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Gosner stage is a generalized system of describing stages of embryonal and larval development in anurans (frogs and toads). The Gosner system includes 46 numbered stages, from fertilized embryo (stage 1) to the completion of metamorphosis (stage 46). It was introduced by Kenneth Gosner in 1960. [2]
A frog's ear drum works in very much the same way as does a human eardrum. It is a membrane that is stretched across a ring of cartilage like a snare drum that vibrates. Crossing the middle ear chamber there is an ossicle called the columella that is connected to the tympanum, and another ossicle, the operculum, that connects this to the oval ...
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell (spermatozoon). [1] Once fertilized, the ovum becomes a single diploid cell known as a zygote.
Rana (derived from Latin rana, meaning 'frog') is a genus of frogs commonly known as the Holarctic true frogs, pond frogs or brown frogs.Members of this genus are found through much of Eurasia and western North America.
A lymph heart is an organ which pumps lymph in lungfishes, amphibians, reptiles, and flightless birds back into the circulatory system. [1] [2] In some amphibian species, lymph hearts are in pairs, and may number as many as 200 in one animal the size of a worm, while newts and salamanders have as many as 16 to 23 pairs of lymph hearts.
Diets vary widely, with examples including Paracassina, which specializes in snails, [3] and Afrixalus fornasini, the only terrestrial frog known to prey on eggs of other species of anurans. Breeding in this family begins at the start of the rainy season, when hyperoliids congregate at breeding sites.
Pickerel frog egg masses are spherical and about the same size of a wood frog egg mass—roughly 5–10 cm in diameter—although pickerel frog egg masses contain more eggs, about 2000–3000. [4] Pickerel frog eggs are multicolored: they are dark brown on top and cream colored on the bottom.
Frog (Xenopus), as well as other amphibian, gastrulation serves as an excellent example of the role of convergent extension in embryogenesis. During gastrulation in frogs, the driving force of convergent extension is the morphogenic activity of the presumptive dorsal mesodermal cells; this activity is driven by the mesenchymal cells that lie ...