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Thrombolites can be distinguished from microbialites or stromatolites by their massive size, which is characterized by macroscopic clotted fabric. Stromatolites are similar but consist of layered accretions. Thrombolites appear with random patterns that can be seen by the naked eye, while stromatolites has the texture of built-up layers. [2]
The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the Late Ordovician mass extinction and Permian–Triassic extinction event decimated marine animals, falling back to earlier levels as marine animals recovered. [30]
Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. [1] The oncoids often form around a central nucleus, such as a shell fragment, [ 2 ] and a calcium carbonate structure is deposited by encrusting microbes .
The experimental observation that all objects in free fall accelerate at the same rate, as noted by Galileo and then embodied in Newton's theory as the equality of gravitational and inertial masses, and later confirmed to high accuracy by modern forms of the Eötvös experiment, is the basis of the equivalence principle, from which basis ...
The Pilbara region of Western Australia contains the Dresser Formation with rocks 3.48 Gya, including layered structures called stromatolites. Their modern counterparts are created by photosynthetic micro-organisms including cyanobacteria. [86] These lie within undeformed hydrothermal-sedimentary strata; their texture indicates a biogenic origin.
Image of the human brain showing sulci, gyri, and fundi shown in a Coronal section. Specific terms are used to represent the gross anatomy of the brain: A gyrus is an outward folding of the brain, for example the precentral gyrus. A sulcus is an inward fold, or valley in the brain's surface - for example the central sulcus. Additional terms ...
The soma of a neuron (i.e., the main part of the neuron in which the dendrites branch off of) contains many organelles, including granules called Nissl granules, which are composed largely of rough endoplasmic reticulum and free polyribosomes. [5] The cell nucleus is a key feature of the soma.
The cerebral cortex, also known as the cerebral mantle, [1] is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals.It is the largest site of neural integration in the central nervous system, [2] and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness.