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For this reason, fossil collectors commonly break open concretions in their search for fossil animal and plant specimens. [9] Some of the most unusual concretion nuclei are World War II military shells, bombs, and shrapnel, which are found inside siderite concretions found in an English coastal salt marsh. [10]
Pinocytosis. In cellular biology, pinocytosis, otherwise known as fluid endocytosis and bulk-phase pinocytosis, is a mode of endocytosis in which small molecules dissolved in extracellular fluid are brought into the cell through an invagination of the cell membrane, resulting in their containment within a small vesicle inside the cell.
Debates on whether specific forms are pseudo or true fossils can be lengthy and difficult. For example, Eozoön is a complex laminated form of interlayered calcite and serpentine originally found in Precambrian metamorphosed limestones (marbles). It was at first thought to be the remains of a giant fossil protozoan (Dawson, 1865), then by far ...
Pinocytosis, which usually occurs from highly ruffled regions of the plasma membrane, is the invagination of the cell membrane to form a pocket, which then pinches off into the cell to form a vesicle (0.5–5 μm in diameter) filled with a large volume of extracellular fluid and molecules within it (equivalent to ~100 CCVs). The filling of the ...
Reynolds number (Re) is the measure of the relationships between inertial and viscous forces in flow ((animal's length x animal's velocity)/kinematic viscosity of the fluid). Turbulent flow can be found at higher Re values, where the boundary layer separates and creates a wake, and laminar flow can be found at lower Re values, when the boundary ...
When animal or plant matter is buried during sedimentation, the constituent organic molecules (lipids, proteins, carbohydrates and lignin-humic compounds) break down due to the increase in temperature and pressure.
Fossil skeletal parts from extinct belemnite cephalopods of the Jurassic – these contain mineralized calcite and aragonite.. Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, [a] often resulting in hardened or stiffened mineralized tissues.
For most organisms, the resting period is a stage of preparation during which the secretion of fluid from the moulting glands of the epidermal layer and the loosening of the underpart of the cuticle occurs. Once the old cuticle has separated from the epidermis, a digesting fluid is secreted into the space between them.