Search results
Results From The WOW.Com Content Network
The egg is not retained in the body for most of the period of development of the embryo within the egg, which is the main distinction between oviparity and ovoviviparity. [1] Oviparity occurs in all birds, most reptiles, some fishes, and most arthropods. Among mammals, monotremes (four species of echidna, and the platypus) are uniquely oviparous.
This feature, along with some other genetic similarities with birds, such as shared genes related to egg-laying, is thought to provide some insight into the most recent common ancestor of the synapsid lineage leading to mammals and the sauropsid lineage leading to birds and modern reptiles, which are believed to have split about 315 million ...
A multi-purpose opening terminating at the vent at the posterior of a bird: birds expel waste from it; most birds mate by joining cloaca (a "cloacal kiss "); and females lay eggs from it. Birds do not have a urinary bladder or external urethral opening and (with exception of the ostrich) uric acid is excreted from the cloaca, along with faeces ...
Most arthropods, vertebrates (excluding live-bearing mammals), and mollusks lay eggs, although some, such as scorpions, do not. Reptile eggs, bird eggs, and monotreme eggs are laid out of water and are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are usually kept within a warm and favorable ...
Some birds respond to the accidental loss of eggs by laying a replacement egg. Others will stop laying based on the apparent size of the clutch. According to whether they respond to addition, removal, or both addition and removal of eggs, birds are classified as determinate layers (number of eggs laid is predetermined and do not respond to ...
Of 72 bird species examined around Chicago, roughly a third lay their eggs about 25 days earlier than they did a century ago, researchers report in the paper published on Friday in the Journal of ...
With climate change spurring earlier springs across much of North America, many birds are laying their eggs earlier in the year, according to a new study – adding to mounting evidence that ...
In species in which eggs are laid then buried in sand, indentations in the sand can be a clue to imminent hatching. [9] In sea turtles, this usually occurs about 60 days after the laying of eggs, and often at night. [10] However, exposure to xenobiotic compounds, especially endocrine-disrupting compounds, can affect hatchling sex ratios as well ...