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Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip.
Sunflower sea star regenerates its arms. Dwarf yellow-headed gecko with regenerating tail. Regeneration in biology is the process of renewal, restoration, and tissue growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. [1]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
Micrograph showing condensed chromosomes in blue, kinetochores in pink, and microtubules in green during metaphase of mitosis. In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells.
The Neuronal cell cycle represents the life cycle of the biological cell, its creation, reproduction and eventual death. The process by which cells divide into two daughter cells is called mitosis . Once these cells are formed they enter G1, the phase in which many of the proteins needed to replicate DNA are made.
The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by prehistoric temnospondyls such as Mastodonsaurus which could reach up to 6 m (20 ft) in length. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.
Three types of cell division: binary fission (taking place in prokaryotes), mitosis and meiosis (taking place in eukaryotes).. When cells are ready to divide, because cell size is big enough or because they receive the appropriate stimulus, [20] they activate the mechanism to enter into the cell cycle, and they duplicate most organelles during S (synthesis) phase, including their centrosome.
Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, but some species have developed behavioural adaptations to bypass this. Young amphibians generally undergo metamorphosis from an aquatic larval form with gills to an air-breathing adult form with lungs .