Seaborg D M
Foundation for Biological Conservation and Research, 1888 Pomar Way, Walnut Creek, CA 94598-1424, USA.
J Theor Biol. 1999 May 7;198(1):1-26. doi: 10.1006/jtbi.1998.0896.
This paper argues that organisms are integrated, holistic systems whose phenotypic traits and genes interact with each other and natural selection. More than this, organisms are feedback systems. I introduce the term integration of the organism to refer to this idea that organisms are such interacting systems. Integration of the organisms is a major reason why most mutations are deleterious, and why the larger a mutation's effect, the greater the probability that a mutation will be deleterious. Yet, it is also why macromutations can occasionally be adaptive. Such adaptive mutations of large effect, an example of which is neoteny, must be coordinated with the generic system and ontogeny of the organism. Integration of the organism and the ability of both the phenotype and genotype to influence and interact with natural selection means a species can undergo sequential evolution, a term I coin in this paper to refer to a change in a trait causing a change in selection on a second trait, which leads to a change in the second trait, which in turn causes a change in selection on a third trait, changing it, and so on. Sequential evolution can sometimes result in closed feedback loops, in which a trait farther down the sequence affects a trait earlier in the sequence of traits. I call this process evolutionary feedback. Both sequential evolution and evolutionary feedback can sometimes cause punctuated evolutionary change. Evolutionary feedback can also act as a mechanism for stasis. Hence, evolutionary feedback is a mechanism for punctuated equilibrium. I propose that species to a large extent influence, even drive, their own evolution. This, of course, is not to suggest they do so willfully or consciously. It is proposed that there are three mechanisms for punctuated evolutionary change; these are described. Examples of and evidence for sequential evolution and punctuated evolution by evolutionary feedback are presented.
本文认为，生物体是整合的、整体的系统，其表型性状和基因相互作用，并与自然选择相互作用。不仅如此，生物体还是反馈系统。我引入“生物体的整合”这一术语来指代生物体是这样相互作用的系统这一观点。生物体的整合是大多数突变有害的主要原因，也是突变效应越大其有害可能性就越大的原因。然而，这也是宏观突变偶尔会具有适应性的原因。这种具有大效应的适应性突变，例如幼态持续，必须与生物体的遗传系统和个体发育相协调。生物体的整合以及表型和基因型影响自然选择并与之相互作用的能力意味着一个物种可以经历序列进化，我在本文中创造这个术语来指代一个性状的变化导致对第二个性状的选择发生变化，进而导致第二个性状发生变化，这反过来又导致对第三个性状的选择发生变化，使其改变，如此等等。序列进化有时会导致封闭的反馈回路，其中序列中靠后的一个性状会影响序列中靠前的一个性状。我将这个过程称为进化反馈。序列进化和进化反馈有时都会导致间断性的进化变化。进化反馈也可以作为一种静态稳定的机制。因此，进化反馈是间断平衡的一种机制。我提出，物种在很大程度上影响甚至驱动自身的进化。当然，这并不是说它们是有意或有意识地这样做。本文提出了三种导致间断性进化变化的机制，并对其进行了描述。还给出了序列进化和进化反馈导致间断性进化的例子及证据。
