Evolution and animal life, an elementary discussion of facts, processes, laws and theories relating to the life and evolution of animalsD. Appleton, 1908 - 489 páginas |
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Página 53
... breed together , in order that the particular variations ( which from the point of view of the student of species - forming may be called also the particular varietal differences that are to become in time so developed and fixed as to ...
... breed together , in order that the particular variations ( which from the point of view of the student of species - forming may be called also the particular varietal differences that are to become in time so developed and fixed as to ...
Página 54
... breeding among themselves . But such an isolation may conceivably be brought about in several other ways , and observation has shown that probably in some cases so - called biologic isolation occurs , that is , that a restriction of ...
... breeding among themselves . But such an isolation may conceivably be brought about in several other ways , and observation has shown that probably in some cases so - called biologic isolation occurs , that is , that a restriction of ...
Página 58
... breeding with the mass . In a world of varying conditions with varying organisms , it is not conceivable that species should , through all their generations , undergo no change . Nor in the changes of any species is it possible that any ...
... breeding with the mass . In a world of varying conditions with varying organisms , it is not conceivable that species should , through all their generations , undergo no change . Nor in the changes of any species is it possible that any ...
Página 60
... breeding when thirty years old and goes on breeding until ninety years old , bringing forth six young in the interval and surviving to be a hundred years old . If this be so , after about 800 years there should be 19,000,000 elephants ...
... breeding when thirty years old and goes on breeding until ninety years old , bringing forth six young in the interval and surviving to be a hundred years old . If this be so , after about 800 years there should be 19,000,000 elephants ...
Página 66
... breeding at the age of six months , it is shown that , at this rate , the original pair might be responsible in five ... breed , and give himself and friends an occasional day with the hounds . His modest desires were soon met in the ...
... breeding at the age of six months , it is shown that , at this rate , the original pair might be responsible in five ... breed , and give himself and friends an occasional day with the hounds . His modest desires were soon met in the ...
Outras edições - Ver tudo
Evolution and Animal Life: An Elementary Discussion of Facts, Processes ... David Starr Jordan,Vernon Lyman Kellogg Visualização integral - 1907 |
Evolution and Animal Life: An Elementary Discussion of Facts, Processes ... David Starr Jordan,Vernon Lyman Kellogg Visualização integral - 1907 |
Evolution and animal life, an elementary discussion of facts, processes ... David Starr Jordan,Vernon Lyman Kellogg Visualização integral - 1907 |
Palavras e frases frequentes
actual adaptation adult animals animals and plants ants apes appear artificial selection bees beetles biologists birds body breeding butterfly called causes centrosome changes CHAPTER characters chromatin chromosomes color and pattern common crab Darwin degeneration degree descent differentiation division egg cell embryo environment existence fact factors fauna female fertilized fishes forms fossils genus germ cells habit hatched heredity honeybee host hybrid individuals influence inheritance insects instinct islands isolation kinds of animals known larva larvæ live lower male mammals matter ment modified mutations natural selection naturalists nest nucleus offspring organic evolution origin Origin of Species parasites parent phenomena plasm primitive produced protoplasm Protozoa race relation reproduction reptiles resemblance Sacculina sea anemone sexual sexual selection sheep species species-forming sperm spines stage structure substance tail theory tion traits tree variation various vertebrates Weismann wings workers young