منابع مشابه
Asexual Reproduction in Holothurians
Aspects of asexual reproduction in holothurians are discussed. Holothurians are significant as fishery and aquaculture items and have high commercial value. The last review on holothurian asexual reproduction was published 18 years ago and included only 8 species. An analysis of the available literature shows that asexual reproduction has now been confirmed in 16 holothurian species. Five addit...
متن کاملVisceral regeneration in holothurians.
Holothurians, or sea cucumbers, exhibit two processes that have intrigued biologists for decades: autotomy and regeneration. Autotomy includes the loss of body parts by evisceration or fission, and regeneration is the extraordinary process by which the lost organs are replaced. In this article, we review the literature on evisceration, transection, and visceral regeneration in holothurians and ...
متن کاملCambrian Lattices
For an arbitrary finite Coxeter group W , we define the family of Cambrian lattices for W as quotients of the weak order on W with respect to certain lattice congruences. We associate to each Cambrian lattice a complete fan, which we conjecture is the normal fan of a polytope combinatorially isomorphic to the generalized associahedron for W . In types A and B, we obtain, by means of a fiber-pol...
متن کاملThe Cambrian explosion
The sudden appearance of fossils that marks the so-called 'Cambrian explosion' has intrigued and exercised biologists since Darwin's time. In On the Origin of Species, Darwin made it clear that he believed that ancestral forms 'lived long before' their first fossil representatives. While he considered such an invisible record necessary to explain the level of complexity already seen in the foss...
متن کاملCambrian Hopf Algebras
Cambrian trees are oriented and labeled trees which fulfill local conditions around each node generalizing the conditions for classical binary search trees. Based on the bijective correspondence between signed permutations and leveled Cambrian trees, we define the Cambrian Hopf algebra generalizing J.-L. Loday and M. Ronco’s algebra on binary trees. We describe combinatorially the products and ...
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ژورنال
عنوان ژورنال: The American Naturalist
سال: 1913
ISSN: 0003-0147,1537-5323
DOI: 10.1086/279367