Search results
Results From The WOW.Com Content Network
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
The black-chinned hummingbird (Archilochus alexandri) is the bird species known to have the smallest genome among birds, which is only 0.91 Gb long.The genomic evolution of birds has come under scrutiny since the advent of rapid DNA sequencing, as birds have the smallest genomes of the amniotes despite acquiring highly derived phenotypic traits.
Sexual selection in birds concerns how birds have evolved a variety of mating behaviors, with the peacock tail being perhaps the most famous example of sexual selection and the Fisherian runaway. Commonly occurring sexual dimorphisms such as size and color differences are energetically costly attributes that signal competitive breeding ...
This orange colouration is generally vibrant in adult males, and often quite muted in females and young cockatiels. Visual sexing is often possible with this variant of bird. [3] A normal grey cockatiel with some white or yellow feathers on the back of their head is split to the recessive mutation Pied. [2]
A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents.
Atavism has also recently been induced in avian dinosaur (bird) fetuses to express dormant ancestral non-avian dinosaur (non-bird) features, including teeth. [11] Other examples of observed atavisms include: Hind limbs in cetaceans and sirenians. [3] [12] Extra toes of the modern horse. [3] [13] [14] Reappearance of limbs in limbless ...
Changes in anatomy are rearrangement of body mass, adults retain juvenile traits including large brain mass and eyes despite a smaller snout (paedomorphism), and aerial abilities. (Michael S. Y. Lee, Andrea Cau, Darren Naish, and Gareth J. Dyke) [1] The Archaeopteryx was the first fossil bird recorded with evolved feathers. [2]
Fisher's fundamental theorem – Principle relating genetic variance to fitness; Neutral theory – Theory of evolution by changes at the molecular level; Shifting balance theory – One version of the theory of evolution; Price equation – Description of how a trait or gene changes in frequency over time