LBT240-243承樺

LBT240-243承樺

撰寫人：9580022 吳承樺

The pages：240 ~ 243

The multiple unfolding that takes place is entirely dependent upon temporo-spatial overlapping, a continuous meeting in time and space, a sequence of events that must be precisely synchronized so that one phenomenon may act on another at the right time at the right place. The entire ontogenetic process must be seen as a precision schedule that determines the evolvement of a temporo-spatial pattern of interactions between cells and tissues.

多個未呈現的事件被呈現是完全依賴時間性空間的部分重疊，連續不斷的會集在時間和空間上，一連串的事件可能同時被發生以便一個現象能在另一個正確的時間和地點活動，相互影響的一個時間性空間形式的發展在細胞和組織之間的整個個體發生過程必須被看作為一個精確的項目表。

Some geneticists believe that induction comes about through the biochemical alteration of regional, cellular environments (Bonner, 1952). These alterations have the effect of activating specific genes that had been present earlier but had been in some state of dormancy. Gene activation induces a new type of protein-synthesis within the cell, a molecular reconstitution, resulting in cell and tissue differentiation (Markert, 1963). Different internal environments activate different genes. Thus cells are acted upon by their environment which, however, is itself made up of cells and their metabolic products; a very complex chain of events ensues, until a relatively steady state, called maturity, is reached.

一些遺傳學家相信誘導來自於生物化學的局部改變和細胞組成的環境(Bonner, 1952)。基因的活化會引起細胞內產生新的形式的蛋白質複合體，而細胞和組織之間的差異會導致分子的重新構成(Markert, 1963)。不同的內部環境會活化出不同的基因，因此細胞作用在新陳代謝的環境，它的組成包括細胞和它的代謝物；一系列非常複雜的事件會接著發生，直到到達穩定的狀態，也就是成熟。

As cells become differentiated, various kinds of enzymes are produced by them that serve as catalysts for thw biochemical reactions involved in development as well as in general metabolic function of the whole organism. The synthesis and biochemical structure of the enzymes are directly controlled by the molecular structure of genes, and small alterations in the latter (due to mutation) may easily affect the catalyzing efficiency of the enzymes and thereby change the temporal proportions of many far reaching reactions. The untoward temporal irregularities may affect growth rates by failing to initiate or inhibit growth activities, and this may result in irregularities of spatial contiguities and relations , thereby altering the entire spatial-temporal pattern. We see now how genes may be responsible for the inheritance of certain structural characteristics such as the famous Hapsburg lip, or a shortening of the chin, or excessively long legs. In these instances, growth is allowed to continue unhampered for a slightly longer time than is common, or it may be inhibited at a slightly earlier period.

當細胞變得有差異時，不同種的酵素也因此產生，它們用來當作整個生物體新陳代謝和生化反應的催化劑。酵素的综合體和生化結構是經由基因的分子結構直接控制，一點後來的改變可能很簡單就會影響它的催化效率，也因此改變了很多深遠的回應的暫時比例。不幸的，暫時的不規則事物可能會因開始的缺失或者抑制發展活動而影響生長速率，並且也可能導致空間接觸和關係的不規則事物改變了整個空間暫時的形式。我們現下看見基因可能怎樣對像著名的Hapsburg嘴唇那樣的某些架構上的特性的繼承負責，或是縮短的下巴、過分長的腿。在這些實例裡，發展被允許繼續下去而未受阻，稍微有點長的時間比是普通的，或者它可能被抑制在一個稍微有點早期的時期。

But, as is well known, genes do not merely control the size and shape of structure but skills and capacities as well (Bernstein, 1925; Haecker and Ziehen, 1922, McClearn, 1964). These too may very well be due to spatio-temporal alterations in the ontogenetic schedules. For instance, the differential growth of internal or peripheral organs may clearly be accompanied by differences in capacities; enlarged heart and lung may improve the ability to run; an enlarged liver the endurance for prolonged intake of alcoholic beverages; a thinning of the fingers, the capacity for assembling electronic equipment. Some skills may beimproved through structural alterations that have the effect of lowering sensory thresholds, whereas the ability to dive may be enhanced by a heightening of tolerance for CO concentration in the blood.

