Beard’s theory of the alternation of generations and the abderhalden pregnancy reactions—A criticism

1919 ◽  
Vol 37 (1) ◽  
pp. 408-412
Author(s):  
W. M. Crofton
Keyword(s):  
Alternation Of Generations

scholarly journals On Apogamy and the development of Sporangia upon fern prothalli

1898 ◽  
Vol 63 (389-400) ◽  
pp. 56-61
Keyword(s):  
Life History ◽  
Point Of View ◽  
The Other ◽  
Normal Life ◽  
Other Hand ◽  
General Importance ◽  
Two Generations ◽  
History Of ◽  
Alternation Of Generations

The two most important deviations from the normal life-history of ferns, apogamy and apospory, are of interest in themselves, but acquire a more general importance from the possibility that their study may throw light on the nature of alternation of generations in archegoniate plants. They have been considered from this point of view Pringsheim, and by those who, following him, regard the two generations as homologous with one another in the sense that the sporophyte arose by the gradual modification of individuals originally resemblin the sexual plant. Celakovsky and Bower, on the other hand, maintaint the view tha t the sporophyte, as an interpolated stage in the life-history arising by elaboration of the zygote, a few thallophytes.

Alternation of Generations

2008 ◽  
pp. 136-136
Author(s):  
George Hangay ◽  
Severiano F. Gayubo ◽  
Marjorie A. Hoy ◽  
Marta Goula ◽  
Allen Sanborn ◽  
...  
Keyword(s):  
Alternation Of Generations

Alternation of Generations in Plants and Algae

2017 ◽  
pp. 1-14
Author(s):  
Simon Bourdareau ◽  
Laure Mignerot ◽  
Svenja Heesch ◽  
Akira F. Peters ◽  
Susana M. Coelho ◽  
...  
Keyword(s):  
Alternation Of Generations

Development of Products

2008 ◽  
pp. 167-189
Author(s):  
Toru Higuchi ◽  
Marvin Troutt
Keyword(s):  
The Other ◽  
Other Hand ◽  
Price Decline ◽  
Standard Design ◽  
Dominant Design ◽  
New Generation ◽  
Alternation Of Generations

This chapter explains the advancement and the price decline of products based on the VCR case. After the dominant design emerges, the product advances incrementally or cumulatively because the dominant design sets a standard design of the product and a framework for the competition. Many new generation products appeared in the market with innovative functions to spur sales. Some of them became popular and others did not. In the VCR case, most consumers bought a monaural VHS machine and, then later, a HiFi VHS machine. On the other hand, most consumers did not purchase S-VHS, D-VHS, and other advanced machines because those were too expensive in comparison with their performance. As a result, the alternation of generations of the VCR occurred only once, from the monaural to the HiFi machine.

Alternation of Generations and its Bearings upon Cancer

1919 ◽  
Vol 147 (5) ◽  
pp. 217-225 ◽  
Author(s):  
J. Beaed
Keyword(s):  
Alternation Of Generations

Sex and the Single Cryptogam

2018 ◽  
Author(s):  
Lincoln Taiz ◽  
Lee Taiz
Keyword(s):  
Life Cycle ◽  
Pollen Tube ◽  
Female Parent ◽  
Seed Plants ◽  
Cell Theory ◽  
Entire Life ◽  
Entire Life Cycle ◽  
Cell Divisions ◽  
Material Substance ◽  
Alternation Of Generations

As Chapter 17 makes clear, the asexualist/sexualists controversy continued even as Johann Hedwig and Karl von Nägel demonstrated the existence of sex in cryptogams by discovering the Alternation of Generations (1782, 1784), hybridizers A. F. Wiegman and Carl Friedrich von Gaertner recieved prestigious prizes for their work, and Giovanni Battista Amici and Adolphe-Theodore Brongniart discovered—and confirmed—the pollen tube. Unconvinced, Matthias Jacob Schleiden, co-founder of the cell theory, insisted that ferns grow asexually from spores, and that spores, not seeds, are the primary units of propagation in seed plants also. He argued (1853) that the entire life-cycle of seed plants is based on duplicative cell divisions that produce seeds entirely by vegetative processes. Following the Aristotelian doctrine that the female parent provides the material substance of the embryo, he concluded pollen must be a female structure that reproduces vegetatively—thus making the case for a unisexual, plants-as-female model.

Alternation of Generations in Padina

1919 ◽  
Vol 67 (3) ◽  
pp. 278-278
Author(s):  
C. J. Chamberlain
Keyword(s):  
Alternation Of Generations

Alternation of Generations in Man

1970 ◽  
Vol 13 (2) ◽  
pp. 264-266
Author(s):  
Wayne H. Davis
Keyword(s):  
Alternation Of Generations
Sign in / Sign up

Export Citation Format

Share Document