Species that are most numerous will have the best chance of producing favorable variation.
"Rarity is the precursor to extinction"
As new species are formed thru natural selection, others will become rarer & finally extinct.
The greater the diversity of the species, the better able to adapt to novel circumstances.
Geometric increase of species + Limited resources + Variation = Natural selection.
All species are adapted to their own climate; few inhabit both very hot and very cold climates.
Large beard, diminished waddles; Nature splurges in some places economizes in others.
Natural selection economizes: it won't profit the individual to build up its nutrient in useless structure.
The earth's crust is a vast museum, but its collections were taken at intervals of time vastly remote.
Forms in greater numbers will almost always be favored owing to their greater variability.
No one yet has pinpointed how much divergence there would be between two species that would limit them from breeding.
Some closely related species don't breed hybrids at all while some distant species readily interbreed.
The very process of natural selection constantly works to exterminate the parent and intermediate links.
A useful modification of one part will often have entailed on other parts diversified changes of no use.
The more diversified the descendants, the better their chances at succeeding in the battle for life.
Natural selection often produces structures for the injury of other species, such as the fang of the adder
While we don't see many transitional states in the fossil record, we should be cautious asserting that none existed.
Natural selection produces a perfection only according to the standard of the immediate environs.
It's a mistake to assume most instincts are generated by habit handed down to succeeding generations.
There is no fundamental difference between species and varieties.
Some cross breeding leads to vigorous new traits, though too extreme of cross-pollination will lead to sterility
Sans numerous connecting links, “it may be objected that time will not have sufficed for so great an amount of organic change.”
Natural Selection’s greatest weakness: The “extreme imperfection” of the geological record.
“The thickness & extent of sedimentary formations are the result & measure of the degradation which earth’s crust has elsewhere suffered.”
“He who most closely studies ... the sea on our shores will ... be most deeply impressed with the slowness with which rocky coasts are worn away”
“Our richest geological museums” have but a “paltry display”: Darwin on poor paleontological record of evolution
Land rising from the sea will leave a great fossil variety; subsiding, breaking into the sea, it will leave little
Where sediment under the sea did not accumulate quickly enough to protect bodies from decay, no remains can be found.
During periods of subsidence, there will be much extinction of life. During the periods of elevation, much variation.
“We do not make due allowance for the enormous intervals of time which have probably elapsed between our consecutive formations.”
“Continents may have existed where oceans are now spread out; and clear and open oceans may have existed where our continents now stand.”
“To the question why we do not find records of these vast primordial periods, I can give no satisfactory answer”
“Of this volume only here & there a short chapter has been preserved. Of each page, only ... a few lines.”
“Species of different genre and classes have not changed at the same rate, or in the same degree.”
Natural Selection: The belief that each variety/species survives by “having some advantage over those with which it comes into competition.”
Means of dispersal for Species: change of climate must have had a powerful influence on migration.
The same species in distant points of the earth’s surface can be explained by each species having migrated from a single birthplace.
He “who rejects the vera causa of ordinary generation with subsequent migration & calls in the agency of a miracle”
Dried hazelnuts floated for 90 days, and afterwards, when planted, they germinated; an asparagus plant for 23 days
“I picked up in my garden 12 kinds of seeds, out of the excrement of small birds. Some of them ... germinated.”
Blown across vast distances by gales, birds can be highly effective agents in the transportation of seeds.
Some habitual actions do become instinctual through inheritance
“From the first dawn of life, all organic beings are found to resemble each other in descending degrees.”
“A classification founded on any single character, however important that may be, has always failed.”
Wide ranging species not only crossed barriers but were “victorious in distant lands in the struggle for life.”
A mollusk on a duck foot can last 12-20 hours, the time it’d take the duck to fly 600 miles.
“Nothing is thus added to our added to our knowledge” referring to “the Plan of the Creator”
The less any part of the organization is concerned with special habits, the more important it is for classification.
“What can be more curious than that a hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bar, should all be constructed on the same pattern.”
All true classification is genealogical; community of descent is the hidden bond naturalists have been seeking.
“This whole volume is one long argument”
“The innumerable species, genera, and families of organic beings, with which this world is people’d, have all descended, each within its own class or group, from common parents.”
Rudimentary organs, though largely useless, offer a clue as to the derivation of the species
“An organ useful under certain conditions might become injurious under others ... in this case natural selection would continue slowly to reduce the organ, until it was rendered harmless and rudimentary”
“Nothing can be plainer than that wings are formed for flight. Yet in how many insects do we see wings so reduced in size as to be utterly incapable of flight?”
Complex organs and instincts have been perfected by the mere “accumulation of innumerable slight variations, each good for the individual possessor.”
“All the organic beings which have ever lived on this earth, have descended from some one primordial form, into which life was first breathed.”
“I believe that animals have descended from, at most, only four or five progenitors. And plants from an equal or lesser number.”
“But do they really believe that, at innumerable periods in the earth’s history, certain elemental atoms have been commanded suddenly to flash into living tissue?”
“...To think we give an explanation when we only state a fact.”
“It can not be asserted that organic beings, in a state of nature, are subject to no variation. It can not be proved that the amount of variation, in the course of long ages, is a limited quantity.”
“All past and present organic beings constitute one grand natural system, with groups subordinate to group ... the affinities of all organic beings are due to inheritance or community of descent. The natural system is a genealogical arrangement..”
“But as all groups can not thus succeed in increasing in size, for the world will not hold them, the dominant groups beat the less dominant.”
“Dominant species, belonging to the larger groups, tend to give birth to new and dominant forms, so that each large group tends to become still larger and at the same time more divergent in character.”
But success will often depend on having special weapons or means of defense. Or on the charms of the male. And the slightest advantage will lead to victory.”
“The most vigorous individuals, or those which have most successfully struggled with their conditions of life, will generally leave most progeny.”
“But man can and does select the variations given to him by nature, and thus accumulate them in any desired manner. He thus adapts animals and plants to his own benefit and pleasure.”
“Man does not actually produce variability. He only unintentionally exposes organic beings to new conditions of life, and then nature acts on the organization and causes variability.”
“For very, very long periods of time, there will always be a good chance for wide migration by many means.”