但是，眾所皆知，基因不僅控制生物體的大小和外型，同時也決定了技巧和能力(Bernstein, 1925; Haecker and Ziehen, 1922, McClearn, 1964)。例如，內部或者外圍器官的不同發展，顯然地伴隨著能力的差別； 擴大的心臟和肺可以增進跑步的能力； 一個擴大的肝較有忍耐力對於喝較長期酒類的飲料； 手指的變細，就有裝配的電子設備的能力。一些技能也許被改進，經由降低知覺閾值的作用的結構改變, 但是潛水能力也許增加，經由提高CO濃度在血液中的容忍度。

More directly related to temporal events during ontogeny may be the prolongation of certain primitive undifferentiated stages. By postponing differentiation, either specific tissues or perhaps the entire developing individual, may become more susceptible to environmental influences (either the internal or external environment) and this may result in the creation of various types of critical periods such as have been briefly discussed in Chapter Four. These considerations make it clear that it is not strictly correct to speak of genes for long ears, for auditory acuity, or for the capacity for language. Genes can only affect ontogenesis through varying the cells’ repertoire of differentiation, but this, in turn, may have secondary effects upon structure, function, and capacities.

更多直接相關時間性事件在個體發育時期可能因某些早期不明顯階段而延長。因延後分化，任何一個發展中的個體，可能會變得更易受環境作用(內部或外部環境)的影響，並且這也許導致各種不同類型的重要時期像是在第四章裡簡要的詳述。這些原因使我們清楚的知道，它不僅僅因為了使有恰當的說話而有了長耳朵的基因，也有聽覺敏銳和語言容量的特性。基因可能只經由改變細胞的不同功能來影響個體發育，但依次說，它第二作用在的就是結構、功能和容量。

(2) Relative Growth

Certain aspects of growth can be quantified and treated mathematically. Let us merely refer to one instance, namely the phenomenon of allometric growth. Different portions of the body and limbs grow at different rates, and, therefore, an animal’s proportions are altered throughout development (Fig. 6.5). This is partly due to the existence of growth gradients (J. Huxley, 1932) along various axes of trunk and limbs. It has been found empirically (Reeve and Huxley, 1945) that the relation between the size and weight of two parts of the body (y and x) is that of an exponential function of the form

y = ax,

where a and b are constants. It is convenient to write this formula in its logarithmic form

log y = log a + b log x

and to plot measurements on double logarithmic paper so that all exponential functions appear as straight lines. If, for instance, we plot the weight of cats’ brains against the weight of the same animals’ body weights and take measurements at various stages of development, we find that the simple relationship, expressed by the allometric formula holds fairly well throughout ontogenetic development. The curves indicate differences in growth rate in various parts of the body and show that the proportion between such rates remains constant. The curves do not reflect the actual time it takes the animal to attain any of the values.

(2)相對的發展

發展的某些方面可能被確定數量並且以數學的方式測量。 讓我們僅僅提及一個實例，即異速生長的現象。身體和四肢的不同部份以不同的速度生長,動物比例在整個發展期間中會改變。 這部分由於發展坡度的存在經由多種的軀幹和四肢的軸線。根據經驗， 在身體的兩個部分:尺寸和重量之間的關係是一個指數函數的形式:

y = ax,

a和 b皆是常數。 它便於以它的對數的形式來寫這個公式

log y = log a + b log x

並且在雙倍的對數坐標紙上描繪，讓它能以指數函數作為直線出現。如果，舉例來說，我們描繪貓大腦的重量以及相同重量的動物的大腦重量，然後測量發展的各個時期。我們發現以異速生長公式表示的簡單的關係在整個個人發展期間分配得相當平整。曲線指出在身體的不同的部分的成長率的差別和顯示在這樣的比率之間的比例保持不變。這個曲線並沒有反應出實際的價值在獲得動物實驗的結果之後。

不同種類的生物會有他不同的成長速率，生理上的功能和行為也可能會有不同的成熟率。