CHAPTER III
THE SURVIVAL OF THE FIT
The plants that most perfectly meet their conditions are
able to persist. They perpetuate themselves. Their offspring are likely to inherit some of the attributes that enabled them successfully to meet the battle of life. The fit (those best adapted to their conditions) tend to survive. Adaptation to conditions depends on the fact of variation; that is, if plants were perfectly rigid or invariable (all exactly alike) they could not meet new conditions. Conditions are necessarily new for every organism. It is impossible to picture a perfectly inflexible and stable succession of plants or animals.
Breeding.—Man is able to modify plants and animals. All our common domestic animals are very unlike their original ancestors. So all our common and long-cultivated plants have varied from their ancestors. Even in some plants that have been in cultivation less than a century the change is marked: compare the common black-cap raspberry with its common wild ancestor, or the cultivated blackberry with the wild form.
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Fig. 5.—Desirable and Undesirable Types of Cotton Plants. Why?
By choosing seeds from a plant that pleases him, the breeder may be able, under given conditions, to produce
