. Biology; the story of living things. THE BI()LO(;iC,\L CONQUEST ()\- nil] \\(,|u,|) M\ The question of how long seeds will survive, uiidci- whal condilions they will germinate, and how fast they will grow is of g,vat inipor- tance in the repopulation of areas after soil erosion oi- fire. Beale reports an experiment where ten out of twenty-two species of seeds sprouted after hav- ing been buried in open bot- tles in moist sand at a depth of three feet for over forty years. After a coniferous for- est has been devastated by fire, an entirely new series of plants spring up in the area ; first h
. Biology; the story of living things. THE BI()LO(;iC,\L CONQUEST ()\- nil] \\(,|u,|) M\ The question of how long seeds will survive, uiidci- whal condilions they will germinate, and how fast they will grow is of g,vat inipor- tance in the repopulation of areas after soil erosion oi- fire. Beale reports an experiment where ten out of twenty-two species of seeds sprouted after hav- ing been buried in open bot- tles in moist sand at a depth of three feet for over forty years. After a coniferous for- est has been devastated by fire, an entirely new series of plants spring up in the area ; first herbs, such as fireweed or wild mustard; then trees or bushes, the seeds of which may be brought by birds, as raspberry, blackberry, or wild cherry; later a stage of trees having wind-blown or bird- carried seeds, such as aspen, cottonwoods, or birches. Still later the forest may become repeopled by its original in- habitants, which becomes the climax. Conditions of wind, mois- ture, sunlight, and weather, the sum total of which constitutes climate, play a most important part in succession. If drought destroys life in a given region, an entirely new group of plants may come to occujiy that area, bringing with them a new group of animals. Migrations of animals may be brought about by changing seasons. The biotic conditions governing successions are many. Man, through clearing forests, throwing wastes into ri\ers, or introducing new plants or animals which may compete with existing species, often completely upsets the balance of life and causes succe.'^sioiis. Indus- trial pollution may completely depopulate streams of fish life, bac- terial growth replacing the original plants and animals. Sometimes new organisms add so many competing mouths to feed in a gix'cn terri- tory that it becomes necessary for some to break away if any are to li\('.. Wriijlu I'itrct A lypiciil undt'CKruwtti succession after a I'orcsl ( Please note that these images are extracted from scanned page im
Size: 1290px × 1937px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwalterherberteugeneb1867, bookcentury1900, bookpublish
