Inheritance of acquired characteristics--论文代写范文精选

生物学激发这种差异,自然在这里适用。DNA复制不解释产生分裂的函数。如果配子结合形成生殖细胞,它们的DNA是合成所需的蛋白质。偏差可以适应达尔文主义框架。下面的论文代写范文进行论述。

That organisms do not inherit acquired characteristics is rather obvious, but the underlying reason for it is subtle, and stems from constraints on the kind of structure that is able to self-replicate. Analysis of the formal requirements for self-replication led von Neumann (1966) to postulate that a self-replicating automaton consists of coded information that gets used in two distinct ways. The first way is as a set of self-assembly instructions that are actively deciphered to construct a replicant. In this case, the code functions as interpreted information. The second way is as a self-description that is passively copied to the next replicant. In this case, the code functions as un-interpreted information. (To put it more loosely, the interpreting can be thought of as now we make a body, and the un-interpreted use of the code as now we make something that can itself make a body.) Since biology is the field that inspired this distinction, naturally it applies here. DNA is copied—without interpretation—to produce gametes during meiosis. If gametes unite to form a germ cell, their DNA is decoded—interpreted—to synthesize the proteins necessary to assemble a body. There are of course deviations from this in present-day life, viruses being an oft-cited example, but these deviations can be accommodated within a Darwinian framework.

  The most salient consequence of using a self-assembly code to replicate is that inheritance of acquired characteristics is (by and large) prohibited. What gets transmitted from parent to offspring in organisms is genetic self-assembly instructions, one set from each parent, and these instruction sets have not changed since they were formed through meiosis. So learned behavior and knowledge are not inherited by offspring. Thus biological organisms are shielded from change accrued during a lifetime.

  It has been suggested that the evolutionary character of culture reflects that cultural traits such as memes or artifacts are self-replicating automata, or replicators[6] (Aunger, 2000; Lake, 1998). But even speaking loosely or metaphorically, an idea or artifact or meme cannot be said to possess a code that functions as both a passively copied self-description and a set of actively interpreted self-assembly instructions (Gabora, 2004). And accordingly, in culture acquired change is inherited. This is why the characteristics of artifacts can change considerably faster than the genomes of the individuals who produce them. Since viruses also replicate by way of a self-replication code (although not exclusively their own), they too are shielded by and large from inheritance of acquired traits. Thus epidemiological treatments of culture are similarly flawed (their infectiousness notwithstanding).

  Lake (1998) argues that some but not all socially transmitted ideas and artifacts are replicators. The argument begins with a distinction between the expression versus the symbolically coded representation of cultural information. Whereas, for example, singing a song is an expression of a musical concept, a musical score is a representation of it. As another example, the spontaneous verbal explanation of an idea is an expression, whereas the text version of it is a representation. Lake comments that some cultural entities, such as village plans, constitute both a representation of a symbolic plan, and an expression of that plan, because they are both expressed by and transmitted through the same material form. However neither the expression nor the representation of a plan involves either interpreting or uninterpreted copying of a self-assembly code. A village plan does not, on its own, produce little copies of itself. A musical score does not generate offspring scores. The perpetuation of structure and the presence of a symbolic code do not guarantee the presence of a replicator. Symbolic coding is not enough; it must be a coded representation of the self.

  This distinction was recognized by Maturana and Varela (1980), who use the term allopoietic to describe an entity (such as a village plan) that generates another entity (such as a village) with an organization that is different from its own (e.g. while a village plan is a two-dimensional piece of paper, it generates something that is three dimensional and constructed of a variety of materials). Maturana and Varela contrast this with autopoietic, a term used to describe an entity composed of parts that regenerate themselves and thereby reconstitute the whole. It thus generates another entity with an organization that is nearly identical to its own. A self-replicating automaton is autopoietic. Socially transmitted elements of culture are not.

 Treating Units of Cultural Information as Separately Evolving Lineages
  The Darwinian view of culture has led to models that treat each unit of cultural information as a separately evolving lineage (Boyd & Richerson, 1985; Cavalli-Sforza & Feldman, 1981; Durham, 1991). These models examine the conditions under which such mutated cultural units pass vertically through a family, or horizontally through a community by imitation within an age cohort, and proliferate. To justify that this kind of Darwinian approach is viable even when there is nothing actually replicating, it was shown that a mathematical model of culture can exhibit replicator dynamics without any underlying self-replicating structure (Henrich & Boyd, 2002). On the basis of this it is claimed that cultural evolution proceeds without self-replication of any kind. The question, however, is not whether their model exhibits replicator dynamics (a concept that does not capture the complex, adaptive, open-ended nature of even biological evolutionary change). The question is does it exhibit cultural dynamics? Is it coming up with things like hopscotch and wedding vows?

  Kauffman (1999) argues that this kind of approach is impoverished, in part because it suffers from the inability to account for the source of new cultural forms. As he puts it A rich web of conceptual interactions is at work as humans happen upon, design, and implement a combinatorially exploding diversity of new goods and services. This web structure of technological and cultural evolution is far richer, and far closer to the truth, than mere meme descent with modification.  

  It has been shown that the mind possesses the kind of small-world structure that characterizes many complex systems (Schilling, 2005). The description of culture and the minds that constitute it as web-lik echoes current descriptions of the earliest forms of life, and he and others have provided an impressive body of theoretical and empirical evidence that this kind of self-organized, web-like structure is essential to the capacity to evolve (Kauffman, 1993). In a similar vein, Maturana and Varela (1980) argue that autopoietic organization is the defining characteristic of life—and indeed what makes a structure evolvable. What autopoietic organization offers is the potential for a self-sustained stream of interacting and combining, resulting in new forms with new dynamics. 

  The autopoietic organization of the human mind arises from the associative structure of memory. The fruits of associative processes (e.g. analogy, concept combination, divergent thinking) serve as ingredients for analytic processes (e.g. logic, symbol manipulation, formal operations), and vice versa (Gabora, 2000, 2002, 2003). The upshot is an ability to internalize the world (in terms of both its causal and its correlational structure), and an unprecedented capacity for creativity.

  Treating one kind of cultural information in isolation from others is akin to removing organs from a dissected animal one by one and hoping to understand each in isolation from the others and the organism at large. It is reductionist. Ideas may take seemingly static forms in the physical world such as works of art or books of government policy. But in the minds of those who behold them they are charged with the potential to dynamically interact with goals, plans, schemas, desires, attitudes, fantasies, and unborn ideas, and it is through these interactions that their meaning and significance are derived. Very often this happens in a social milieu, each individual providing the idea with a different context, a different ecology of mind in which to be understood, and therefore able to flesh it out or give it a fresh twist. 

  In this way, different domains of human culture influence, cross-fertilize, or contaminate one another to such an extent that it is misleading to consider them separate lineages. In short, the genre of model that treats cultural information as constituting separate lineages evolving through Darwinian processes, and that does not take the self-replication issue seriously, fails to incorporate the small-world, autopoietic structure of the mind, which is essential to its capacity to perpetually see one thing in terms of another and thereby adapt, invent, and revise. These models may exhibit cumulative change of transmitted traits in the same sense that a each time a tape is copied it accumulates more distortion. But they are not able to generate novelty in a manner that is anything like human creativity, and therefore can have little bearing on the observed richness of human culture.

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