Essay help sydney
There are also cases in which varieties have been ally perma- found to continue so long, and to maintain so com- n pletely distinct a character, that it has become diffi- cult, if not impossible, to determine whether they do not constitute a sub-species. And so far as any speculation can be carried on a subject so little under- stood, it would seem most probable that wherever such permanency has been attained, there is essay help sydney always some peculiarity in external conditions which has been the determining cause for the perpetuation of B B 4 376 PHILOSOPHY OF CREATION. Perma- nence of certain species ac- companied by changes in others.
It is there- fore a fair inference that, if the favourable conditions were continued, and the variety were locally isolated from the rest of the species, it would become a per- manent type or species. Within certain limits we observe species fixed at the present day: we have, in some instances, proofs from historical monuments and preserved re- mains that they have not altered within very high limits of antiquity. Again, it is the fact that there are at present Difficulty of marking numerous instances in which naturalists are at is- s P eclfic dis - tinctions. The distinctions admitted as those of species are indeed essay help sydney in some cases much more minute than in other instances, those considered to mark only varieties. The American butterfly the (Vanesso Atalanta) is held to be a distinct species, yet its characteristic is only a single spot on the wing. Nevertheless, the entire black skin of the Negro and the white of the European mark only varieties. In a report formally put forth by the British Association, it is expressly set clown as a DESIDERA- TUM to discover some sure mode of distinguishing real species from local varieties. Carpenter : " The uncertainty of the limits of species is daily becoming more and more evident, and every naturalist is aware that a very large number of races are usually considered as having a distinct origin, when they are nothing more than permanent varieties of a common stock. But if such " permanent varieties " present cha- racters so constant, the real bearing of the question is evident, Why may not other or all " reputed species " have once originated in the same way? And here, indeed, another somewhat material increase in number of question arises : as discoveries and explorations ex- species. It has been stated on good authority that by the Keai num- recent progress of research the number of known species in- finite.
Yet suffi- The close approximation in character between dent prac-. The alarm felt lest the power of making specific ESSAY III. When the distribution of continents and oceans, the eleva- tions of land, the direction of currents, and the like circumstances, shall have undergone a great and notable change, influencing the climate and pro- ductions of existing lands, and even presenting new regions for the diffusion of life, we might then well expect that forms of existing species might be lost, and that such an entire change of species, and eventually even of whole genera, might gradually take place as would fully exemplify, and account for, the observed changes in ancient formations.
Difficulties If i n the case of man they have occurred as transi- of the ques- tion, tional varieties, how comes it that they have become so inveterately essay help sydney permanent? And if those changes have all occurred within the lapse of a few thousand years of the received chronology, it cannot with any reason be denied that similar changes might occur among inferior animals, and become just as per- manent. And if so, changes to an indefinitely greater extent might occur in indefinite lapse of time. If these changes take place by the gradual operation of natural causes, it would be preposterous to deny the possibility of equal or greater changes by equally natural causes in other species in equal eludes that there are either eleven species, or only one, of the human race. The peculiar characters of the Negro race are recorded as prominently marked, as at present, in the ancient Egyptian paintings, which may go back 3000 years or more.
And then we have to ask, How long must it have taken, at this rate of imperceptible progress, to have been deve- loped out of the original stock?
Another essay help sydney instance has been much dwelt upon, the Varieties of the dog. The cases commonly referred to should be regarded by an unprejudiced mind as probably exceptional, under peculiar conditions, and not to be dogmatised upon, as involving any real and necessary law of organised existence.
As there are limits beyond which union will not take place, so within these there may very probably be certain limits of still nearer affinity, beyond which sterility in the offspring prevails, but which have not yet been determined.
The recurrence to the original type often observed, only proves that conditions are ESSAY III. Yet the immutability of species, as something Hypotheses 3 ofimmuta- essential to their nature and inherent in it, has been billt y of species. It is indeed difficult to say what extent of mys- ticism is not connected in the minds of some with the notion of the immutability of species. Opposite But in other schools, especially on the Continent, opposite views are extensively maintained, and pro- bably gaining ground. In the case of plants more particularly, it is simply as a question of facts, that some eminent botanists view the matter. Thus one of the most distinguished foreign naturalists, Prof. How, then, if the same influences which have called forth an aberration from the original form of the plant, continue to act in the same way, not for centuries or tens of cen- turies, but for ten or a hundred thousand years, will not at last, as the variety thus becomes a sub-species, so also, this, become so permanent, that we shall and must describe it as a species.