. The origin and evolution of life, on the theory of action, reaction and interaction of energy. ell-nucleus ofthe Cyanophyceae or-dinarily is not sharplylimited by a membrane,and there is no evidenceof distinct chlorophyllbodies, although chloro-phyll is present. In thesimpler of the unicel-lular Cyanophyceae theonly method of repro-duction is that knownas vegetative multipli- FiG. 15. Fossil and LivingAlg-E Compared C. A living algal pool colony near the Great Fountain Geyser, Yellowstone Park. After Walcott. B. Fossil calcareous algas, Crypto- zoon prolifcrum Hall, from the Cryptozoon Ledge
. The origin and evolution of life, on the theory of action, reaction and interaction of energy. ell-nucleus ofthe Cyanophyceae or-dinarily is not sharplylimited by a membrane,and there is no evidenceof distinct chlorophyllbodies, although chloro-phyll is present. In thesimpler of the unicel-lular Cyanophyceae theonly method of repro-duction is that knownas vegetative multipli- FiG. 15. Fossil and LivingAlg-E Compared C. A living algal pool colony near the Great Fountain Geyser, Yellowstone Park. After Walcott. B. Fossil calcareous algas, Crypto- zoon prolifcrum Hall, from the Cryptozoon Ledge in Lester Park near Saratoga Springs, N. Y. These algse, which are among the oldest plants of the earth, grew in cabbage-shaped heads on the bottom of the ancient Cambrian sea and deposited lime in their tissue. The ledge has been planed down by the action of a great glacier which cut the plants across, showing their concentric interior structure. Photographed by H. P. Gushing. Fossil alga;, NnvJandia conccntrica, Newlandia Jrondosa, from the Algonkian Belt Series of Montana. After EVOLUTION OF ALG^ 103 cation, in which an ordinary working cell (individual) dividesto form two new individuals. In certain of the higher forms,in which there is some differentiation of connected cells and inwhich we seem justified in considering the individual to bemulticellular, multiplication is accomplished through the agencyof cells of special character known as the spores. No evidencesof sexual reproduction have been observed in the sinter deposits of hot springs and geysers in YellowstonePark are attributed to the presence of Cyanophyceae.^ With the appearance of the true algae the earth-formingpowers of life become still more manifest, and few geologicdiscoveries of recent times are more important than thosegrowing out of the recognition of algae as earth-forming early as 1831 Lyell remarked their rock-forming is now known that there are formati
Size: 1104px × 2264px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyorkcscribnerss
