contribute to behavior are formed by similar rules. These circuits come in many different shapes, each of which contains a richness of internal connections, chemical mediators, etc. We can look at the anatomy, but need to understand the functions.
Let's pretend that some brain circuits, and some locusts, eyes and ears remind us of rectangles. Rectangles and other geometric figures in turn remind us of one fundamental property found in all patterns. Patterns contain parts and also rules of connection among the parts. Without the parts, no pattern. Without the connections, no pattern. Notes in a melody are in this way also patterned, as are words in a newspaper article, the tiles on a bathroom floor, etc. Capturing pattern, in both its parts and multiple relations, is a major intellectual as well as aesthetic challenge.
Behavior is patterned. Here the patterning involves, in a central way, the idea of time. It also involves layers of organization that somehow work together. Music is a better analogy than rectangles. Notes, melody lines, chords, rhythms, and a host of other features make music what it is. The analogy between music and behavior can be informative. In each case we have flow patterns, not static patterns.
We often use rectangle type logic to talk about behavior, but that is an error. A given act is not really a thing, but a flow pattern. We throw nouns at process for convenience, and in doing so run the danger of distorting the very "stuff" of which we wish to speak. We often pretend that behavior can be represented by a static picture, rather than as a flow pattern. Wrong. Fundamentally wrong. Behavior is a movie, not a snaphot.
That is why the interest in dynamic pattern deserves applause. Dynamic pattern applies not only to music and to behavior, but to evolution and development (ETC!). Biology is full of dynamic patterns. What we call "things" are RELATIVELY frozen (stable) representations of flow patterns. Life does not go on forever. Change is the key, even though some of this change can be relatively slow, thus providing a sense of stability. Change in turn is defined by relations. Change cannot occur in a vacuum. One must say that X changes IN RELATION TO Y, or Z. Y and Z can be more or less concrete, or more or less abstract. That is a matter of the problem addressed and the style of analysis prefered. But changing relations are where its at.
So, to wrap up, pattern in behavior is based upon relations (as are ALL patterns) and time. We need to deal explicitly with the dynamic relations that make behavior, and its development, and its evolution, possible. Relations imply that single items are insufficient. Genes, by themselves are insufficient. Experiences, by themselves are insufficient. Its the relations of genes to experiences that write the tunes.
This is one reason why developmental analyses are such an essential complement to evolutionary analyses. Evolution cannot work except through ontogeny. Development rests upon the foundations of phylogeny. Behavior rests on both. Nature and nuture become partners in the adaptive dance. So here we are. It works!
Unfortunately, we do not know how it works.
But we are learning.