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Male Dendropsophus microcephalus calling. Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts.Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations ...
It is an important structure that plays a critical role in the formation of male reproductive organs. The duct is named after Caspar Friedrich Wolff, a German physiologist and embryologist who first described it in 1759. [1] During embryonic development, the mesonephric ducts form as a part of the urogenital system. [2]
Mesonephric tubules are genital ridges that are next to the mesonephros.. In males, some of the mesonephric kidney tubules, instead of being used to filter blood like the rest, "grow" over to the developing testes, penetrate them, and become connected to the seminiferous tubules of the testes.
g. Its termination in x, the urogenital sinus. h. The duct of Müller. i. Its upper, funnel-shaped extremity. k. Its lower end, terminating in the urogenital sinus. l. The genital gland. This vesicle then elongates to form the mesonephric tubule, attaching to the mesonephric duct on one side. Meanwhile, an artery from the dorsal aorta begins ...
Most male reptiles have copulatory organs, which are usually retracted or inverted and stored inside the body. In turtles and crocodilians, the male has a single median penis-like organ, while male snakes and lizards each possess a pair of penis-like organs. A male common frog in nuptial colors waiting for more females to come in a mass of spawn
The male frog has certain hormone-dependent secondary sexual characteristics. These include the development of special pads on his thumbs in the breeding season, to give him a firm hold. [81] The grip of the male frog during amplexus stimulates the female to release eggs, usually wrapped in jelly, as spawn.
In both amphibians and zebrafish, the pronephros has a single nephron attached to a nephric duct, which in turn is linked to the cloaca. Although these kidneys have a simple anatomical organization with only a single nephron, the nephrons have a segmental and functional complexity that is very similar to that in more complex kidneys such as mesonephroi and metanephroi.
Kidney development, or nephrogenesis, describes the embryologic origins of the kidney, a major organ in the urinary system. This article covers a 3 part developmental process that is observed in most reptiles, birds and mammals, including humans.