Palaeontological Sentence Examples
In attempting to account for the distribution of existing vegetation we must take into account palaeontological evidence.
Palaeontological evidence conclusively proves that the surface of the earth has been successively occupied by vegetative forms of increasing complexity, rising from the simplest algae to the most highly organized flowering plant.
Here we must mention the intimate connexion between classification and geographical distribution as revealed by the palaeontological researches of Alphonse Milne-Edwards, whose magnificent Oiseaux Fossiles de la France a.
From these structural and palaeontological evidences, geologists suppose that the formation of the cave was carried on simultaneously with the excavation of the valley; that the small streams, flowing down the upper ramifications of the valley, entered the western opening of the cave, and traversing the fissures in the limestone, escaped by the lower openings in the chief valley; and that the rounded pebbles found in the shingle bed were carried in by these streams. It would be only at times of drought that the cave was frequented by animals, a theory which explains the small quantity of animal remains in the shingle.
Elsewhere the identification of the Silurian and older systems does not rest on palaeontological evidence.
Cuvier's morphological doctikne received its fullest development in the principle of the " correlation of parts," which he applied to palaeontological investigation, namely, that every animal is a definite whole, and that no part can be varied without entailing correlated and law-abiding variations in other parts, so that from a fragment it should be possible, had we a full knowledge of the laws of animal structure or morphology, to reconstruct the whole.
Of the forms above indicated there is no palaeontological evidence with regard to the Entoprocta.
The subject of palaeontological botany has been advanced by the researches of both botanists and geologists.
The Cincinnati Society of Natural History (incorporated 1870) has a large library and a museum containing a valuable palaeontological collection, and bones and implements from the prehistoric cemetery of the mound-builders, at Madisonville, Ohio.
Such restorations are possible because of the intimate fitness of animals and plants to their environment, and because such fitness has distinguished certain forms of life from the Cambrian to the present time; the species have altogether changed, but the laws governing the life of certain kinds of organisms have remained exactly the same for the whole period of time assigned to the duration of life; in fact, we read the conditions of the past in a mirror of adaptation, often sadly tarnished and incomplete owing to breaks in the palaeontological record, but constantly becoming more polished by discoveries which increase the understanding of life and its all-pervading relations to the non-life.
AdvertisementWe may first trace in outline the history of the birth of palaeontological ideas, from the time of their first adumbration.
His speculations on phylogeny, or the descent of invertebrates and vertebrates, were, however, most fantastic and bore no relation to palaeontological evidence.
The concurrence of botanical (Hooker, 1847), zoological, and finally of palaeontological evidence for the reconstruction of the continent of Antarctica, is one of the greatest triumphs of biological investigation.
It is equally true that palaeontological evidence has frequently failed where we most sorely needed it.
The sum of the primitive characters approximately restores the primitive form; and the gaps in palaeontological evidence are supplied by analysis of the available zoological, embryological and anatomical evidence.
AdvertisementMarsh, entitled " History and Methods of Palaeontological Discovery " (American Association for the Advancement of Science, 1879).
There is in some places an unconformity between the Richmond beds (or their equivalent) and underlying formations, and this unconformity, together with certain palaeontological considerations, has raised the question whether the uppermost part of the system, as outlined above, should not be classed as Silurian (Upper Silurian).
This reason is reinforced by palaeontological considerations.
In the ice-free belt, between the northern ice-sheet and the vastly extendedglaciers of the Alps, the two floras must have found a common refuge and congenial conditions of existence; and this view is confirmed by direct palaeontological evidence.
But there is no sound basis for the assumption that the Dicotyledons are derived from Monocotyledons; indeed, the palaeontological evidence seems to point to the Dicotyledons being the older.
AdvertisementIn a survey of the palaeontological history of plants and animals, it is plain that extreme stability and extreme mutability both have occurred, sometimes having persisted for untold ages, sometimes having succeeded one another for varying periods.
To-day the recognition of the earliest fossil-bearing rocks, below the Llandeilo formation of Murchison, as belonging to the Cambrian system, and the threefold subdivision of the system according to palaeontological evidence, may be regarded as firmly established.
The university of Pavia has long been famous as a medical school, and has the oldest anatomical cabinet in Italy; in addition it has a natural history museum founded under Spallanzini in 1772, a botanical garden, begun in 1774, and excellent geological, palaeontological and mineralogical collections.
This is shown by palaeontological evidence; and some of the most successful bores, such as those at Coonamble, Moree, Gil Gil and Euroka, have pierced rocks of Triassic age, corresponding with the Ipswich Coal Measures.
This combination of circumstances has given the Graptoloidea a paramount stratigraphical importance as palaeontological indices of the detailed sequence and correlation of the Lower Palaeozoic rocks in general.
AdvertisementThat is to say, he believes that, with the exception of the duckbill and the echidna, the mammalian class as a whole can lay claim to descent from small arboreal forms. This view is, of course, almost entirely based upon palaeontological considerations; and these, in the author's opinion, admit of the conclusion that all modern placental and marsupial mammals are descended from a common ancestral stock, of which the members were small in bodily size.
In all the groups which are at present arboreal, the palaeontological evidence goes to show that their ancestors were likewise so; while since, in the case of modern terrestrial forms, the structure of the wrist and ankle joints tends to approximate to the arboreal type, as we recede in time, the available evidence, so far as it goes, is in favour of Dr Matthew's contention.
Earle, in the American Naturalist for 1897, observes that " so far as the palaeontological evidence goes it is decidedly in favour of the view that apes and lemurs are closely related.
The fact that no Cambrian strata have been established by palaeontological evidence in the west of Ireland has made it equally difficult to establish any pre-Cambrian system.
The remains of the plants of former periods, which have come down to us in the fossilized state, are almost always fragmentary, and often imperfectly preserved; but their investigation is of the utmost importance to the botanist, as affording the only direct evidence of the past history of vegetable organisms. Since the publication of the Origin of Species the general acceptance of the doctrine of evolution has given a vastly increased significance to palaeontological data.
On the other hand, a study of the plant-life of past ages tends to the conviction that too much stress may be laid on the imperfection of the geological record as a factor in the interpretation of palaeontological data.
Consideration of phylogenetic series, especially from the palaeontological side, has led many writers to the conception that there is something of the nature of a growth-force inherent in organisms and tending inevitably towards divergent evolution.
For geographical distribution and anatomical characters see Falconer's Palaeontological Memoirs, vol.
The subject of palaeontological botany (see Palaeobotany) has been advanced by the researches of both botanists and geologists.