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6.--SKM photos (A) Racekiela ryderi, gemmulosclere, (B) Racekiela ryderi, gemmulosclere, (C) Rncekiela ryderi, megasclere, (D) Racekiela ryderi, gemmule, (E) Radiospongilla cereMlata, gemmulosclere, (F) Radiospongilla cerebellata, megasclere, (G) Radiospongilla cerebellata, gemmule
White and green sponges were observed in both rivers and contained numerous basal gemmules near attachment with substrate.
Using histological techniques, De Vos (1977) has shown that glycogen is present in the early stages of gemmule formation and later disappears.
In order to survive unfavorable conditions, sponges asexually produce bodies known as gemmules and can also use this life stage for downstream dispersal (Loomis et al., 1996; Manconi and Pronzato, 2008).
Gemmules were lightly visible throughout the sample and were brown to black in color (Figure 1, left).
It is likely that pangenesis lasted longer than it might have otherwise because the proposed gemmules were thought to be too small to be seen with the microscopes of Darwin's time.
However, gemmoscleres (spicules from gemmules) were rare.
(10) Darwin's idea, postulated in The Variation of Plants and Animals under Domestication (1868), was that heredity was passed on through a process he called pangenesis, a complicated system where, in the words of George John Romanes, "every cell in the body casts off 'gemmules,' which are the carriers of heredity from their respective tissues to the germinal elements" (1893a, 512).
5 and 6), suggested that Cliona colonization via waterborne dispersal of larvae and/or asexual fragments (i.e., gemmules) occurred during summer 2012.
Pangenesis posits that each and every part of an organism produces "gemmules" during every stage of the organism's development from embryo to adult.
Carbohydrate mobilization in post-diapausing gemmules of the freshwater sponge, Eunapius fragilis.
Darwin developed his own theory of genetics that was based on blending inheritance-units called "gemmules," but that effort proved fruitless (Mayr, 1982).
Darwin had some famous misunderstandings due to the gaps in scientific knowledge in his time, for example his mechanism of inheritance via gemmules (Darwin, 1871), but Table 1 lists only content in the first edition of On the Origin of Species (Costa, 2009).
Darwin's half cousin Francis Galton (often called the father of eugenics) conducted a series of experiments to test the notion that gemmules moved throughout the body to transmit information to the gametes.
In freshwater invertebrates, dormant stages include gemmules (sponges), statoblasts (bryozoans), and resting eggs (turbellarians, rotifers, and microcrustaceans) (see Pennak 1989).
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