Search results
Results from the WOW.Com Content Network
Amphisbaenia / æ m f ɪ s ˈ b iː n i ə / (called amphisbaenians or worm lizards) is a group of typically legless lizards, [2] comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes.
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 ...
The term ichthyopsida means fish-face or fish-like as opposed to the Sauropsida or lizard-face animals (reptiles and birds) and the mammals. [6] The group representing an evolutionary grade rather than a clade , the term anamniote is now used as an informal way of denoting the physical property of the group, rather than as a systematic unit.
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.
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Only about 100 of the 12,000 extant reptile species and subspecies are classed as marine reptiles, including marine iguanas , sea snakes , sea turtles and saltwater crocodiles .
Reptiles, from Nouveau Larousse Illustré, 1897–1904, notice the inclusion of amphibians (below the crocodiles). In the 13th century, the category of reptile was recognized in Europe as consisting of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, lizards, assorted amphibians, and worms", as recorded by Beauvais in his Mirror of Nature. [7]
Females store the sperm until ovulation and internal fertilization take place, usually just prior to deposition in the spring. [7] Before the eggs are deposited, male mudpuppies leave the nest. [ 6 ] Once ready, the female deposits the eggs in a safe location, usually on the underside of a rock or log. [ 7 ]
A cross between a toad, Amietophrynus regularis, and a frog, Rana fusca, would not produce a viable embryo, but fertilization of a toad egg by an irradiated frog sperm would produce a haploid larva. [1] Parthenogenesis has also been induced in Pelophylax nigromaculatus by pricking an egg with a needle. [2]