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The sympathetic trunk is a fundamental part of the sympathetic nervous system, and part of the autonomic nervous system.It allows nerve fibres to travel to spinal nerves that are superior and inferior to the one in which they originated.
Decompression in the context of diving derives from the reduction in ambient pressure experienced by the diver during the ascent at the end of a dive or hyperbaric exposure and refers to both the reduction in pressure and the process of allowing dissolved inert gases to be eliminated from the tissues during this reduction in pressure.
This is the most common form of vertical migration. Organisms migrate on a daily basis through different depths in the water column. Migration usually occurs between shallow surface waters of the epipelagic zone and deeper mesopelagic zone of the ocean or hypolimnion zone of lakes. [2]
To ascend, the diver fins upward, generally assisted by buoyancy as the surface is approached. In competitive freediving the techniques for descent and ascent are largely specified by the rules of the specific discipline, and are quite varied, and range from unaided swimming, to pulling oneself along a shotline, to descending using a heavy ...
The tree of life or universal tree of life is a metaphor, conceptual model, and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859).
The spinothalamic tract is a nerve tract in the anterolateral system in the spinal cord. [1] This tract is an ascending sensory pathway to the thalamus.From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory cortex of the postcentral gyrus.
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth.
An alternative definition does not require any members of a crown group to be extant, only to have resulted from a "major cladogenesis event". [6] The first definition forms the basis of this article. Often, the crown group is given the designation "crown-", to separate it from the group as commonly defined.