Search results
Results from the WOW.Com Content Network
The muscles connected to the ears of a human do not develop enough to have the same mobility allowed to monkeys. Arrows show the vestigial structure called Darwin's tubercle. In the context of human evolution, vestigiality involves those traits occurring in humans that have lost all or most of their original function through evolution. Although ...
In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function. Vestigiality is the retention, during the process of evolution , of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [ 1 ]
Viviparus viviparus is a species of large freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Viviparidae, the river snails. This species is a viviparous ( ovoviviparous ) snail.
Viviparidae, sometimes known as the river snails or mystery snails, are a family of large aquatic gastropod mollusks, being some of the most widely distributed operculate freshwater snails. This family is classified in the informal group Architaenioglossa according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 .
Gastropods are capable of being either male or female, or hermaphrodites, and this makes their reproduction system stand out amongst many other invertebrates. Hermaphroditic gastropods possess both the egg and sperm gametes which gives them the opportunity to self-fertilize. [4] C. obtusus is a snail species of the Eastern Alps. In the ...
The Chinese mystery snail, black snail, or trapdoor snail (Cipangopaludina chinensis), is a large freshwater snail with gills and an operculum, an aquatic gastropod mollusk in the family Viviparidae. [3] [4] The Japanese variety of this species is black and usually a dark green, moss-like alga covers the shell. [citation needed]
[62] [63] The gills, which are much more efficient than those of other mollusks, are attached to the ventral surface of the mantle cavity. [61] There is a trade-off with gill size regarding lifestyle. To achieve fast speeds, gills need to be small – water will be passed through them quickly when energy is needed, compensating for their small ...
Pharyngeal clefts resembling gill slits are transiently present during the embryonic stages of tetrapod development. The presence of pharyngeal arches and clefts in the neck of the developing human embryo famously led Ernst Haeckel to postulate that " ontogeny recapitulates phylogeny "; this hypothesis, while false, contains elements of truth ...