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The arthropod head problem has been tackled in three main ways in this regard, first by using genetic segmental markers to probe the obscure region in front of the mouth, especially in insects; second by looking at Hox gene expression patterns to detect patterns of homology among different arthropods; and third, by studying gene expression in ...
Unsolved problems relating to the structure and function of non-human organs, processes and biomolecules include: Korarchaeota (archaea). The metabolic processes of this phylum of archaea are so far unclear. Glycogen body. The function of this structure in the spinal cord of birds is not known. Arthropod head problem. A long-standing zoological ...
In chelicerates and crustaceans, the cephalothorax is derived from the fusion of the cephalon and the thorax, and is usually covered by a single unsegmented carapace.In relation with the arthropod head problem, phylogeny studies show that members of the Malacostraca class of crustaceans have five segments in the cephalon, when not fused with the thorax to form a cephalothorax.
Nevertheless, despite being known from many specimens, disputes about its morphology, in particular its head appendages, have made it one of the most controversial of the Chengjiang taxa, and it has been discussed extensively in the context of the arthropod head problem. The genus is named after Fuxian Lake (Fuxian Hu), where it was unearthed.
The evolutionary ancestry of arthropods dates back to the Cambrian period. The group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians (or their constituent clades) in a superphylum Ecdysozoa. Overall, however, the basal relationships of animals are not yet well resolved. Likewise ...
Records from a fourth Boar’s Head plant in New Holland, Michigan, do not show similar problems. Boar’s Head stopped making liverwurst and shuttered its Jarratt, Virginia, plant in September ...
In the diamondback moth, antennae serve to gather information about a host plant's taste and odor. After the desired taste and odor has been identified, the female moth will deposit her eggs onto the plant. [17] Giant swallowtail butterflies also rely on antenna sensitivity to volatile compounds to identify host plants. It was found that ...
Arthropod eyes Head of a wasp with three ocelli (center), and compound eyes at the left and right. Most arthropods have sophisticated visual systems that include one or more usually both of compound eyes and pigment-cup ocelli ("little eyes"). In most cases, ocelli are only capable of detecting the direction from which light is coming, using ...