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After internal fertilization and the habit of laying eggs in terrestrial environments became a reproduction strategy amongst the amniote ancestors, the next major breakthrough appears to have involved a gradual replacement of the gelatinous coating covering the amphibian egg with a fibrous shell membrane. This allowed the egg to increase both ...
Fertilization is the fusion of two gametes. [1] Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. [2] Mating may also lead to external fertilization, as seen in amphibians, fishes and plants. For most species, mating is between two individuals of opposite sexes.
A pair of clicking stream frogs (Strongylopus grayii) in amplexus Orange-thighed frogs (Litoria xanthomera) in amplexusAmplexus (Latin "embrace") is a type of mating behavior exhibited by some externally fertilizing species (chiefly amphibians and horseshoe crabs) in which a male grasps a female with his front legs as part of the mating process, and at the same time or with some time delay, he ...
The spawn (eggs) of a clownfish.The black spots are the developing eyes. Spawn is the eggs and sperm released or deposited into water by aquatic animals.As a verb, to spawn refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is known as spawning.
[citation needed] Internal fertilization with many vertebrates (such as all reptiles, some fish, and most birds) occurs via cloacal copulation, known as cloacal kiss (see also hemipenis), while most mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization. [3] [4]
Fertilization is the fusion of gametes to produce a new organism. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depending on the animal species, the process can occur within the body of the female in internal fertilization, or outside in the case of external fertilization.
Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea, and parasitic wasps), and a few vertebrates, such as some fish, amphibians, and reptiles. This type of reproduction has been induced ...
Biology of the Reptilia is an online copy of the full text of a 22-volume 13,000-page summary of the state of research of reptiles. HerpMapper is a database of reptile and amphibian sightings; Amphibian and Reptile Atlas of Peninsular California, San Diego Natural History Museum; A Primer on Reptiles and Amphibians; Field Herp Forum