LB236-240嘉芸

Lenneberg (1967)

content： Although it is quite conceivable that behavioral propensities yield more readily to selection pressures and are, perhaps, also more easily affected by genetically conditioned variations, thus changing at a more rapid rate than skeletal structure, for instance, we must still remember that all evolutionary changes affect animals as a whole. Entire patterns of life, so to speak, are altered but at each time-slice there is, necessarily, full integration and mutually adaptive interaction of all of the animal’s features; it is the condition for viability and successful continuation of the species. This consideration has an important consequence for reasonable expectations of the phylogenetic history of one specific trait, such as human language. Individual traits of an extant species can never have a continuous history because they do not evolve independently from the rest of the animal. Thus we see that there is every reason to believe that animal communication is a discontinuous affair and that logical commonalities among communication systems are not necessarily indicators of a common biological origin. FIG. 6.3. Schema of the evolution of the Hominoidea. (c) The Sharing of Traits. These assertions are not contradicted by the wealth of evidence that some sort of symbolic behavior can be demonstrated in a wide variety of animals, that the communication of affect is very common, or that territoriality, protection of the young, or maternal behavior is frequently accompanied by vocalizations. It is true that animals share certain traits; it follows directly from the tree-like relationship between species. Notice, however, that the phylogenetic relationship between species cannot, in most cases, be represented by a single, unique tree-diagram that accounts for absolutely all of the commonalities and all of the specific differences. A tree that characterizes the relationship of skeletal structures of certain species fairly well, may differ in some (usually small) respect from a tree that characterizes the relationship between given protein structures (Goodman, 1963).

FIG. 6.4. Tree diagrams or descent may be represented as Euler-Venn diagrams.

(a) is a representation of Fig. 6.3 (Chapter Six). Individual traits of behavior are often distributed over species in such a complex way that tree diagrams cannot be used at all, and set diagrams can only be used at the risk of oversimplification.

(b) is a hypothetical representation of vertebrate communication systems that could not be shown by a single tree.

This is due to a number of circumstances; for example, certain aspects of life do not allow of as many (or any) variations as others; or there may be only one or very few possible biochemical solutions to a given problem posed by the environment so that a similar condition comes about more than once throughout the animal kingdom; or certain features are lost or added by individual species.

Tree-diagrams may be converted to Euler-Venn diagrams such as shown in Fig. 6.4 where (a) is a representation of the tree in Fig. 6.3 and (b) is a hypothetical diagram that might show some of the relationships of individual traits, some of them pertinent to human language. Each of the rings may be labelled; the labels tend to become more abstract as we move from center to periphery. The inner circles represent phenomena that can be directly observed on present-day animals. Each encompassing ring is a postulation lf a more general form of the contemporary phenomenon. If an outer ring be vocalizations, this will not be a homogeneous set of behaviors but a collection of types of behavior each of which is today a highly specialized biological function. Thus we see once more that the sharing of traits does not necessarily reveal the history or nature of any specific development.

Ⅱ. ARE BIOLOGICAL THEORIES OF LANGUAGE DEVELOPMENT COMPATIBLE WITH CONCEPTS OF GENETICS?

Before we proceed with further speculations about the biological origins of language, we must pause to ask whether present-day concepts of genetics and development are compatible with the facts known about language.

(1) Genes and Ontogenetic Development

The first problem is posed by what is known about the specific action of genes. DNA molecules, the biochemical correlates of genes. Probably do no more than control the protein synthesis within the cell. The undifferentiated cells of higher animals have, however, a very large repertoire of different “instructions” for different types of synthesis, and these come into play at various stages of development (Beermann, 1963). The puzzle now is: if the inherited genetic information concerns essentially nothing but intracellular events, how could something like the capacity for language have a genetic foundation? The phenomenon is, after all, entirely supracellular or even more general, namely an interrelation of activities of complex assemblies of cells.

This puzzle is, of course, not peculiar to the problems of the genetic basis of language but to the relationship between genic action and the inheritance of traits in general. Although we can only speculate on this point, our speculations with regard to language are no more daring than with regard to most other structural or functional features.

Animals develop as an integrated whole including structure, function and behavioral capacities; the latter two are not secondary installations after embryogenesis. Therefore, it may not be too far-fetched if we say a word about development in general, the assumed role of genes in ontogenetic and phylogenetic development, and how these concepts apply to the development of language.

It is common knowledge that the first cells formed during mammalian ontogenesis have embryological equipotentiality. Up to the stage called gastrulation, the cell aggregate may be divided artificially in two, and each remaining half will develop into a well-shaped individual. But soon some of the cells in the gastrula become specialized, a division of labor has set in among the cells which soon deprives them of the capacity to change their own structure and function back to the original state. A certain spot in the gastrula begins to act on surrounding cells, thus inducing fast cell division, local expansion, folding, invagination, tubular structures, inclusions, etc. We speak of an organizer that has developed and which has caused some differentiation in its neighborhood. Organizer after organizer develops. At later stages entire tissues or organs serve as organizers or inducers for other tissues and organs.

supplement information：分子生物學與遺傳學：

遺傳學在孟德爾定律以DNA雙螺旋鏈解說染色體的形成與運作規則後，利用分子生物學的研究方法與工具，使傳統遺傳學的問題有了重大進展。現代分子遺傳學對遺傳信息傳遞由DNA到RNA到蛋白質的中心法則的發現，揭示了遺傳、發育和演化的內在聯繫。真核基因體的結構及其表達調控機制得到機械性細節的闡明。多細胞高等生物體中分化細胞的細胞核內仍含有全套遺傳訊息，各組織之細胞分化只是部分基因選擇表達的結果。故，遺傳控制發育的過程可以分子生物學的慨念歸結為：基因如何按照一定的時間與空間次序選擇地表達，從而控制特定蛋白質的生成與分佈，達成細胞的分化與個體發育。對發育來說，最重要的不是個別基因的表達過程而是這些過程彼此之間在時空上精密的聯繫與配合，此亦即是發育的遺傳程序。此種遺傳程序是演化過程中，編碼在基因體DNA序列上並在配子(卵子與精子)發生過程中儲存於配子的結構中。將來的探討問題將是演化形成中遺傳程序是以何種方式編碼在基因體中，這種編碼在DNA的一次元序列如何控制生物體的三次元形態發育。

來源 : http://cell.lifescience.ntu.edu.tw/old_version/academic/

brief summary：演化發展的改變會影響動物的全部，也是物種的生存條件，更能成功地物種延續。說話為動物互相適應交流互動的特徵。現存的物種的個體特徵絕不會有持續性發展的歷史，因為無法從剩餘的動物獨立演化出來，然而我們相信動物溝通是非持續性的事情，在溝通系統中有邏輯的共用不一定是共同生物起源的指標。有豐富的證據不會牴觸特徵的共用分享:在廣泛的動物物種中，象徵性行為可被顯示出來，如:互相溝通、占有地盤、保護幼小、母性行為，皆很常伴隨著聲音的發出。動物共用某種特徵是可能的。與基因有關的個體發育及動植物種類史發展和語言發展有相關性。

How my tool helped me to solve problems? 我使用的工具是網路上的字典搜尋引擎，用來查詢我不懂的單字，例如phylogenetic和gastrulation是比較學術的專有名詞，透過此工具查詢讓我能繼續閱讀下去。