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Gemmules are round balls found on freshwater sponges and are the result of asexual reproduction, essentially spores of the sponge. Gemmules are resistant to dessication (drying out), freezing and anoxia (lack of oxygen) and can lie around for long period of time. When conditions improve gemmules give rise to an adult sponge. December 2005 : January - February - March - April - May - June - July - August - September - October - November - December- → 31 December 2005 (Saturday) 25-year-old Scottish human rights worker Kate Burton and her parents are freed unharmed in the Gaza Strip by the Palestinian gunmen who kidnapped them two days earlier. ... Classes Calcarea Hexactinellida Demospongiae The sponges or poriferans (from Latin porus pore and ferre to bear) are animals of the phylum Porifera. ... Asexual reproduction in liverworts: a caducuous phylloid germinating Asexual reproduction (also known as agamogenesis) is a form of reproduction which does not involve meiosis, gamete formation, or fertilization. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Asphyxia is a condition of severely deficient supply of oxygen to the body. ...
In the late 1800s Charles Darwin and others proposed a mechanism of inheritance of acquired characters by means of gemmules (also called plastitudes or pangenes), which were thought to perhaps reside in the blood.
Darwin proposed that some limited effects from the environment might become embedded in an individual’s constitution and thus be liable to be transmitted, via the gemmules, to the offspring.
Cautiously, he criticised his cousin’s theory, although qualifying his remarks by saying that Darwin’s gemmules (he called them “pangenes”) might be only temporary inhabitants of the blood and that his experiments could have failed to pick them up.
Simply put, the theory holds that body cells shed gemmules which collect in the reproductive organs prior to fertilization.
Atavisms arise due to the awaking of long-dormant gemmules while limbs regenerate due to the activation of gemmules from the missing limb which circulate in the main part of the body.
While the theory was of little use for biologists, it proved exceedingly useful to the nascent science of statistics, and was taken up in a major way by his cousin Francis Galton in his development of the "biometric" approach to heredity.
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