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OriginOfSpecies - 475 Rows
Column Type #Values Column Stats
id int(11) 475 Column Stats
subject varchar(80) 14 Column Stats
title varchar(250) 139 Column Stats
ordinal int(11) 30 Column Stats
description text 474 Column Stats

475 rows, page 102 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by ordinal limit 404, 4 (Page 102: Row)
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title
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description
04 - Natural Selection 04-08 - On the Intercrossing of Individuals 80 It must have struck most naturalists as a strange anomaly that, both with animals and plants, some species of the same family and even of the same genus, though agreeing closely with each other in their whole organisation, are hermaphrodites, and some unisexual.

But if, in fact, all hermaphrodites do occasionally intercross, the difference between them and unisexual species is, as far as function is concerned, very small.

From these several considerations and from the many special facts which I have collected, but which I am unable here to give, it appears that with animals and plants an occasional intercross between distinct individuals is a very general, if not universal, law of nature.
04 - Natural Selection 04-09 - Circumstances favourable for the production of new forms through Natural Selection 80 But we may thus deceive ourselves, for to ascertain whether small isolated area, or a large open area like a continent has been most favourable for the production of new organic forms, we ought to make the comparison within equal times; and this we are incapable of doing.

Although isolation is of great importance in the production of new species, on the whole I am inclined to believe that largeness of area is still more important, especially for the production of species which shall prove capable of enduring for a long period, and of spreading widely.

Australia
Australia

koala
koala

kangaroo
kangaroo

rabbit
rabbit

mouse
mouse
04 - Natural Selection 04-11 - Divergence of Character 80 The advantage of diversification of structure in the inhabitants of the same region is, in fact, the same as that of the physiological division of labour in the organs of the same individual body- a subject so well elucidated by Milne Edwards.

No physiologist doubts that a stomach adapted to digest vegetable matter alone, or flesh alone, draws most nutriment from these substances.

So in the general economy of any land, the more widely and perfectly the animals and plants are diversified for different habits of life, so will a greater number of individuals be capable of there supporting themselves.

A set of animals, with their organisation but little diversified, could hardly compete with a set more perfectly diversified in structure.

It may be doubted, for instance, whether the Australian marsupials, which are divided into groups differing but little from each other, and feebly representing, as Mr. Waterhouse and others have remarked, our carnivorous, ruminant, and rodent mammals, could successfully compete with these well-developed orders.

Australian
Australian

koala
koala

kangaroo
kangaroo


In the Australian mammals, we see the process of diversification in an early and incomplete stage of development.
04 - Natural Selection 04-12 - On the Degree to which Organisation tends to advance 80 But mammals and fish hardly come into competition with each other; the advancement of the whole class of mammals, or of certain members in this class, to the highest grade would not lead to their taking the place of fishes.

Physiologists believe that the brain must be bathed by warm blood to be highly active, and this requires aerial respiration; so that warm-blooded mammals when inhabiting the water lie under a disadvantage in having to come continually to the surface to breathe. With fishes, members of the shark family would not tend to supplant the lancelet; for the lancelet, as I hear from Fritz Muller, has as sole companion and competitor on the barren sandy shore of South Brazil, an anomalous annelid.

annelid
annelid