The Life-Cycle includes the enumeration of the sequence of such phases ; 

 and this may become further complicated in Angiosperms by differentiation in the 

 sporophyte generation of ' micro ' and ' mega ' states, much in the manner of sexual 

 differentiation. 



Note: The term sexual is often transferred from its original meaning of 'sex'- 

 distinctitm, to the process of the nuclear fusion (syngamy). 



Theory of Wastage : The Life-History of the Angiosperm represents the gradual 

 perfecting of the mechanism of reproduction over a long sequence of environmental 

 changes, in which all such processes involve an enormous loss to the organism as 

 wastage. The diminution of such wastage is the criterion of higher organism ; but 

 as one method of wastage is corrected in advancing races, so a new one, probably 

 still greater, may be introduced. Three main sources of wastage may be traced in 



I. Sexual Wastage : In the oldest phase of algal life in the sea, as organism of 

 single cells, sexual fusions would involve a wastage of 50 per cent, of the individuals, 

 even admitting the extremely vague chance of rinding another gamete ; while the 

 chance of the zygote ever finding a suitable substratum may be practically nil. 



(a) Apogamy, or Asexuality, saves the wastage of the fusion-function, but is still 



open to that of dispersal. 

 (0) Fertilisation in situ saves the wastage of the female gametes with the food- 



supply of the zygote (all Land Flora, as Archegoniatac). 

 (y) Siphonogamy saves the wastage of the male gametes (higher G) mnosperms, and 



absolute in Angiosperms). 

 The sexual process is ultimately freed from wastage, and this problem is solved. 



II. Asexual Wastage : In Land-plants the asexual spore is subjected to a new 

 form of wastage of air-borne spores, even worse than anything in the sea. The spores 

 differentiate into smaller microspores, and larger megaspores as food-storing units. 

 The latter are ultimately no longer shed, but are pollinated in situ, resulting in the 

 seed-stage as a direct consequence, hence : 



(a) The Seed-habit saves the wastage of the megaspores, but the microspores are 

 still wasted owing to wind-pollination being vaguely efficient. 



(/3) Entomophily solves the problem of the wastage of the microspore ; the more as 

 the pollen-grains are taken all together and placed exactly where wanted, none 

 being lost in transit (cf. Pollinia of Orchids) ; but in no case as yet absolutely 

 without some loss (as in non-visited flowers). 



III. Embryo Wastage : Though the seed-habit saves the megaspore from being 

 wasted on discharge, the embryo has still to be detached at a later date for dispersal 

 purposes, and wastage falls all the more on this stage. Hence the greatest wastage 

 of the Angiosperm is now expressed in terms of lost seeds (notwithstanding the solution 

 of intervening problems), the original difficulty being shifted a step further on, and 

 still unavoidable. Such wastage is expressed in : 



1) Failure to find unoccupied ground. 



2) Chances of death by desiccation on the way. 



3) Competition on germination with other types of organism. 



4) Competition with organisms of the same class (i. e. species). 

 These conditions may be compensated by : 



( i ) Effective dispersal mechanism, and means of transportation ; hence expressing 

 the value of the smallest advantage in terms of wind or animal agency. 



(2) Effective protective investments of testa, fruit-walls (indehiscent fruits); sclero- 

 carp of drupes ; sclerosis of nuts, &c., as many of the most advanced types of 

 xeromorphic fruit-organization. 



(3) Storage of large quantities of food for early stages of the seedling; rapid 

 digestion of reserves, exalbuminous seeds, hypogeal seeds ; including the more 

 specialized, higher, types of seed-organization. 



(4) The most difficult problem, supposing organisms of one race or line of descent 

 are identical ; but the individuals produced by sexual reproduction are not 

 exactly alike one another, or the parents, and do not start on equal terms. 

 Hence the value of even the smallest variations, the latter being apparently 

 introduced in the phenomena of mciosis, and thus indirectly establishing the 

 significance of the sexual fusion which renders meiosis obligatory. 



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